[BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Linus Nilsson]

Hi

I have found what I suspect to be a bug, or at least not desirable behavior in my case. In one branch, I have moved all files in a directory to another directory. The first directory is now empty in this branch (I haven't tested whether this is significant). I cherry-picked the commit to another branch that has additional files in the first directory. All the files in the first directory are now moved to the second directory, and not just the files that were moved in the original commit. It happens in Git for Windows, versions 2.20.1 and 2.21.0.

It can be reproduced using these steps:

$ git init
$ mkdir a
$ echo Hello > a/file1
$ git add a/file1
$ git commit -m 'Add file1'
$ git checkout -b fix
$ mkdir b
$ git mv a/file1 b
$ git commit -m 'Move file1 to b'
$ git checkout master
$ echo Bye > a/file2
$ git add a/file2
$ git commit -m 'Add file2'
$ git cherry-pick fix
[master 5b63afb] Move file1 to b
 Date: Wed Feb 27 13:27:45 2019 +0100
 2 files changed, 0 insertions(+), 0 deletions(-)
 rename {a => b}/file1 (100%)
 rename {a => b}/file2 (100%)

Regards
Linus Nilsson

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Phillip Wood]

Hi Linus

On 27/02/2019 12:47, Linus Nilsson wrote:
> Hi
> 
> I have found what I suspect to be a bug, or at least not desirable behavior in my case. In one branch, I have moved all files in a directory to another directory. The first directory is now empty in this branch (I haven't tested whether this is significant). 

I suspect that because you've moved all the files git thinks the 
directory has been renamed and that's why it moves a/file2 when fix is 
cherry-picked in the example below. I've cc'd Elijah as he knows more 
about how the directory rename detection works.

Best Wishes

Phillip

I cherry-picked the commit to another branch that has additional files 
in the first directory. All the files in the first directory are now 
moved to the second directory, and not just the files that were moved in 
the original commit. It happens in Git for Windows, versions 2.20.1 and 
2.21.0.
> 
> It can be reproduced using these steps:
> 
> $ git init
> $ mkdir a
> $ echo Hello > a/file1
> $ git add a/file1
> $ git commit -m 'Add file1'
> $ git checkout -b fix
> $ mkdir b
> $ git mv a/file1 b
> $ git commit -m 'Move file1 to b'
> $ git checkout master
> $ echo Bye > a/file2
> $ git add a/file2
> $ git commit -m 'Add file2'
> $ git cherry-pick fix
> [master 5b63afb] Move file1 to b
>   Date: Wed Feb 27 13:27:45 2019 +0100
>   2 files changed, 0 insertions(+), 0 deletions(-)
>   rename {a => b}/file1 (100%)
>   rename {a => b}/file2 (100%)
> 
> Regards
> Linus Nilsson
> 

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Elijah Newren]

Hi,

On Wed, Feb 27, 2019 at 6:30 AM Phillip Wood <phillip.wood123@gmail.com> wrote:
>
> Hi Linus
>
> On 27/02/2019 12:47, Linus Nilsson wrote:
> > Hi
> >
> > I have found what I suspect to be a bug, or at least not desirable behavior in my case. In one branch, I have moved all files in a directory to another directory. The first directory is now empty in this branch (I haven't tested whether this is significant).
>
> I suspect that because you've moved all the files git thinks the
> directory has been renamed and that's why it moves a/file2 when fix is
> cherry-picked in the example below. I've cc'd Elijah as he knows more
> about how the directory rename detection works.

Yes, Phillip is correct.  If the branch you were
merging/cherry-picking still had any files at all in the original
directory, then no directory rename would be detected.  You can read
up more details about how it works at
https://git.kernel.org/pub/scm/git/git.git/tree/Documentation/technical/directory-rename-detection.txt

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Jeff King]

On Wed, Feb 27, 2019 at 08:02:35AM -0800, Elijah Newren wrote:

> > > I have found what I suspect to be a bug, or at least not desirable
> > > behavior in my case. In one branch, I have moved all files in a
> > > directory to another directory. The first directory is now empty
> > > in this branch (I haven't tested whether this is significant).
> >
> > I suspect that because you've moved all the files git thinks the
> > directory has been renamed and that's why it moves a/file2 when fix is
> > cherry-picked in the example below. I've cc'd Elijah as he knows more
> > about how the directory rename detection works.
> 
> Yes, Phillip is correct.  If the branch you were
> merging/cherry-picking still had any files at all in the original
> directory, then no directory rename would be detected.  You can read
> up more details about how it works at
> https://git.kernel.org/pub/scm/git/git.git/tree/Documentation/technical/directory-rename-detection.txt

Is there a way to disable it (either by config, or for a single run)? I
know there's merge.renames, but it's plausible somebody might want
file-level renames but not directory-level ones.

-Peff

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Elijah Newren]

On Wed, Feb 27, 2019 at 8:40 AM Jeff King <peff@peff.net> wrote:
>
> On Wed, Feb 27, 2019 at 08:02:35AM -0800, Elijah Newren wrote:
>
> > > > I have found what I suspect to be a bug, or at least not desirable
> > > > behavior in my case. In one branch, I have moved all files in a
> > > > directory to another directory. The first directory is now empty
> > > > in this branch (I haven't tested whether this is significant).
> > >
> > > I suspect that because you've moved all the files git thinks the
> > > directory has been renamed and that's why it moves a/file2 when fix is
> > > cherry-picked in the example below. I've cc'd Elijah as he knows more
> > > about how the directory rename detection works.
> >
> > Yes, Phillip is correct.  If the branch you were
> > merging/cherry-picking still had any files at all in the original
> > directory, then no directory rename would be detected.  You can read
> > up more details about how it works at
> > https://git.kernel.org/pub/scm/git/git.git/tree/Documentation/technical/directory-rename-detection.txt
>
> Is there a way to disable it (either by config, or for a single run)? I
> know there's merge.renames, but it's plausible somebody might want
> file-level renames but not directory-level ones.
>
> -Peff

Not yet.  Adding such an option, similar in nature to the flags for
turning off renaming detection entirely (merge.renames, diff.renames,
-Xno-renames) would probably make sense (I don't see an analogy to
-Xrename-threshold=, though).  It might make sense as just an
alternate setting of merge.renames or diff.renames, though it's
possible that could get confusing with "copy" being an option.
#leftoverbits for someone that wants to figure out what the option
names and values should be?

RE: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Linus Nilsson]

Thanks for the answers. So it seems it's not a bug, but may lead to new merge options. I worked around it anyway, so it was not a real problem.

Med vänlig hälsning
Linus Nilsson

-----Original Message-----
From: Elijah Newren <newren@gmail.com> 
Sent: Wednesday, 27 February 2019 18:32
To: Jeff King <peff@peff.net>
Cc: Phillip Wood <phillip.wood@dunelm.org.uk>; Linus Nilsson <Linus.Nilsson@trimma.se>; git@vger.kernel.org
Subject: Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

On Wed, Feb 27, 2019 at 8:40 AM Jeff King <peff@peff.net> wrote:
>
> On Wed, Feb 27, 2019 at 08:02:35AM -0800, Elijah Newren wrote:
>
> > > > I have found what I suspect to be a bug, or at least not 
> > > > desirable behavior in my case. In one branch, I have moved all 
> > > > files in a directory to another directory. The first directory 
> > > > is now empty in this branch (I haven't tested whether this is significant).
> > >
> > > I suspect that because you've moved all the files git thinks the 
> > > directory has been renamed and that's why it moves a/file2 when 
> > > fix is cherry-picked in the example below. I've cc'd Elijah as he 
> > > knows more about how the directory rename detection works.
> >
> > Yes, Phillip is correct.  If the branch you were 
> > merging/cherry-picking still had any files at all in the original 
> > directory, then no directory rename would be detected.  You can read 
> > up more details about how it works at 
> > https://git.kernel.org/pub/scm/git/git.git/tree/Documentation/techni
> > cal/directory-rename-detection.txt
>
> Is there a way to disable it (either by config, or for a single run)? 
> I know there's merge.renames, but it's plausible somebody might want 
> file-level renames but not directory-level ones.
>
> -Peff

Not yet.  Adding such an option, similar in nature to the flags for turning off renaming detection entirely (merge.renames, diff.renames,
-Xno-renames) would probably make sense (I don't see an analogy to -Xrename-threshold=, though).  It might make sense as just an alternate setting of merge.renames or diff.renames, though it's possible that could get confusing with "copy" being an option.
#leftoverbits for someone that wants to figure out what the option names and values should be?

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Junio C Hamano]

As you know that I've always been skeptical to this rename-directory
business, this probably won't come as a surprise, but I seriously
think directory renames should be made opt-in, and as a separate
option, making the option three-way.  I.e.

 - do we do any renames (yes/no)?

 - if we do do renames, do we base the decision only on the contents
   of the thing along, or do we allow neighbouring files affect the
   decision?
 
That is, in addition to the traditional --renames or -M, we'd have a
separate bool --allow-directory-renames that is by default off and
is a no-op if the former is off.

We had to fix a breakage recently for 3-way fallback case, and we
explained the fix as needed because the case lacks the full
information, but I think even with the full information at hand, the
rename-directory heurisitcs is inherently riskier than the content
based rename detection.

Suppose you had F1, F2, ... in directory D1, and moved them all to
D1/D2.  In the meantime, somebody else adds Fn to directory D1.  It
may be likely that some variant of Fn would want to go to D1/D2, but
it also is very likely that there should be a difference between
D1/Fn somebody else had, and the contents of D1/D2/Fn in the merge
result.  Perhaps D1/F1 in your preimage used to refer to another
path in the top-level directory as "../top", but the reference would
have been rewritten to "../../top" when you moved D1/F1 to D1/D2/F1,
and the person doing the merge should at least check if D1/Fn that
comes from the other party needs a similar adjustment while merged.

In the above scenario, if there were D1/Fn in _your_ preimage and
all the other party did was to make in-place modification, the story
is vastly different.  Most likely you would have made most of, if
not all, the adjustment necessary for D1/Fn to sit in its new
location, while the other party kept the relative reference to other
places intact, so we can say that both parties have say in the
contents of the auto-merged result.  The "since neighgours moved,
this must also want to move the same way" heuristics does not give a
chance to the party that is not aware of the move to prepare the
contents appropriate for the new location, by definition, so the
onus is on the person who merges to adjust the contents.

Thanks.

[jch: I am still mostly offline til the next week, but I had a
chance to sit in front of my mailbox long enough, so...]

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Elijah Newren]

Hi Junio,

On Thu, Feb 28, 2019 at 6:52 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> As you know that I've always been skeptical to this rename-directory
> business, this probably won't come as a surprise, but I seriously
> think directory renames should be made opt-in, and as a separate
> option, making the option three-way.  I.e.
>
>  - do we do any renames (yes/no)?
>
>  - if we do do renames, do we base the decision only on the contents
>    of the thing along, or do we allow neighbouring files affect the
>    decision?
>
> That is, in addition to the traditional --renames or -M, we'd have a
> separate bool --allow-directory-renames that is by default off and
> is a no-op if the former is off.

We've gone from always-off (ability wasn't implemented), to always on
(assuming normal rename detection was on), and now we're considering
making it an option, with you proposing opt-in.  While I think opt-out
would be a better default, we may want to first consider the range of
possibilities; if more safety is needed, other choices might be safer
than either opt-in or opt-out.

This email reminds me a bit of the recent overlay discussion, where
some of your wording made me think about directory handling, but you
had smudge filters in mind.  We're occasionally on different
wavelengths, and I'm worried I might be mis-reading your main point
and/or that my responses only address part of the issues you have in
mind.  Let me know if that's the case.

> We had to fix a breakage recently for 3-way fallback case, and we
> explained the fix as needed because the case lacks the full
> information, but I think even with the full information at hand, the
> rename-directory heurisitcs is inherently riskier than the content
> based rename detection.
>
> Suppose you had F1, F2, ... in directory D1, and moved them all to
> D1/D2.  In the meantime, somebody else adds Fn to directory D1.  It
> may be likely that some variant of Fn would want to go to D1/D2, but
> it also is very likely that there should be a difference between
> D1/Fn somebody else had, and the contents of D1/D2/Fn in the merge
> result.  Perhaps D1/F1 in your preimage used to refer to another
> path in the top-level directory as "../top", but the reference would
> have been rewritten to "../../top" when you moved D1/F1 to D1/D2/F1,
> and the person doing the merge should at least check if D1/Fn that
> comes from the other party needs a similar adjustment while merged.
>
> In the above scenario, if there were D1/Fn in _your_ preimage and
> all the other party did was to make in-place modification, the story
> is vastly different.  Most likely you would have made most of, if
> not all, the adjustment necessary for D1/Fn to sit in its new
> location, while the other party kept the relative reference to other
> places intact, so we can say that both parties have say in the
> contents of the auto-merged result.  The "since neighgours moved,
> this must also want to move the same way" heuristics does not give a
> chance to the party that is not aware of the move to prepare the
> contents appropriate for the new location, by definition, so the
> onus is on the person who merges to adjust the contents.

There are a few issues here to unpack.

First, in regards to your example, the very first "Limitation" imposed
by the directory rename heuristics was:
  * If a given directory still exists on both sides of a merge, we do
not consider it to have been renamed.
Therefore, your (detailed) example above of "renaming" D1/* to D1/D2/*
isn't something the directory rename heuristics supports (the presence
of D1/D2/ implies D1/ still exists and thus could not have been
renamed; this particular case is explicitly mentioned in t6043 and I
brought it up a couple times during the review of the directory rename
patch series with Stefan).  There are too many edge/corner cases that
become difficult without this rule and it was considered more likely
to (negatively) surprise users, so even with directory rename
heuristics on, a new file Fn added to D1/ on the other side of the
merge will remain in D1/Fn after the merge.  Perhaps this
clarification helps assuage your worries, or maybe your example was an
unfortunate one for relaying your real underlying concern.

Second, you stated that you thought "rename-directory [heuristics are]
inherently riskier" than not having them on, and then gave a single
(though involved) example.  This could be read to imply that you
believe directory rename heuristics are for convenience only, that
there is no risk involved with not detecting directory renames, and
thus all that matters is the cost benefit of the convenience of
detecting renames for users vs. whatever risks there are in
"detecting" renames that aren't actually wanted by users.  I do not
know if you intended any of these implications at all, but I do want
to point out that not detecting directory renames is not merely a
convenience.  While that convenience was _part_ of the reason spurring
my work on that capability, it was also pushed due to my having been
told about bugs caused by not having it.  I don't remember the details
I was told (and I wasn't even told the full details of the bugs), but
my understanding and/or guesses years later is:
  * build systems sometimes build code according to directories and globs
  * an un-detected directory rename can thus cause new files on one
side of history to not get built as expected
  * other files may not have direct references to identifiers in the
new files, thus no compilation-time or link-time failures occur
  * the new code could have had a static singleton that registered
itself with some other logic in the code
  * the "other logic" rather than having a one-to-one set of handlers
may have a priority listing of which static singletons to use
  * therefore, there is no runtime failure from failing to compile the
code either, just different behavior than expected
  * a testcase should have caught this type of problem anyway, but
testcases aren't always added
  * it was a rarely used, but important case
  * the developer did *manually* test this pretty carefully...but
didn't expect a "clean merge" to break things.  :-(
  * this kind of issue might not be detected before release,
deployment, or installation and usage at a customer site.
  * testcases are a best practice for a reason, it was totally our
fault for missing them, but having multiple LTS releases and large
code directory refactors between versions increased the odds we'd
eventually hit failures of this type

Third, at the end of your example, you say that the rename-directory
heuristics "[puts the onus] on the person who merges to adjust the
contents", but my example above shows the same is true if directory
renaming is turned off.  The person doing the merge needs to somehow
know there may have been a directory rename and possibly move files
and update references or things may have semantic breaks.  This seems
no different to me than normal content merges with e.g. new
invocations of a function added on one side of history and on the
other side of history new parameters added to the function call
signature.  Actually, I guess there is one difference: we have a way
of detecting the (potential) directory rename and notifying the user
of a possible change -- though we haven't taken advantage of this
possibility yet (handle_rename_via_dir() silently moves files).

Perhaps, though, you see directory rename heuristics as somehow
riskier than semantic merge conflicts of other types, and perhaps we
should add more options here.  But I think there are other possible
solutions here which are worthy of consideration before choosing which
behavior we want.  Thinking just in terms of the default behavior,
here are eight possibilities:
  * leave the capability on with no changes (no ability to opt-out,
other than turning rename detection off entirely)
  * remove the directory rename detection capability entirely (go back
to pre- git-2.18 behavior)
  * opt-out (let users choose pre-git-2.18 behavior, but default to
silently moving files according to directory rename heuristics)
  * opt-in (directory rename detection is off by default and users are
given no notice that paths should perhaps be renamed)
  * display messages whenever directory rename detection adjusts a path location
  * display messages whenever directory rename detection could adjust
a path location, but don't adjust it
  * whenever directory rename detection adjusts a path location, mark
the new path as conflicted (i.e. record at either stage 2 or 3 instead
of 0)
  * whenever directory rename detection would adjust a path, leave it
where it was but mark it as conflicted, and print a helpful message

Whatever we choose for the default could be tweaked by some new option
(e.g. make it less noisy or don't mark such paths as conflicted if the
user has explicitly stated their preference for or against directory
rename detection).  I'm struggling to see directory rename detection
as "risky" (though I certainly feel that lack of it is and thus do not
like the opt-in option), but if others feel there is risk here,
wouldn't one of the last four options be safer than Peff's suggestion
of opt-out or your suggestion of opt-in?


Thanks,
Elijah

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Junio C Hamano]

Elijah Newren <newren@gmail.com> writes:

> Whatever we choose for the default could be tweaked by some new option
> (e.g. make it less noisy or don't mark such paths as conflicted if the
> user has explicitly stated their preference for or against directory
> rename detection).  I'm struggling to see directory rename detection
> as "risky" (though I certainly feel that lack of it is and thus do not
> like the opt-in option), but if others feel there is risk here,

I do not think it matters what "others feel" at all.

The simple fact that we are seeing a bug report that started this
thread is enough to say that the heuristics kick in when the end
users do not expect to and when it happens it is harder to explain
than other kinds of rename detection heuristics.

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Elijah Newren]

On Sat, Mar 2, 2019 at 5:33 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> Elijah Newren <newren@gmail.com> writes:
>
> > Whatever we choose for the default could be tweaked by some new option
> > (e.g. make it less noisy or don't mark such paths as conflicted if the
> > user has explicitly stated their preference for or against directory
> > rename detection).  I'm struggling to see directory rename detection
> > as "risky" (though I certainly feel that lack of it is and thus do not
> > like the opt-in option), but if others feel there is risk here,
>
> I do not think it matters what "others feel" at all.
>
> The simple fact that we are seeing a bug report that started this
> thread is enough to say that the heuristics kick in when the end
> users do not expect to and when it happens it is harder to explain
> than other kinds of rename detection heuristics.
>

Alright, here is a patch to change the default, explaining the history
and updating t6043 (directory rename tests) accordingly.

The following patch does not apply to master, due to building on
jk/unused-params; let me know if you want to see a backport.  I built
on jk/unused-params and partially reverted one of its patches (because
now there is a use for one of the parameters it removed), so that it
could apply cleanly to next and pu.


-- 8< --
Subject: [PATCH] merge-recursive: switch directory rename detection default

When all of x/a, x/b, and x/c have moved to z/a, z/b, and z/c on one
branch, there is a question about whether x/d added on a different
branch should remain at x/d or appear at z/d when the two branches are
merged.  There are different possible viewpoints here:

  A) The file was placed at x/d; it's unrelated to the other files in
     x/ so it doesn't matter that all the files from x/ moved to z/ on
     one branch; x/d should still remain at x/d.

  B) x/d is related to the other files in x/, and x/ was renamed to z/;
     therefore x/d should be moved to z/d.

Since there was no ability to detect directory renames prior to
git-2.18, users experienced (A) regardless of context.  Choice (B) was
implemented in git-2.18, with no option to go back to (A), and has been
in use since.  However, one user reported that the merge results did not
match their expectations, making the change of default problematic,
especially since there was no notice printed when directory rename
detection moved files.

Note that there is also a third possibility here:

  C) There are different answers depending on the context and content
     that cannot be determined by git, so this is a conflict.  Use a
     higher stage in the index to record the conflict and notify the
     user of the potential issue instead of silently selecting a
     resolution for them.

Add an option for users to specify their preference for whether to use
directory rename detection, and default to (C).

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 Documentation/config/merge.txt      |  19 +++-
 merge-recursive.c                   |  83 +++++++++-----
 t/t3401-rebase-and-am-rename.sh     |   8 +-
 t/t6043-merge-rename-directories.sh | 171 +++++++++++++++++++---------
 4 files changed, 195 insertions(+), 86 deletions(-)

diff --git a/Documentation/config/merge.txt b/Documentation/config/merge.txt
index d389c73929..6a313937f8 100644
--- a/Documentation/config/merge.txt
+++ b/Documentation/config/merge.txt
@@ -39,9 +39,22 @@ merge.renameLimit::
 	is turned off.
 
 merge.renames::
-	Whether and how Git detects renames.  If set to "false",
-	rename detection is disabled. If set to "true", basic rename
-	detection is enabled.  Defaults to the value of diff.renames.
+	Whether Git detects renames.  If set to "false", rename detection
+	is disabled. If set to "true", basic rename detection is enabled.
+	Defaults to the value of diff.renames.
+
+merge.directoryRenames::
+	Whether Git detects directory renames, affecting what happens at
+	merge time to new files added to a directory on one side of
+	history when that directory was renamed on the other side of
+	history.  If merge.directoryRenames is set to "false", directory
+	rename detection is disabled, meaning that such new files will be
+	left behind in the old directory.  If set to "true", directory
+	rename detection is enabled, meaning that such new files will be
+	moved into the new directory.  If set to "conflict", a conflict
+	will be reported for such paths.  If merge.renames is false,
+	merge.directoryRenames is ignored and treated as false.  Defaults
+	to "conflict".
 
 merge.renormalize::
 	Tell Git that canonical representation of files in the
diff --git a/merge-recursive.c b/merge-recursive.c
index f270fa66f3..042548eeec 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1402,39 +1402,62 @@ static int merge_mode_and_contents(struct merge_options *o,
 
 static int handle_rename_via_dir(struct merge_options *o,
 				 struct diff_filepair *pair,
-				 const char *rename_branch)
+				 const char *rename_branch,
+				 const char *other_branch)
 {
 	/*
 	 * Handle file adds that need to be renamed due to directory rename
-	 * detection.  This differs from handle_rename_normal, because
-	 * there is no content merge to do; just move the file into the
-	 * desired final location.
+	 * detection, based on the setting of o->detect_directory_renames:
+	 *   o->detect_directory_renames == 0: never use directory renames
+	 *   o->detect_directory_renames == 1: report directory conflict
+	 *   o->detect_directory_renames == 2: always use directory renames
+	 * However, this function will not even be called when the value is
+	 * 0, so we only have to worry about values of 1 and 2.
+	 *
+	 * This function differs from handle_rename_normal, because there
+	 * is no content merge to do; we can just mark the file as
+	 * conflicted and/or move the file into the desired final location.
 	 */
 	const struct diff_filespec *dest = pair->two;
-
+	char *file_path = dest->path;
+	int mark_conflicted = (o->detect_directory_renames == 1);
+
+	if (mark_conflicted)
+		output(o, 1, _("CONFLICT (directory possibly renamed): %s "
+			       "added in %s, but that directory was renamed "
+			       "in %s suggesting it should perhaps be moved "
+			       "to %s."),
+		       pair->one->path, other_branch, rename_branch,
+		       dest->path);
 	if (!o->call_depth && would_lose_untracked(o, dest->path)) {
-		char *alt_path = unique_path(o, dest->path, rename_branch);
-
+		mark_conflicted = 1;
+		file_path = unique_path(o, dest->path, rename_branch);
 		output(o, 1, _("Error: Refusing to lose untracked file at %s; "
 			       "writing to %s instead."),
-		       dest->path, alt_path);
+		       dest->path, file_path);
+	}
+
+	if (mark_conflicted) {
 		/*
-		 * Write the file in worktree at alt_path, but not in the
-		 * index.  Instead, write to dest->path for the index but
-		 * only at the higher appropriate stage.
+		 * Write the file in worktree at file_path.  In the index,
+		 * only record the file at dest->path in the appropriate
+		 * higher stage.
 		 */
-		if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
+		if (update_file(o, 0, &dest->oid, dest->mode, file_path))
 			return -1;
-		free(alt_path);
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		if (update_stages(o, dest->path, NULL,
+				  rename_branch == o->branch1 ? dest : NULL,
+				  rename_branch == o->branch1 ? NULL : dest))
+			return -1;
+		if (file_path != dest->path)
+			free(file_path);
+		return 0; /* not clean, but conflicted */
+	} else {
+		/* Update dest->path both in index and in worktree */
+		if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
+			return -1;
+		return 1; /* clean */
 	}
-
-	/* Update dest->path both in index and in worktree */
-	if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
-		return -1;
-	return 0;
 }
 
 static int handle_change_delete(struct merge_options *o,
@@ -3261,11 +3284,10 @@ static int process_entry(struct merge_options *o,
 							   conflict_info);
 			break;
 		case RENAME_VIA_DIR:
-			clean_merge = 1;
-			if (handle_rename_via_dir(o,
-						  conflict_info->pair1,
-						  conflict_info->branch1))
-				clean_merge = -1;
+			clean_merge = handle_rename_via_dir(o,
+							    conflict_info->pair1,
+							    conflict_info->branch1,
+							    conflict_info->branch2);
 			break;
 		case RENAME_ADD:
 			/*
@@ -3681,6 +3703,15 @@ static void merge_recursive_config(struct merge_options *o)
 		o->merge_detect_rename = git_config_rename("merge.renames", value);
 		free(value);
 	}
+	if (!git_config_get_string("merge.directoryrenames", &value)) {
+		if (!strcasecmp(value, "true"))
+			o->detect_directory_renames = 2;
+		if (!strcasecmp(value, "false"))
+			o->detect_directory_renames = 0;
+		if (!strcasecmp(value, "conflict"))
+			o->detect_directory_renames = 1;
+		free(value);
+	}
 	git_config(git_xmerge_config, NULL);
 }
 
diff --git a/t/t3401-rebase-and-am-rename.sh b/t/t3401-rebase-and-am-rename.sh
index e0b5111993..a0b9438b22 100755
--- a/t/t3401-rebase-and-am-rename.sh
+++ b/t/t3401-rebase-and-am-rename.sh
@@ -42,7 +42,7 @@ test_expect_success 'rebase --interactive: directory rename detected' '
 		git checkout B^0 &&
 
 		set_fake_editor &&
-		FAKE_LINES="1" git rebase --interactive A &&
+		FAKE_LINES="1" git -c merge.directoryRenames=true rebase --interactive A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -58,7 +58,7 @@ test_expect_failure 'rebase (am): directory rename detected' '
 
 		git checkout B^0 &&
 
-		git rebase A &&
+		git -c merge.directoryRenames=true rebase A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -74,7 +74,7 @@ test_expect_success 'rebase --merge: directory rename detected' '
 
 		git checkout B^0 &&
 
-		git rebase --merge A &&
+		git -c merge.directoryRenames=true rebase --merge A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -92,7 +92,7 @@ test_expect_failure 'am: directory rename detected' '
 
 		git format-patch -1 B &&
 
-		git am --3way 0001*.patch &&
+		git -c merge.directoryRenames=true am --3way 0001*.patch &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
index 62c564707b..1048ec2cac 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6043-merge-rename-directories.sh
@@ -75,7 +75,7 @@ test_expect_success '1a-check: Simple directory rename detection' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -142,7 +142,7 @@ test_expect_success '1b-check: Merge a directory with another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -201,7 +201,7 @@ test_expect_success '1c-check: Transitive renaming' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -270,7 +270,7 @@ test_expect_success '1d-check: Directory renames cause a rename/rename(2to1) con
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 
 		git ls-files -s >out &&
@@ -350,7 +350,7 @@ test_expect_success '1e-check: Renamed directory, with all files being renamed t
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -416,7 +416,7 @@ test_expect_success '1f-check: Split a directory into two other directories' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -497,7 +497,7 @@ test_expect_success '2a-check: Directory split into two on one side, with equal
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT.*directory rename split" out &&
 
 		git ls-files -s >out &&
@@ -559,7 +559,7 @@ test_expect_success '2b-check: Directory split into two on one side, with equal
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -640,7 +640,7 @@ test_expect_success '3a-check: Avoid implicit rename if involved as source on ot
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -705,7 +705,7 @@ test_expect_success '3b-check: Avoid implicit rename if involved as source on cu
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/d.*x/d.*w/d out &&
 		test_i18ngrep ! CONFLICT.*rename/rename.*y/d out &&
 
@@ -826,7 +826,7 @@ test_expect_success '4a-check: Directory split, with original directory still pr
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -915,7 +915,7 @@ test_expect_success '5a-check: Merge directories, other side adds files to origi
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT.*implicit dir rename" out &&
 
 		git ls-files -s >out &&
@@ -989,7 +989,7 @@ test_expect_success '5b-check: Rename/delete in order to get add/add/add conflic
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
 
 		git ls-files -s >out &&
@@ -1069,7 +1069,7 @@ test_expect_success '5c-check: Transitive rename would cause rename/rename/renam
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*z/d" out &&
 		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
 
@@ -1153,7 +1153,7 @@ test_expect_success '5d-check: Directory/file/file conflict due to directory ren
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (file/directory).*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1243,7 +1243,7 @@ test_expect_success '6a-check: Tricky rename/delete' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*z/c.*y/c" out &&
 
 		git ls-files -s >out &&
@@ -1308,7 +1308,7 @@ test_expect_success '6b-check: Same rename done on both sides' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1370,7 +1370,7 @@ test_expect_success '6c-check: Rename only done on same side' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1432,7 +1432,7 @@ test_expect_success '6d-check: We do not always want transitive renaming' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1495,7 +1495,7 @@ test_expect_success '6e-check: Add/add from one side' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -1591,7 +1591,7 @@ test_expect_success '7a-check: rename-dir vs. rename-dir (NOT split evenly) PLUS
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*z/b.*y/b.*w/b" out &&
 		test_i18ngrep "CONFLICT (rename/rename).*z/c.*y/c.*x/c" out &&
 
@@ -1663,7 +1663,7 @@ test_expect_success '7b-check: rename/rename(2to1), but only due to transitive r
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 
 		git ls-files -s >out &&
@@ -1740,7 +1740,7 @@ test_expect_success '7c-check: rename/rename(1to...2or3); transitive rename may
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1804,7 +1804,7 @@ test_expect_success '7d-check: transitive rename involved in rename/delete; how
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1894,7 +1894,7 @@ test_expect_success '7e-check: transitive rename in rename/delete AND dirs in th
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1985,7 +1985,7 @@ test_expect_success '8a-check: Dual-directory rename, one into the others way' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -2063,7 +2063,7 @@ test_expect_success '8b-check: Dual-directory rename, one into the others way, w
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -2135,7 +2135,7 @@ test_expect_success '8c-check: modify/delete or rename+modify/delete' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (modify/delete).* z/d" out &&
 
 		git ls-files -s >out &&
@@ -2212,7 +2212,7 @@ test_expect_success '8d-check: rename/delete...or not?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2287,7 +2287,7 @@ test_expect_success '8e-check: Both sides rename, one side adds to original dire
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/c.*y/c.*w/c out &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/b.*y/b.*w/b out &&
 
@@ -2374,7 +2374,7 @@ test_expect_success '9a-check: Inner renamed directory within outer renamed dire
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 7 out &&
@@ -2444,7 +2444,7 @@ test_expect_success '9b-check: Transitive rename with content merge' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2534,7 +2534,7 @@ test_expect_success '9c-check: Doubly transitive rename?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "WARNING: Avoiding applying x -> z rename to x/f" out &&
 
 		git ls-files -s >out &&
@@ -2622,7 +2622,7 @@ test_expect_success '9d-check: N-way transitive rename?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "WARNING: Avoiding applying z -> y rename to z/t" out &&
 		test_i18ngrep "WARNING: Avoiding applying y -> x rename to y/a" out &&
 		test_i18ngrep "WARNING: Avoiding applying x -> w rename to x/b" out &&
@@ -2704,7 +2704,7 @@ test_expect_success C_LOCALE_OUTPUT '9e-check: N-to-1 whammo' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		grep "CONFLICT (implicit dir rename): Cannot map more than one path to combined/yo" out >error_line &&
 		grep -q dir1/yo error_line &&
 		grep -q dir2/yo error_line &&
@@ -2782,7 +2782,7 @@ test_expect_success '9f-check: Renamed directory that only contained immediate s
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2849,7 +2849,7 @@ test_expect_failure '9g-check: Renamed directory that only contained immediate s
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2918,7 +2918,7 @@ test_expect_success '9h-check: Avoid dir rename on merely modified path' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2993,7 +2993,7 @@ test_expect_success '10a-check: Overwrite untracked with normal rename/delete' '
 		echo very >z/c &&
 		echo important >z/d &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "The following untracked working tree files would be overwritten by merge" err &&
 
 		git ls-files -s >out &&
@@ -3061,7 +3061,7 @@ test_expect_success '10b-check: Overwrite untracked with dir rename + delete' '
 		echo important >y/d &&
 		echo contents >y/e &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/delete).*Version B\^0 of y/d left in tree at y/d~B\^0" out &&
 		test_i18ngrep "Error: Refusing to lose untracked file at y/e; writing to y/e~B\^0 instead" out &&
 
@@ -3137,7 +3137,7 @@ test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)
 		git checkout A^0 &&
 		echo important >y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~B\^0 instead" out &&
 
@@ -3174,7 +3174,7 @@ test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)
 		mkdir y &&
 		echo important >y/c &&
 
-		test_must_fail git merge -s recursive A^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~HEAD instead" out &&
 
@@ -3249,7 +3249,7 @@ test_expect_success '10d-check: Delete untracked with dir rename/rename(2to1)' '
 		git checkout A^0 &&
 		echo important >y/wham &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/wham" out &&
 
@@ -3327,7 +3327,7 @@ test_expect_failure '10e-check: Does git complain about untracked file that is n
 		mkdir z &&
 		echo random >z/c &&
 
-		git merge -s recursive B^0 >out 2>err &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep ! "following untracked working tree files would be overwritten by merge" err &&
 
 		git ls-files -s >out &&
@@ -3407,7 +3407,7 @@ test_expect_success '11a-check: Avoid losing dirty contents with simple rename'
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		test_seq 1 10 >expected &&
@@ -3479,7 +3479,7 @@ test_expect_success '11b-check: Avoid losing dirty file involved in directory re
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		git merge -s recursive B^0 >out 2>err &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		grep -q stuff z/c &&
@@ -3554,7 +3554,7 @@ test_expect_success '11c-check: Avoid losing not-uptodate with rename + D/F conf
 		git checkout A^0 &&
 		echo stuff >>y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "following files would be overwritten by merge" err &&
 
 		grep -q stuff y/c &&
@@ -3621,7 +3621,7 @@ test_expect_success '11d-check: Avoid losing not-uptodate with rename + D/F conf
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		grep -q stuff z/c &&
@@ -3700,7 +3700,7 @@ test_expect_success '11e-check: Avoid deleting not-uptodate with dir rename/rena
 		git checkout A^0 &&
 		echo mods >>y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose dirty file at y/c" out &&
 
@@ -3782,7 +3782,7 @@ test_expect_success '11f-check: Avoid deleting not-uptodate with dir rename/rena
 		git checkout A^0 &&
 		echo important >>y/wham &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose dirty file at y/wham" out &&
 
@@ -3870,7 +3870,7 @@ test_expect_success '12a-check: Moving one directory hierarchy into another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -3946,7 +3946,7 @@ test_expect_success '12b-check: Moving one directory hierarchy into another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -4016,7 +4016,7 @@ test_expect_success '12c-check: Moving one directory hierarchy into another w/ c
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -u >out &&
 		test_line_count = 12 out &&
@@ -4051,4 +4051,69 @@ test_expect_success '12c-check: Moving one directory hierarchy into another w/ c
 	)
 '
 
+# Testcase 12d, Basic directory rename with default "conflict" setting
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d,e/f}
+#   Expected: y/{b,c,d,e/f}, with both y/d and y/e/f marked as conflicted
+
+test_expect_success '12d-setup: Conflict handling for default setting' '
+	test_create_repo 12d &&
+	(
+		cd 12d &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo d >z/d &&
+		mkdir z/e &&
+		echo f >z/e/f &&
+		git add z/d z/e/f &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '12d-check: Conflict handling for default setting' '
+	(
+		cd 12d &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c :3:y/d :3:y/e/f &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:z/d    B:z/e/f &&
+		test_cmp expect actual &&
+
+		git hash-object y/d >actual &&
+		git rev-parse B:z/d >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:z/d &&
+		test_must_fail git rev-parse HEAD:z/e/f &&
+		test_path_is_missing z/d &&
+		test_path_is_missing z/e/f
+	)
+'
+
 test_done
-- 
2.21.0.rc1.19.g5671d8e416

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Junio C Hamano]

Elijah Newren <newren@gmail.com> writes:

> Note that there is also a third possibility here:
>
>   C) There are different answers depending on the context and content
>      that cannot be determined by git, so this is a conflict.  Use a
>      higher stage in the index to record the conflict and notify the
>      user of the potential issue instead of silently selecting a
>      resolution for them.
>
> Add an option for users to specify their preference for whether to use
> directory rename detection, and default to (C).

Yeah, (c) is the sanest default that can give the best of both
worlds, I would have to say.

Sometimes the heuristics guess that the new one may want to go to
the same place as all the neighbours, and other times the new one
may want to stay.  By using stage #2 and stage #3 appropriately, the
user can see where the final result wants to be in.  Because by
definition there won't be any auto-resolvable content-level merge
for such paths (after all, one side is adding it as a new file), I
think the contents for these two higher-stage entries would actually
be the same?

> +	if (mark_conflicted)
> +		output(o, 1, _("CONFLICT (directory possibly renamed): %s "
> +			       "added in %s, but that directory was renamed "
> +			       "in %s suggesting it should perhaps be moved "
> +			       "to %s."),
> +		       pair->one->path, other_branch, rename_branch,
> +		       dest->path);

What confused the end user is that it is not always the case, and
that is because the only thing we know at this point is that the
other branch moved all the files in that directory in their branch
to the other place, not that they "moved the directory".

In other words, if "that directory was renamed" in this message were
definitive and agreed with end-user perception, we won't be issuing
this conflict with a label that says "possibly" renamed.

Perhaps something along this line?

	%(pair->one->path)s added in %(other_branch)s, but the other
	branch %(rename_branch)s moved all the files in the same
	directory to %(dirname(dest->path))s, so this file may also
	want to move there, too.

>  	if (!o->call_depth && would_lose_untracked(o, dest->path)) {
> -		char *alt_path = unique_path(o, dest->path, rename_branch);
> -
> +		mark_conflicted = 1;
> +		file_path = unique_path(o, dest->path, rename_branch);
>  		output(o, 1, _("Error: Refusing to lose untracked file at %s; "
>  			       "writing to %s instead."),
> -		       dest->path, alt_path);
> +		       dest->path, file_path);
> +	}
> +
> +	if (mark_conflicted) {
>  		/*
> -		 * Write the file in worktree at alt_path, but not in the
> -		 * index.  Instead, write to dest->path for the index but
> -		 * only at the higher appropriate stage.
> +		 * Write the file in worktree at file_path.  In the index,
> +		 * only record the file at dest->path in the appropriate
> +		 * higher stage.
>  		 */
> -		if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
> +		if (update_file(o, 0, &dest->oid, dest->mode, file_path))
>  			return -1;
> +		if (update_stages(o, dest->path, NULL,
> +				  rename_branch == o->branch1 ? dest : NULL,
> +				  rename_branch == o->branch1 ? NULL : dest))
> +			return -1;

This one does not issue "may want to stay here" comment of its own,
so the earlier "CONFLICT (directory possibly renamed)" message would
need to cover both of these two higher-stage entries.  I think the
message mentions the two paths, so it would be good already.

The earlier "CONFLICT (directory possibly renamed)" message may be
sufficient to explain the situation, but I wonder if the user would
need hints in resolving either of the two possible ways.  I do not
know if it should be in the same message, or in the manpage update,
but first let's make sure what we want the end users to understand.
IIUC, the hint for resolving in favor of either would be to do these
two commands?

	git checkout --ours $path_the_user_wants_to_use
	git rm --cached $the_other_path

If the path the user wants to use matches what the branch being
merged has, then replace "--ours" above with "--theirs".

Would that be a good explanation?

Regarding the implementation (not the use of stages, but how
"mark_conflicted" variable gets used), I am not sure if I agree that
only choice (c) should give the hint.  Regardless of the settings,
we know both paths this file may want to end up with, and I suspect
that the alternative a/b/c you gave are how by default the tool
automatically places the result, giving a chance to the end user to
correct mistakes.  I wonder if it is possible to somehow show "the
other possibilty" in the merge log even when choice (a) or (b) are
in effect?  E.g. "path X/B moved to Y/B because the other side moved
X/A to Y/A" when choice (b) is in use, and "path X/B kept there but
the other side moved neighbouring A/X to Y/A" when choice (a) is in
use.

Another thing that makes me wonder is if this should be treated
similar to rerere.autoupdate; even when rerere kicks in to resolve
otherwise conflicting tricky merge, without being explicitly allowed
with the config, it does not register the resolution to the index at
stage #0.  Either choices (a) that ignores neighbouring files'
movement or (b) that follows the movement lets this tricky
heuristics not just suggest the end result, but allows it to
register the result at stage #0, which somehow feels too aggressive
(which was what triggered my suggestion to go with (c)).  With that
attitude, we may be able to get rid of choice (a) altogether, which
may make things a tad simpler.  IOW, we assume the heuristics would
suggest the right solution most of the time, just like we assume
rerere gives a reasonable resolution most of the time, with a knob
to accept the result blindly, together with hints to recover when
heuristics makes mistakes.

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Elijah Newren]

On Tue, Mar 5, 2019 at 8:43 PM Junio C Hamano <gitster@pobox.com> wrote:
> Elijah Newren <newren@gmail.com> writes:
>
> > Note that there is also a third possibility here:
> >
> >   C) There are different answers depending on the context and content
> >      that cannot be determined by git, so this is a conflict.  Use a
> >      higher stage in the index to record the conflict and notify the
> >      user of the potential issue instead of silently selecting a
> >      resolution for them.
> >
> > Add an option for users to specify their preference for whether to use
> > directory rename detection, and default to (C).
>
> Yeah, (c) is the sanest default that can give the best of both
> worlds, I would have to say.

Great, sounds like we're in agreement on the high level objective.  :-)

> Sometimes the heuristics guess that the new one may want to go to
> the same place as all the neighbours, and other times the new one
> may want to stay.  By using stage #2 and stage #3 appropriately, the
> user can see where the final result wants to be in.  Because by
> definition there won't be any auto-resolvable content-level merge
> for such paths (after all, one side is adding it as a new file), I
> think the contents for these two higher-stage entries would actually
> be the same?

I'm not sure I'm following well enough to answer any your question(s),
so I'll instead ask a few of my own:
  * Are you referring to stage #2 and stage #3 of the old path or the
new path or one of each or both of each?
  * Would this be consistent with how normal renames behave?
and, as a partial answer to your question:
  * Does that also work with files renamed into the old directory
instead of just added?

I don't know if normal renames are similar enough to the directory
rename case in this particular area that it makes sense to compare,
but there was one specific thing that came to my mind that I wondered
about:  For normal renames, we only have index entries for the new
path rather than the old path even if there are content level merge
conflicts.  So, for example if a 'list_of_favorites.txt' was modified
on both sides of history and one side renames to
$SUBDIR/list_of_favorites.txt, then instead of having any entries in
the index for list_of_favorites.txt, we have three entries for
$SUBDIR/list_of_favorites.txt.  That makes it easier for users to
resolve (they can use a single git add and no git rm).

Note that as a special case for this rename, we could have $SUBDIR/ =
x/, because if the other side renamed x/ -> z/, then
list_of_favorites.txt should perhaps be transitively renamed to
z/list_of_favorites.txt.  Although this kind of thing is more rare
than just adding files to the old directory, this kind of case comes
up too, so there actually could be content-level merge for paths
affected by directory rename detection.  (Sidenote more for myself:
Transitively renamed paths feed through handle_rename_normal() instead
of handle_rename_via_dir(), so I need to add the new conflict/warning
messages to handle_rename_normal() too.)

> > +     if (mark_conflicted)
> > +             output(o, 1, _("CONFLICT (directory possibly renamed): %s "
> > +                            "added in %s, but that directory was renamed "
> > +                            "in %s suggesting it should perhaps be moved "
> > +                            "to %s."),
> > +                    pair->one->path, other_branch, rename_branch,
> > +                    dest->path);
>
> What confused the end user is that it is not always the case, and
> that is because the only thing we know at this point is that the
> other branch moved all the files in that directory in their branch
> to the other place, not that they "moved the directory".
>
> In other words, if "that directory was renamed" in this message were
> definitive and agreed with end-user perception, we won't be issuing
> this conflict with a label that says "possibly" renamed.
>
> Perhaps something along this line?
>
>         %(pair->one->path)s added in %(other_branch)s, but the other
>         branch %(rename_branch)s moved all the files in the same
>         directory to %(dirname(dest->path))s, so this file may also
>         want to move there, too.

That sounds better, thanks.  A follow-up question: We normally have
conflict messages of the form:
    CONFLICT(<summary>): <long description>
You've provided an improved long description, but do you have a
suggestion for the summary?  "path location"?  "directory possibly
renamed"?  Something else?

> >       if (!o->call_depth && would_lose_untracked(o, dest->path)) {
> > -             char *alt_path = unique_path(o, dest->path, rename_branch);
> > -
> > +             mark_conflicted = 1;
> > +             file_path = unique_path(o, dest->path, rename_branch);
> >               output(o, 1, _("Error: Refusing to lose untracked file at %s; "
> >                              "writing to %s instead."),
> > -                    dest->path, alt_path);
> > +                    dest->path, file_path);
> > +     }
> > +
> > +     if (mark_conflicted) {
> >               /*
> > -              * Write the file in worktree at alt_path, but not in the
> > -              * index.  Instead, write to dest->path for the index but
> > -              * only at the higher appropriate stage.
> > +              * Write the file in worktree at file_path.  In the index,
> > +              * only record the file at dest->path in the appropriate
> > +              * higher stage.
> >                */
> > -             if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
> > +             if (update_file(o, 0, &dest->oid, dest->mode, file_path))
> >                       return -1;
> > +             if (update_stages(o, dest->path, NULL,
> > +                               rename_branch == o->branch1 ? dest : NULL,
> > +                               rename_branch == o->branch1 ? NULL : dest))
> > +                     return -1;
>
> This one does not issue "may want to stay here" comment of its own,
> so the earlier "CONFLICT (directory possibly renamed)" message would
> need to cover both of these two higher-stage entries.  I think the
> message mentions the two paths, so it would be good already.
>
> The earlier "CONFLICT (directory possibly renamed)" message may be
> sufficient to explain the situation, but I wonder if the user would
> need hints in resolving either of the two possible ways.  I do not
> know if it should be in the same message, or in the manpage update,
> but first let's make sure what we want the end users to understand.
> IIUC, the hint for resolving in favor of either would be to do these
> two commands?
>
>         git checkout --ours $path_the_user_wants_to_use
>         git rm --cached $the_other_path
>
> If the path the user wants to use matches what the branch being
> merged has, then replace "--ours" above with "--theirs".
>
> Would that be a good explanation?

Oh, good point; we may need additional documentation to address this,
though it would be nice if we could minimize it.  As far as the
particular solution, I think we should avoid checkout --ours, for a
few reasons:
  * 'checkout --ours' only reads from and does not update the index,
so it wouldn't resolve the conflict.
  * I think expecting users to figure out --ours vs. --theirs is
confusing, given that users perceive them as reversed in rebase vs
merge, and cherry-pick is somewhere inbetween.
  * In the case of a transitively renamed path (like
list_of_favorites.txt above), --ours might ignore content changes from
one side.

I would prefer to tell the user they can resolve the conflict with two
other commands.  I'm currently thinking of something like these two:
    git add $directory_renamed_path
    git mv $directory_renamed_path $original_path [&& git add $original_path ?]
This pair assumes we write the working tree and index entries for
$directory_renamed_path and leave $original_path empty in both the
working tree and index.  We could alternatively reverse that, with an
equivalent but swapped set of commands for resolution. We can't use
this exact set of commands today, as users would have to do a 'git
add' before a 'git mv'.  I think 'git mv' should be modified to allow
working with higher stage entries (possibly always preserving them?),
which has come up before[1].

[1] https://public-inbox.org/git/xmqqbmabcuhf.fsf@gitster-ct.c.googlers.com/

> Regarding the implementation (not the use of stages, but how
> "mark_conflicted" variable gets used), I am not sure if I agree that
> only choice (c) should give the hint.  Regardless of the settings,
> we know both paths this file may want to end up with, and I suspect
> that the alternative a/b/c you gave are how by default the tool
> automatically places the result, giving a chance to the end user to
> correct mistakes.  I wonder if it is possible to somehow show "the
> other possibilty" in the merge log even when choice (a) or (b) are
> in effect?  E.g. "path X/B moved to Y/B because the other side moved
> X/A to Y/A" when choice (b) is in use, and "path X/B kept there but
> the other side moved neighbouring A/X to Y/A" when choice (a) is in
> use.

I think it makes sense when (b) is in effect but I'm not sure about
(a).  To print such messages, we first have to try to detect renames
(which we currently don't do with (a) though we could change that),
and for the messages to be useful we should believe they are better
than a coin flip's chance of being right.  We use choice (a) with
git-am right now because the fake-ancestor-tree thing means we believe
any directory rename detection is likely to be wrong.

> Another thing that makes me wonder is if this should be treated
> similar to rerere.autoupdate; even when rerere kicks in to resolve
> otherwise conflicting tricky merge, without being explicitly allowed
> with the config, it does not register the resolution to the index at
> stage #0.  Either choices (a) that ignores neighbouring files'
> movement or (b) that follows the movement lets this tricky
> heuristics not just suggest the end result, but allows it to
> register the result at stage #0, which somehow feels too aggressive
> (which was what triggered my suggestion to go with (c)).  With that
> attitude, we may be able to get rid of choice (a) altogether, which
> may make things a tad simpler.  IOW, we assume the heuristics would
> suggest the right solution most of the time, just like we assume
> rerere gives a reasonable resolution most of the time, with a knob
> to accept the result blindly, together with hints to recover when
> heuristics makes mistakes.

I like that analogy.  I think that aligns well with my possible
conflict-resolution commands, and further answers the question about
whether to put the new path or the old path in the working tree and
index.

However, we do need some form of choice (a) for commands which can't
provide accurate tree information, such as git-am.

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Junio C Hamano]

Elijah Newren <newren@gmail.com> writes:

> I'm not sure I'm following well enough to answer any your question(s),
> so I'll instead ask a few of my own:
>   * Are you referring to stage #2 and stage #3 of the old path or the
> new path or one of each or both of each?

If they moved the sole neighbouring file X/A to Y/A, while we added
a new path to X/B, I would expect we'd have two blobs with the same
content we added, one at X/B at stage #2 (because that is what we
wanted to have) and the other at Y/B at stage #3 (that's their wish
the heuristic is guessing).  If it were the other way, the stages
would be different.

>   * Would this be consistent with how normal renames behave?
> and, as a partial answer to your question:

The use of the three-way merge logic at the tree structure level,
unlike the "because neighbours moved" heuristics, gives a more
definite answer.  We see that the contents in the original at path A
(in the common ancestor version) is now at path B (with or without
slight modification) in their tree, while we kept it at path A
(again, with or without modification).  Or vice versa.  Either way,
at the tree structure level, that is "one side changes, while the
other side does not modify" which is resolved cleanly to "take the
new path the side that modifies wants the file to have".  So we do
not need to use the stages to represent "these sides wants to place
it at different paths, which one is correct?"  Instead, we'd have
stages #1 (common ancestor), #2 (ours) and #3 (theirs) all at path B
(i.e. the cleanly resolved structural change conflict) to help the
user reconcile content level conflicts (iff needed).


> I would prefer to tell the user they can resolve the conflict with two
> other commands.  I'm currently thinking of something like these two:
>     git add $directory_renamed_path
>     git mv $directory_renamed_path $original_path [&& git add $original_path ?]
> This pair assumes we write the working tree and index entries for
> $directory_renamed_path and leave $original_path empty in both the
> working tree and index.  We could alternatively reverse that, with an
> equivalent but swapped set of commands for resolution.

Yeah, the final version may have difference in detail, but I think
it is sensible to leave a state, from which the user can go in
either direction, with a simple command or two, like the above one.

>> ...  With that
>> attitude, we may be able to get rid of choice (a) altogether, which
>> may make things a tad simpler.  IOW, we assume the heuristics would
>> suggest the right solution most of the time, just like we assume
>> rerere gives a reasonable resolution most of the time, with a knob
>> to accept the result blindly, together with hints to recover when
>> heuristics makes mistakes.
>
> I like that analogy.  I think that aligns well with my possible
> conflict-resolution commands, and further answers the question about
> whether to put the new path or the old path in the working tree and
> index.
>
> However, we do need some form of choice (a) for commands which can't
> provide accurate tree information, such as git-am.

Yeah, if we are not even running the heuristics for that case (a),
hence it is not sensible to expect to offer "if we were doing
directory renames, this path might have gone to that other place",
then I think I am fine with not giving any hint to change their mind
(after all, they can "git reset --hard" and retry the merge, this
time not using the non-default (a) mode).  And keeping around the
simplest "we do not even attempt to" (a) mode as another option is
fine by me.

THanks.

Re: [BUG] All files in folder are moved when cherry-picking commit that moves fewer files

[Junio C Hamano]

Elijah Newren <newren@gmail.com> writes:

> I'm not sure I'm following well enough to answer any your question(s),
> so I'll instead ask a few of my own:
>   * Are you referring to stage #2 and stage #3 of the old path or the
> new path or one of each or both of each?

If they moved the sole neighbouring file X/A to Y/A, while we added
a new path to X/B, I would expect we'd have two blobs with the same
content we added, one at X/B at stage #2 (because that is what we
wanted to have) and the other at Y/B at stage #3 (that's their wish
the heuristic is guessing).  If it were the other way, the stages
would be different.

>   * Would this be consistent with how normal renames behave?
> and, as a partial answer to your question:

The use of the three-way merge logic at the tree structure level,
unlike the "because neighbours moved" heuristics, gives a more
definite answer.  We see that the contents in the original at path A
(in the common ancestor version) is now at path B (with or without
slight modification) in their tree, while we kept it at path A
(again, with or without modification).  Or vice versa.  Either way,
at the tree structure level, that is "one side changes, while the
other side does not modify" which is resolved cleanly to "take the
new path the side that modifies wants the file to have".  So we do
not need to use the stages to represent "these sides wants to place
it at different paths, which one is correct?"  Instead, we'd have
stages #1 (common ancestor), #2 (ours) and #3 (theirs) all at path B
(i.e. the cleanly resolved structural change conflict) to help the
user reconcile content level conflicts (iff needed).


> I would prefer to tell the user they can resolve the conflict with two
> other commands.  I'm currently thinking of something like these two:
>     git add $directory_renamed_path
>     git mv $directory_renamed_path $original_path [&& git add $original_path ?]
> This pair assumes we write the working tree and index entries for
> $directory_renamed_path and leave $original_path empty in both the
> working tree and index.  We could alternatively reverse that, with an
> equivalent but swapped set of commands for resolution.

Yeah, the final version may have difference in detail, but I think
it is sensible to leave a state, from which the user can go in
either direction, with a simple command or two, like the above one.

>> ...  With that
>> attitude, we may be able to get rid of choice (a) altogether, which
>> may make things a tad simpler.  IOW, we assume the heuristics would
>> suggest the right solution most of the time, just like we assume
>> rerere gives a reasonable resolution most of the time, with a knob
>> to accept the result blindly, together with hints to recover when
>> heuristics makes mistakes.
>
> I like that analogy.  I think that aligns well with my possible
> conflict-resolution commands, and further answers the question about
> whether to put the new path or the old path in the working tree and
> index.
>
> However, we do need some form of choice (a) for commands which can't
> provide accurate tree information, such as git-am.

Yeah, if we are not even running the heuristics for that case (a),
hence it is not sensible to expect to offer "if we were doing
directory renames, this path might have gone to that other place",
then I think I am fine with not giving any hint to change their mind
(after all, they can "git reset --hard" and retry the merge, this
time not using the non-default (a) mode).  And keeping around the
simplest "we do not even attempt to" (a) mode as another option is
fine by me.

Thanks.

[PATCH v2 00/15] Switch directory rename detection default

[Elijah Newren]

I know this is kinda big, but it's mostly simple mechanical cleanups.
Stuff I'd like reviewers to focus on:
  * Patch 15, particularly looking over the new testcases (13a-13d) in
    t6043 and the documentation.
  * Should I have switched 'unsigned short' to 'unsigned' instead of
    vice-versa in patch 1?
  * Similarly, does anyone have a reason to prefer oid,mode pair over
    using a diff_filespec as I did in patch 11?

The crux of this series is in patch 15, changing the default for
directory rename detection to treat it as a conflict.  It is similar
to the patch Junio previously reviewed; changes:

  * It now also handles files renamed into directories on one side
    where the other side renamed the directory away.  (Previously, it
    only handled new files added into such directories.)
    
  * As suggested by Junio, even if merge.directoryRenames=true is set
    in config (to accept directory rename heuristics as correct
    without reporting conflicts), messages will now be printed about
    the paths being changed by directory renames.
    
  * Error and info messages updated based in part on Junio's
    suggestions, a second check that the messages make sense would be
    useful.
  
  * There are now testcases testing the conflict and information
    message output (testcases 13[abcd] in t6043)


The reason this series exploded from one patch to fifteen was the need
to handle transitive renames (renames into directories on one side
while the other side renamed that directory away).  For that, I needed
to plumb more information through...but quickly got frustrated with
various ugly code bits and went down a rabbit hole.

The first 12 patches are solely cleanups

Patches 13 & 14 are simple changes to make additional information
available.

Patch 15 is primary purpose of the series, described above.


Elijah Newren (15):
  Use 'unsigned short' for mode, like diff_filespec does
  merge-recursive: rename merge_options argument from 'o' to 'opt'
  merge-recursive: rename diff_filespec 'one' to 'o'
  merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
  merge-recursive: use 'ci' for rename_conflict_info variable name
  merge-recursive: move some struct declarations together
  merge-recursive: shrink rename_conflict_info
  merge-recursive: remove ren[12]_other fields from rename_conflict_info
  merge-recursive: track branch where rename occurred in rename struct
  merge-recursive: cleanup handle_rename_* function signatures
  merge-recursive: switch from (oid,mode) pairs to a diff_filespec
  t6043: fix copied test description to match its purpose
  merge-recursive: track information associated with directory renames
  merge-recursive: give callers of handle_content_merge() access to
    contents
  merge-recursive: switch directory rename detection default

 Documentation/config/merge.txt         |   19 +-
 archive.c                              |    2 +-
 blame.c                                |    2 +-
 blame.h                                |    2 +-
 builtin/rm.c                           |    2 +-
 builtin/update-index.c                 |    2 +-
 cache.h                                |    2 +-
 fsck.c                                 |    2 +-
 line-log.c                             |    2 +-
 match-trees.c                          |    8 +-
 merge-recursive.c                      | 1853 ++++++++++++------------
 notes.c                                |    2 +-
 sha1-name.c                            |    2 +-
 t/t3401-rebase-and-am-rename.sh        |    8 +-
 t/t6043-merge-rename-directories.sh    |  462 +++++-
 t/t6046-merge-skip-unneeded-updates.sh |    8 +-
 tree-diff.c                            |    2 +-
 tree-walk.c                            |    6 +-
 tree-walk.h                            |    6 +-
 19 files changed, 1367 insertions(+), 1025 deletions(-)

-- 
2.21.0.211.gb523892db9

[PATCH v2 01/15] Use 'unsigned short' for mode, like diff_filespec does

[Elijah Newren]

struct diff_filespec defines mode to be an 'unsigned short'.  Several
other places in the API which we'd like to interact with using a
diff_filespec used a plain unsigned (or unsigned int).  This caused
problems when taking addresses, so switch to unsigned short.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 archive.c              | 2 +-
 blame.c                | 2 +-
 blame.h                | 2 +-
 builtin/rm.c           | 2 +-
 builtin/update-index.c | 2 +-
 cache.h                | 2 +-
 fsck.c                 | 2 +-
 line-log.c             | 2 +-
 match-trees.c          | 8 ++++----
 merge-recursive.c      | 6 +++---
 notes.c                | 2 +-
 sha1-name.c            | 2 +-
 tree-diff.c            | 2 +-
 tree-walk.c            | 6 +++---
 tree-walk.h            | 6 +++---
 15 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/archive.c b/archive.c
index 1f98324a93..92bc001545 100644
--- a/archive.c
+++ b/archive.c
@@ -415,7 +415,7 @@ static void parse_treeish_arg(const char **argv,
 
 	if (prefix) {
 		struct object_id tree_oid;
-		unsigned int mode;
+		unsigned short mode;
 		int err;
 
 		err = get_tree_entry(&tree->object.oid, prefix, &tree_oid,
diff --git a/blame.c b/blame.c
index 5c07dec190..326231476e 100644
--- a/blame.c
+++ b/blame.c
@@ -99,7 +99,7 @@ static void verify_working_tree_path(struct repository *r,
 	for (parents = work_tree->parents; parents; parents = parents->next) {
 		const struct object_id *commit_oid = &parents->item->object.oid;
 		struct object_id blob_oid;
-		unsigned mode;
+		unsigned short mode;
 
 		if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
 		    oid_object_info(r, &blob_oid, NULL) == OBJ_BLOB)
diff --git a/blame.h b/blame.h
index be3a895043..2a285eb027 100644
--- a/blame.h
+++ b/blame.h
@@ -52,7 +52,7 @@ struct blame_origin {
 	struct blame_entry *suspects;
 	mmfile_t file;
 	struct object_id blob_oid;
-	unsigned mode;
+	unsigned short mode;
 	/* guilty gets set when shipping any suspects to the final
 	 * blame list instead of other commits
 	 */
diff --git a/builtin/rm.c b/builtin/rm.c
index db85b33982..90cbe896c9 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -110,7 +110,7 @@ static int check_local_mod(struct object_id *head, int index_only)
 		const struct cache_entry *ce;
 		const char *name = list.entry[i].name;
 		struct object_id oid;
-		unsigned mode;
+		unsigned short mode;
 		int local_changes = 0;
 		int staged_changes = 0;
 
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 1b6c42f748..0baf51c316 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -597,7 +597,7 @@ static struct cache_entry *read_one_ent(const char *which,
 					struct object_id *ent, const char *path,
 					int namelen, int stage)
 {
-	unsigned mode;
+	unsigned short mode;
 	struct object_id oid;
 	struct cache_entry *ce;
 
diff --git a/cache.h b/cache.h
index ac92421f3a..851c3e6945 100644
--- a/cache.h
+++ b/cache.h
@@ -1331,7 +1331,7 @@ static inline int hex2chr(const char *s)
 #define FALLBACK_DEFAULT_ABBREV 7
 
 struct object_context {
-	unsigned mode;
+	unsigned short mode;
 	/*
 	 * symlink_path is only used by get_tree_entry_follow_symlinks,
 	 * and only for symlinks that point outside the repository.
diff --git a/fsck.c b/fsck.c
index 2260adb71e..4703f55561 100644
--- a/fsck.c
+++ b/fsck.c
@@ -604,7 +604,7 @@ static int fsck_tree(struct tree *item, struct fsck_options *options)
 	o_name = NULL;
 
 	while (desc.size) {
-		unsigned mode;
+		unsigned short mode;
 		const char *name;
 		const struct object_id *oid;
 
diff --git a/line-log.c b/line-log.c
index 24e21731c4..f743592bc0 100644
--- a/line-log.c
+++ b/line-log.c
@@ -498,7 +498,7 @@ static struct commit *check_single_commit(struct rev_info *revs)
 
 static void fill_blob_sha1(struct commit *commit, struct diff_filespec *spec)
 {
-	unsigned mode;
+	unsigned short mode;
 	struct object_id oid;
 
 	if (get_tree_entry(&commit->object.oid, spec->path, &oid, &mode))
diff --git a/match-trees.c b/match-trees.c
index ddc4d39845..9d1ec8d6b0 100644
--- a/match-trees.c
+++ b/match-trees.c
@@ -140,7 +140,7 @@ static void match_trees(const struct object_id *hash1,
 	while (one.size) {
 		const char *path;
 		const struct object_id *elem;
-		unsigned mode;
+		unsigned short mode;
 		int score;
 
 		elem = tree_entry_extract(&one, &path, &mode);
@@ -196,7 +196,7 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
 	rewrite_here = NULL;
 	while (desc.size) {
 		const char *name;
-		unsigned mode;
+		unsigned short mode;
 
 		tree_entry_extract(&desc, &name, &mode);
 		if (strlen(name) == toplen &&
@@ -285,7 +285,7 @@ void shift_tree(const struct object_id *hash1,
 
 	if (add_score < del_score) {
 		/* We need to pick a subtree of two */
-		unsigned mode;
+		unsigned short mode;
 
 		if (!*del_prefix)
 			return;
@@ -313,7 +313,7 @@ void shift_tree_by(const struct object_id *hash1,
 		   const char *shift_prefix)
 {
 	struct object_id sub1, sub2;
-	unsigned mode1, mode2;
+	unsigned short mode1, mode2;
 	unsigned candidate = 0;
 
 	/* Can hash2 be a tree at shift_prefix in tree hash1? */
diff --git a/merge-recursive.c b/merge-recursive.c
index 6c40c61c47..fcf37be2a7 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -214,7 +214,7 @@ struct rename_conflict_info {
  */
 struct stage_data {
 	struct {
-		unsigned mode;
+		unsigned short mode;
 		struct object_id oid;
 	} stages[4];
 	struct rename_conflict_info *rename_conflict_info;
@@ -482,7 +482,7 @@ static void get_files_dirs(struct merge_options *o, struct tree *tree)
 static int get_tree_entry_if_blob(const struct object_id *tree,
 				  const char *path,
 				  struct object_id *hashy,
-				  unsigned int *mode_o)
+				  unsigned short *mode_o)
 {
 	int ret;
 
@@ -1935,7 +1935,7 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 static int tree_has_path(struct tree *tree, const char *path)
 {
 	struct object_id hashy;
-	unsigned int mode_o;
+	unsigned short mode_o;
 
 	return !get_tree_entry(&tree->object.oid, path,
 			       &hashy, &mode_o);
diff --git a/notes.c b/notes.c
index 7f7cc4d511..ba4cae7851 100644
--- a/notes.c
+++ b/notes.c
@@ -986,7 +986,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 		combine_notes_fn combine_notes, int flags)
 {
 	struct object_id oid, object_oid;
-	unsigned mode;
+	unsigned short mode;
 	struct leaf_node root_tree;
 
 	if (!t)
diff --git a/sha1-name.c b/sha1-name.c
index 6dda2c16df..d4b3d01f3c 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -1577,7 +1577,7 @@ static void diagnose_invalid_oid_path(const char *prefix,
 				      int object_name_len)
 {
 	struct object_id oid;
-	unsigned mode;
+	unsigned short mode;
 
 	if (!prefix)
 		prefix = "";
diff --git a/tree-diff.c b/tree-diff.c
index e6d306f69f..f1f641eb6a 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -181,7 +181,7 @@ static struct combine_diff_path *emit_path(struct combine_diff_path *p,
 	struct tree_desc *t, struct tree_desc *tp,
 	int imin)
 {
-	unsigned mode;
+	unsigned short mode;
 	const char *path;
 	const struct object_id *oid;
 	int pathlen;
diff --git a/tree-walk.c b/tree-walk.c
index 1e4bbc8a0e..ec32a47b2e 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -500,7 +500,7 @@ struct dir_state {
 	struct object_id oid;
 };
 
-static int find_tree_entry(struct tree_desc *t, const char *name, struct object_id *result, unsigned *mode)
+static int find_tree_entry(struct tree_desc *t, const char *name, struct object_id *result, unsigned short *mode)
 {
 	int namelen = strlen(name);
 	while (t->size) {
@@ -535,7 +535,7 @@ static int find_tree_entry(struct tree_desc *t, const char *name, struct object_
 	return -1;
 }
 
-int get_tree_entry(const struct object_id *tree_oid, const char *name, struct object_id *oid, unsigned *mode)
+int get_tree_entry(const struct object_id *tree_oid, const char *name, struct object_id *oid, unsigned short *mode)
 {
 	int retval;
 	void *tree;
@@ -585,7 +585,7 @@ int get_tree_entry(const struct object_id *tree_oid, const char *name, struct ob
  * See the code for enum get_oid_result for a description of
  * the return values.
  */
-enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode)
+enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned short *mode)
 {
 	int retval = MISSING_OBJECT;
 	struct dir_state *parents = NULL;
diff --git a/tree-walk.h b/tree-walk.h
index 8225171866..3aa381b6a3 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -16,7 +16,7 @@ struct tree_desc {
 	unsigned int size;
 };
 
-static inline const struct object_id *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
+static inline const struct object_id *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned short *modep)
 {
 	*pathp = desc->entry.path;
 	*modep = desc->entry.mode;
@@ -51,7 +51,7 @@ struct traverse_info;
 typedef int (*traverse_callback_t)(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *);
 int traverse_trees(struct index_state *istate, int n, struct tree_desc *t, struct traverse_info *info);
 
-enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode);
+enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned short *mode);
 
 struct traverse_info {
 	const char *traverse_path;
@@ -66,7 +66,7 @@ struct traverse_info {
 	int show_all_errors;
 };
 
-int get_tree_entry(const struct object_id *, const char *, struct object_id *, unsigned *);
+int get_tree_entry(const struct object_id *, const char *, struct object_id *, unsigned short *);
 extern char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n);
 extern void setup_traverse_info(struct traverse_info *info, const char *base);
 
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 02/15] merge-recursive: rename merge_options argument from 'o' to 'opt'

[Elijah Newren]

The name 'o' was used for the merge_options struct pointer taken by many
functions, but in a few places it was named 'opt'.  Several functions
that didn't need merge_options instead used 'o' for a diff_filespec
argument or local.  Some functions needed both an inconsistently either
renamed the merge_options to 'opt' or the diff_filespec to 'one'.  I
want to remove the weird split in the codebase between using a
diff_filespec and a pair of (oid,mode) values in favor of using a
diff_filespec everywhere, but that dramatically increases the number of
cases where we want to use 'o' as a diff_filespec.  Rename the
merge_options argument to 'opt' to make room.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 984 +++++++++++++++++++++++-----------------------
 1 file changed, 492 insertions(+), 492 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index fcf37be2a7..09b76d596e 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -115,32 +115,32 @@ static void collision_init(struct hashmap *map)
 	hashmap_init(map, (hashmap_cmp_fn) collision_cmp, NULL, 0);
 }
 
-static void flush_output(struct merge_options *o)
+static void flush_output(struct merge_options *opt)
 {
-	if (o->buffer_output < 2 && o->obuf.len) {
-		fputs(o->obuf.buf, stdout);
-		strbuf_reset(&o->obuf);
+	if (opt->buffer_output < 2 && opt->obuf.len) {
+		fputs(opt->obuf.buf, stdout);
+		strbuf_reset(&opt->obuf);
 	}
 }
 
-static int err(struct merge_options *o, const char *err, ...)
+static int err(struct merge_options *opt, const char *err, ...)
 {
 	va_list params;
 
-	if (o->buffer_output < 2)
-		flush_output(o);
+	if (opt->buffer_output < 2)
+		flush_output(opt);
 	else {
-		strbuf_complete(&o->obuf, '\n');
-		strbuf_addstr(&o->obuf, "error: ");
+		strbuf_complete(&opt->obuf, '\n');
+		strbuf_addstr(&opt->obuf, "error: ");
 	}
 	va_start(params, err);
-	strbuf_vaddf(&o->obuf, err, params);
+	strbuf_vaddf(&opt->obuf, err, params);
 	va_end(params);
-	if (o->buffer_output > 1)
-		strbuf_addch(&o->obuf, '\n');
+	if (opt->buffer_output > 1)
+		strbuf_addch(&opt->obuf, '\n');
 	else {
-		error("%s", o->obuf.buf);
-		strbuf_reset(&o->obuf);
+		error("%s", opt->obuf.buf);
+		strbuf_reset(&opt->obuf);
 	}
 
 	return -1;
@@ -228,7 +228,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      const char *branch2,
 					      struct stage_data *dst_entry1,
 					      struct stage_data *dst_entry2,
-					      struct merge_options *o,
+					      struct merge_options *opt,
 					      struct stage_data *src_entry1,
 					      struct stage_data *src_entry2)
 {
@@ -239,15 +239,15 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 * When we have two renames involved, it's easiest to get the
 	 * correct things into stage 2 and 3, and to make sure that the
 	 * content merge puts HEAD before the other branch if we just
-	 * ensure that branch1 == o->branch1.  So, simply flip arguments
+	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (dst_entry2 && branch1 != o->branch1) {
+	if (dst_entry2 && branch1 != opt->branch1) {
 		setup_rename_conflict_info(rename_type,
 					   pair2,      pair1,
 					   branch2,    branch1,
 					   dst_entry2, dst_entry1,
-					   o,
+					   opt,
 					   src_entry2, src_entry1);
 		return;
 	}
@@ -276,7 +276,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 */
 	if (rename_type == RENAME_ADD ||
 	    rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage1 = o->branch1 == branch1 ? 3 : 2;
+		ostage1 = opt->branch1 == branch1 ? 3 : 2;
 
 		ci->ren1_other.path = pair1->one->path;
 		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
@@ -292,67 +292,67 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	}
 }
 
-static int show(struct merge_options *o, int v)
+static int show(struct merge_options *opt, int v)
 {
-	return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
+	return (!opt->call_depth && opt->verbosity >= v) || opt->verbosity >= 5;
 }
 
 __attribute__((format (printf, 3, 4)))
-static void output(struct merge_options *o, int v, const char *fmt, ...)
+static void output(struct merge_options *opt, int v, const char *fmt, ...)
 {
 	va_list ap;
 
-	if (!show(o, v))
+	if (!show(opt, v))
 		return;
 
-	strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
+	strbuf_addchars(&opt->obuf, ' ', opt->call_depth * 2);
 
 	va_start(ap, fmt);
-	strbuf_vaddf(&o->obuf, fmt, ap);
+	strbuf_vaddf(&opt->obuf, fmt, ap);
 	va_end(ap);
 
-	strbuf_addch(&o->obuf, '\n');
-	if (!o->buffer_output)
-		flush_output(o);
+	strbuf_addch(&opt->obuf, '\n');
+	if (!opt->buffer_output)
+		flush_output(opt);
 }
 
-static void output_commit_title(struct merge_options *o, struct commit *commit)
+static void output_commit_title(struct merge_options *opt, struct commit *commit)
 {
 	struct merge_remote_desc *desc;
 
-	strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
+	strbuf_addchars(&opt->obuf, ' ', opt->call_depth * 2);
 	desc = merge_remote_util(commit);
 	if (desc)
-		strbuf_addf(&o->obuf, "virtual %s\n", desc->name);
+		strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
 	else {
-		strbuf_add_unique_abbrev(&o->obuf, &commit->object.oid,
+		strbuf_add_unique_abbrev(&opt->obuf, &commit->object.oid,
 					 DEFAULT_ABBREV);
-		strbuf_addch(&o->obuf, ' ');
+		strbuf_addch(&opt->obuf, ' ');
 		if (parse_commit(commit) != 0)
-			strbuf_addstr(&o->obuf, _("(bad commit)\n"));
+			strbuf_addstr(&opt->obuf, _("(bad commit)\n"));
 		else {
 			const char *title;
 			const char *msg = get_commit_buffer(commit, NULL);
 			int len = find_commit_subject(msg, &title);
 			if (len)
-				strbuf_addf(&o->obuf, "%.*s\n", len, title);
+				strbuf_addf(&opt->obuf, "%.*s\n", len, title);
 			unuse_commit_buffer(commit, msg);
 		}
 	}
-	flush_output(o);
+	flush_output(opt);
 }
 
-static int add_cacheinfo(struct merge_options *o,
+static int add_cacheinfo(struct merge_options *opt,
 			 unsigned int mode, const struct object_id *oid,
 			 const char *path, int stage, int refresh, int options)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 	struct cache_entry *ce;
 	int ret;
 
 	ce = make_cache_entry(istate, mode, oid ? oid : &null_oid, path, stage, 0);
 	if (!ce)
-		return err(o, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
+		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
 	ret = add_index_entry(istate, ce, options);
 	if (refresh) {
@@ -361,7 +361,7 @@ static int add_cacheinfo(struct merge_options *o,
 		nce = refresh_cache_entry(istate, ce,
 					  CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 		if (!nce)
-			return err(o, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
+			return err(opt, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
 		if (nce != ce)
 			ret = add_index_entry(istate, nce, options);
 	}
@@ -374,7 +374,7 @@ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 	init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int unpack_trees_start(struct merge_options *o,
+static int unpack_trees_start(struct merge_options *opt,
 			      struct tree *common,
 			      struct tree *head,
 			      struct tree *merge)
@@ -383,49 +383,49 @@ static int unpack_trees_start(struct merge_options *o,
 	struct tree_desc t[3];
 	struct index_state tmp_index = { NULL };
 
-	memset(&o->unpack_opts, 0, sizeof(o->unpack_opts));
-	if (o->call_depth)
-		o->unpack_opts.index_only = 1;
+	memset(&opt->unpack_opts, 0, sizeof(opt->unpack_opts));
+	if (opt->call_depth)
+		opt->unpack_opts.index_only = 1;
 	else
-		o->unpack_opts.update = 1;
-	o->unpack_opts.merge = 1;
-	o->unpack_opts.head_idx = 2;
-	o->unpack_opts.fn = threeway_merge;
-	o->unpack_opts.src_index = o->repo->index;
-	o->unpack_opts.dst_index = &tmp_index;
-	o->unpack_opts.aggressive = !merge_detect_rename(o);
-	setup_unpack_trees_porcelain(&o->unpack_opts, "merge");
+		opt->unpack_opts.update = 1;
+	opt->unpack_opts.merge = 1;
+	opt->unpack_opts.head_idx = 2;
+	opt->unpack_opts.fn = threeway_merge;
+	opt->unpack_opts.src_index = opt->repo->index;
+	opt->unpack_opts.dst_index = &tmp_index;
+	opt->unpack_opts.aggressive = !merge_detect_rename(opt);
+	setup_unpack_trees_porcelain(&opt->unpack_opts, "merge");
 
 	init_tree_desc_from_tree(t+0, common);
 	init_tree_desc_from_tree(t+1, head);
 	init_tree_desc_from_tree(t+2, merge);
 
-	rc = unpack_trees(3, t, &o->unpack_opts);
-	cache_tree_free(&o->repo->index->cache_tree);
+	rc = unpack_trees(3, t, &opt->unpack_opts);
+	cache_tree_free(&opt->repo->index->cache_tree);
 
 	/*
-	 * Update o->repo->index to match the new results, AFTER saving a copy
-	 * in o->orig_index.  Update src_index to point to the saved copy.
+	 * Update opt->repo->index to match the new results, AFTER saving a copy
+	 * in opt->orig_index.  Update src_index to point to the saved copy.
 	 * (verify_uptodate() checks src_index, and the original index is
 	 * the one that had the necessary modification timestamps.)
 	 */
-	o->orig_index = *o->repo->index;
-	*o->repo->index = tmp_index;
-	o->unpack_opts.src_index = &o->orig_index;
+	opt->orig_index = *opt->repo->index;
+	*opt->repo->index = tmp_index;
+	opt->unpack_opts.src_index = &opt->orig_index;
 
 	return rc;
 }
 
-static void unpack_trees_finish(struct merge_options *o)
+static void unpack_trees_finish(struct merge_options *opt)
 {
-	discard_index(&o->orig_index);
-	clear_unpack_trees_porcelain(&o->unpack_opts);
+	discard_index(&opt->orig_index);
+	clear_unpack_trees_porcelain(&opt->unpack_opts);
 }
 
-struct tree *write_tree_from_memory(struct merge_options *o)
+struct tree *write_tree_from_memory(struct merge_options *opt)
 {
 	struct tree *result = NULL;
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 
 	if (unmerged_index(istate)) {
 		int i;
@@ -444,11 +444,11 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 
 	if (!cache_tree_fully_valid(istate->cache_tree) &&
 	    cache_tree_update(istate, 0) < 0) {
-		err(o, _("error building trees"));
+		err(opt, _("error building trees"));
 		return NULL;
 	}
 
-	result = lookup_tree(o->repo, &istate->cache_tree->oid);
+	result = lookup_tree(opt->repo, &istate->cache_tree->oid);
 
 	return result;
 }
@@ -459,24 +459,24 @@ static int save_files_dirs(const struct object_id *oid,
 {
 	struct path_hashmap_entry *entry;
 	int baselen = base->len;
-	struct merge_options *o = context;
+	struct merge_options *opt = context;
 
 	strbuf_addstr(base, path);
 
 	FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
 	hashmap_entry_init(entry, path_hash(entry->path));
-	hashmap_add(&o->current_file_dir_set, entry);
+	hashmap_add(&opt->current_file_dir_set, entry);
 
 	strbuf_setlen(base, baselen);
 	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 }
 
-static void get_files_dirs(struct merge_options *o, struct tree *tree)
+static void get_files_dirs(struct merge_options *opt, struct tree *tree)
 {
 	struct pathspec match_all;
 	memset(&match_all, 0, sizeof(match_all));
 	read_tree_recursive(the_repository, tree, "", 0, 0,
-			    &match_all, save_files_dirs, o);
+			    &match_all, save_files_dirs, opt);
 }
 
 static int get_tree_entry_if_blob(const struct object_id *tree,
@@ -573,7 +573,7 @@ static int string_list_df_name_compare(const char *one, const char *two)
 	return onelen - twolen;
 }
 
-static void record_df_conflict_files(struct merge_options *o,
+static void record_df_conflict_files(struct merge_options *opt,
 				     struct string_list *entries)
 {
 	/* If there is a D/F conflict and the file for such a conflict
@@ -598,7 +598,7 @@ static void record_df_conflict_files(struct merge_options *o,
 	 * If we're merging merge-bases, we don't want to bother with
 	 * any working directory changes.
 	 */
-	if (o->call_depth)
+	if (opt->call_depth)
 		return;
 
 	/* Ensure D/F conflicts are adjacent in the entries list. */
@@ -610,7 +610,7 @@ static void record_df_conflict_files(struct merge_options *o,
 	df_sorted_entries.cmp = string_list_df_name_compare;
 	string_list_sort(&df_sorted_entries);
 
-	string_list_clear(&o->df_conflict_file_set, 1);
+	string_list_clear(&opt->df_conflict_file_set, 1);
 	for (i = 0; i < df_sorted_entries.nr; i++) {
 		const char *path = df_sorted_entries.items[i].string;
 		int len = strlen(path);
@@ -626,7 +626,7 @@ static void record_df_conflict_files(struct merge_options *o,
 		    len > last_len &&
 		    memcmp(path, last_file, last_len) == 0 &&
 		    path[last_len] == '/') {
-			string_list_insert(&o->df_conflict_file_set, last_file);
+			string_list_insert(&opt->df_conflict_file_set, last_file);
 		}
 
 		/*
@@ -717,20 +717,20 @@ static void update_entry(struct stage_data *entry,
 	oidcpy(&entry->stages[3].oid, &b->oid);
 }
 
-static int remove_file(struct merge_options *o, int clean,
+static int remove_file(struct merge_options *opt, int clean,
 		       const char *path, int no_wd)
 {
-	int update_cache = o->call_depth || clean;
-	int update_working_directory = !o->call_depth && !no_wd;
+	int update_cache = opt->call_depth || clean;
+	int update_working_directory = !opt->call_depth && !no_wd;
 
 	if (update_cache) {
-		if (remove_file_from_index(o->repo->index, path))
+		if (remove_file_from_index(opt->repo->index, path))
 			return -1;
 	}
 	if (update_working_directory) {
 		if (ignore_case) {
 			struct cache_entry *ce;
-			ce = index_file_exists(o->repo->index, path, strlen(path),
+			ce = index_file_exists(opt->repo->index, path, strlen(path),
 					       ignore_case);
 			if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
 				return 0;
@@ -751,7 +751,7 @@ static void add_flattened_path(struct strbuf *out, const char *s)
 			out->buf[i] = '_';
 }
 
-static char *unique_path(struct merge_options *o, const char *path, const char *branch)
+static char *unique_path(struct merge_options *opt, const char *path, const char *branch)
 {
 	struct path_hashmap_entry *entry;
 	struct strbuf newpath = STRBUF_INIT;
@@ -762,16 +762,16 @@ static char *unique_path(struct merge_options *o, const char *path, const char *
 	add_flattened_path(&newpath, branch);
 
 	base_len = newpath.len;
-	while (hashmap_get_from_hash(&o->current_file_dir_set,
+	while (hashmap_get_from_hash(&opt->current_file_dir_set,
 				     path_hash(newpath.buf), newpath.buf) ||
-	       (!o->call_depth && file_exists(newpath.buf))) {
+	       (!opt->call_depth && file_exists(newpath.buf))) {
 		strbuf_setlen(&newpath, base_len);
 		strbuf_addf(&newpath, "_%d", suffix++);
 	}
 
 	FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
 	hashmap_entry_init(entry, path_hash(entry->path));
-	hashmap_add(&o->current_file_dir_set, entry);
+	hashmap_add(&opt->current_file_dir_set, entry);
 	return strbuf_detach(&newpath, NULL);
 }
 
@@ -810,10 +810,10 @@ static int dir_in_way(struct index_state *istate, const char *path,
  * Returns whether path was tracked in the index before the merge started,
  * and its oid and mode match the specified values
  */
-static int was_tracked_and_matches(struct merge_options *o, const char *path,
+static int was_tracked_and_matches(struct merge_options *opt, const char *path,
 				   const struct object_id *oid, unsigned mode)
 {
-	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 	struct cache_entry *ce;
 
 	if (0 > pos)
@@ -821,16 +821,16 @@ static int was_tracked_and_matches(struct merge_options *o, const char *path,
 		return 0;
 
 	/* See if the file we were tracking before matches */
-	ce = o->orig_index.cache[pos];
+	ce = opt->orig_index.cache[pos];
 	return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
 }
 
 /*
  * Returns whether path was tracked in the index before the merge started
  */
-static int was_tracked(struct merge_options *o, const char *path)
+static int was_tracked(struct merge_options *opt, const char *path)
 {
-	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 
 	if (0 <= pos)
 		/* we were tracking this path before the merge */
@@ -839,13 +839,13 @@ static int was_tracked(struct merge_options *o, const char *path)
 	return 0;
 }
 
-static int would_lose_untracked(struct merge_options *o, const char *path)
+static int would_lose_untracked(struct merge_options *opt, const char *path)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 
 	/*
 	 * This may look like it can be simplified to:
-	 *   return !was_tracked(o, path) && file_exists(path)
+	 *   return !was_tracked(opt, path) && file_exists(path)
 	 * but it can't.  This function needs to know whether path was in
 	 * the working tree due to EITHER having been tracked in the index
 	 * before the merge OR having been put into the working copy and
@@ -882,38 +882,38 @@ static int would_lose_untracked(struct merge_options *o, const char *path)
 	return file_exists(path);
 }
 
-static int was_dirty(struct merge_options *o, const char *path)
+static int was_dirty(struct merge_options *opt, const char *path)
 {
 	struct cache_entry *ce;
 	int dirty = 1;
 
-	if (o->call_depth || !was_tracked(o, path))
+	if (opt->call_depth || !was_tracked(opt, path))
 		return !dirty;
 
-	ce = index_file_exists(o->unpack_opts.src_index,
+	ce = index_file_exists(opt->unpack_opts.src_index,
 			       path, strlen(path), ignore_case);
-	dirty = verify_uptodate(ce, &o->unpack_opts) != 0;
+	dirty = verify_uptodate(ce, &opt->unpack_opts) != 0;
 	return dirty;
 }
 
-static int make_room_for_path(struct merge_options *o, const char *path)
+static int make_room_for_path(struct merge_options *opt, const char *path)
 {
 	int status, i;
 	const char *msg = _("failed to create path '%s'%s");
 
 	/* Unlink any D/F conflict files that are in the way */
-	for (i = 0; i < o->df_conflict_file_set.nr; i++) {
-		const char *df_path = o->df_conflict_file_set.items[i].string;
+	for (i = 0; i < opt->df_conflict_file_set.nr; i++) {
+		const char *df_path = opt->df_conflict_file_set.items[i].string;
 		size_t pathlen = strlen(path);
 		size_t df_pathlen = strlen(df_path);
 		if (df_pathlen < pathlen &&
 		    path[df_pathlen] == '/' &&
 		    strncmp(path, df_path, df_pathlen) == 0) {
-			output(o, 3,
+			output(opt, 3,
 			       _("Removing %s to make room for subdirectory\n"),
 			       df_path);
 			unlink(df_path);
-			unsorted_string_list_delete_item(&o->df_conflict_file_set,
+			unsorted_string_list_delete_item(&opt->df_conflict_file_set,
 							 i, 0);
 			break;
 		}
@@ -924,16 +924,16 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	if (status) {
 		if (status == SCLD_EXISTS)
 			/* something else exists */
-			return err(o, msg, path, _(": perhaps a D/F conflict?"));
-		return err(o, msg, path, "");
+			return err(opt, msg, path, _(": perhaps a D/F conflict?"));
+		return err(opt, msg, path, "");
 	}
 
 	/*
 	 * Do not unlink a file in the work tree if we are not
 	 * tracking it.
 	 */
-	if (would_lose_untracked(o, path))
-		return err(o, _("refusing to lose untracked file at '%s'"),
+	if (would_lose_untracked(opt, path))
+		return err(opt, _("refusing to lose untracked file at '%s'"),
 			   path);
 
 	/* Successful unlink is good.. */
@@ -943,10 +943,10 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	if (errno == ENOENT)
 		return 0;
 	/* .. but not some other error (who really cares what?) */
-	return err(o, msg, path, _(": perhaps a D/F conflict?"));
+	return err(opt, msg, path, _(": perhaps a D/F conflict?"));
 }
 
-static int update_file_flags(struct merge_options *o,
+static int update_file_flags(struct merge_options *opt,
 			     const struct object_id *oid,
 			     unsigned mode,
 			     const char *path,
@@ -955,7 +955,7 @@ static int update_file_flags(struct merge_options *o,
 {
 	int ret = 0;
 
-	if (o->call_depth)
+	if (opt->call_depth)
 		update_wd = 0;
 
 	if (update_wd) {
@@ -975,21 +975,21 @@ static int update_file_flags(struct merge_options *o,
 
 		buf = read_object_file(oid, &type, &size);
 		if (!buf)
-			return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
+			return err(opt, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
 		if (type != OBJ_BLOB) {
-			ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
+			ret = err(opt, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
 			goto free_buf;
 		}
 		if (S_ISREG(mode)) {
 			struct strbuf strbuf = STRBUF_INIT;
-			if (convert_to_working_tree(o->repo->index, path, buf, size, &strbuf)) {
+			if (convert_to_working_tree(opt->repo->index, path, buf, size, &strbuf)) {
 				free(buf);
 				size = strbuf.len;
 				buf = strbuf_detach(&strbuf, NULL);
 			}
 		}
 
-		if (make_room_for_path(o, path) < 0) {
+		if (make_room_for_path(opt, path) < 0) {
 			update_wd = 0;
 			goto free_buf;
 		}
@@ -1001,7 +1001,7 @@ static int update_file_flags(struct merge_options *o,
 				mode = 0666;
 			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 			if (fd < 0) {
-				ret = err(o, _("failed to open '%s': %s"),
+				ret = err(opt, _("failed to open '%s': %s"),
 					  path, strerror(errno));
 				goto free_buf;
 			}
@@ -1012,11 +1012,11 @@ static int update_file_flags(struct merge_options *o,
 			safe_create_leading_directories_const(path);
 			unlink(path);
 			if (symlink(lnk, path))
-				ret = err(o, _("failed to symlink '%s': %s"),
+				ret = err(opt, _("failed to symlink '%s': %s"),
 					  path, strerror(errno));
 			free(lnk);
 		} else
-			ret = err(o,
+			ret = err(opt,
 				  _("do not know what to do with %06o %s '%s'"),
 				  mode, oid_to_hex(oid), path);
 	free_buf:
@@ -1024,19 +1024,19 @@ static int update_file_flags(struct merge_options *o,
 	}
 update_index:
 	if (!ret && update_cache)
-		if (add_cacheinfo(o, mode, oid, path, 0, update_wd,
+		if (add_cacheinfo(opt, mode, oid, path, 0, update_wd,
 				  ADD_CACHE_OK_TO_ADD))
 			return -1;
 	return ret;
 }
 
-static int update_file(struct merge_options *o,
+static int update_file(struct merge_options *opt,
 		       int clean,
 		       const struct object_id *oid,
 		       unsigned mode,
 		       const char *path)
 {
-	return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
+	return update_file_flags(opt, oid, mode, path, opt->call_depth || clean, !opt->call_depth);
 }
 
 /* Low level file merging, update and removal */
@@ -1048,7 +1048,7 @@ struct merge_file_info {
 		 merge:1;
 };
 
-static int merge_3way(struct merge_options *o,
+static int merge_3way(struct merge_options *opt,
 		      mmbuffer_t *result_buf,
 		      const struct diff_filespec *one,
 		      const struct diff_filespec *a,
@@ -1062,15 +1062,15 @@ static int merge_3way(struct merge_options *o,
 	char *base_name, *name1, *name2;
 	int merge_status;
 
-	ll_opts.renormalize = o->renormalize;
+	ll_opts.renormalize = opt->renormalize;
 	ll_opts.extra_marker_size = extra_marker_size;
-	ll_opts.xdl_opts = o->xdl_opts;
+	ll_opts.xdl_opts = opt->xdl_opts;
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		ll_opts.virtual_ancestor = 1;
 		ll_opts.variant = 0;
 	} else {
-		switch (o->recursive_variant) {
+		switch (opt->recursive_variant) {
 		case MERGE_RECURSIVE_OURS:
 			ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 			break;
@@ -1084,14 +1084,14 @@ static int merge_3way(struct merge_options *o,
 	}
 
 	if (strcmp(a->path, b->path) ||
-	    (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
-		base_name = o->ancestor == NULL ? NULL :
-			mkpathdup("%s:%s", o->ancestor, one->path);
+	    (opt->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
+		base_name = opt->ancestor == NULL ? NULL :
+			mkpathdup("%s:%s", opt->ancestor, one->path);
 		name1 = mkpathdup("%s:%s", branch1, a->path);
 		name2 = mkpathdup("%s:%s", branch2, b->path);
 	} else {
-		base_name = o->ancestor == NULL ? NULL :
-			mkpathdup("%s", o->ancestor);
+		base_name = opt->ancestor == NULL ? NULL :
+			mkpathdup("%s", opt->ancestor);
 		name1 = mkpathdup("%s", branch1);
 		name2 = mkpathdup("%s", branch2);
 	}
@@ -1102,7 +1102,7 @@ static int merge_3way(struct merge_options *o,
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
-				o->repo->index, &ll_opts);
+				opt->repo->index, &ll_opts);
 
 	free(base_name);
 	free(name1);
@@ -1184,7 +1184,7 @@ static void print_commit(struct commit *commit)
 	strbuf_release(&sb);
 }
 
-static int merge_submodule(struct merge_options *o,
+static int merge_submodule(struct merge_options *opt,
 			   struct object_id *result, const char *path,
 			   const struct object_id *base, const struct object_id *a,
 			   const struct object_id *b)
@@ -1194,7 +1194,7 @@ static int merge_submodule(struct merge_options *o,
 	struct object_array merges;
 
 	int i;
-	int search = !o->call_depth;
+	int search = !opt->call_depth;
 
 	/* store a in result in case we fail */
 	oidcpy(result, a);
@@ -1208,32 +1208,32 @@ static int merge_submodule(struct merge_options *o,
 		return 0;
 
 	if (add_submodule_odb(path)) {
-		output(o, 1, _("Failed to merge submodule %s (not checked out)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
 		return 0;
 	}
 
-	if (!(commit_base = lookup_commit_reference(o->repo, base)) ||
-	    !(commit_a = lookup_commit_reference(o->repo, a)) ||
-	    !(commit_b = lookup_commit_reference(o->repo, b))) {
-		output(o, 1, _("Failed to merge submodule %s (commits not present)"), path);
+	if (!(commit_base = lookup_commit_reference(opt->repo, base)) ||
+	    !(commit_a = lookup_commit_reference(opt->repo, a)) ||
+	    !(commit_b = lookup_commit_reference(opt->repo, b))) {
+		output(opt, 1, _("Failed to merge submodule %s (commits not present)"), path);
 		return 0;
 	}
 
 	/* check whether both changes are forward */
 	if (!in_merge_bases(commit_base, commit_a) ||
 	    !in_merge_bases(commit_base, commit_b)) {
-		output(o, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
 		return 0;
 	}
 
 	/* Case #1: a is contained in b or vice versa */
 	if (in_merge_bases(commit_a, commit_b)) {
 		oidcpy(result, b);
-		if (show(o, 3)) {
-			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(o, commit_b);
-		} else if (show(o, 2))
-			output(o, 2, _("Fast-forwarding submodule %s"), path);
+		if (show(opt, 3)) {
+			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+			output_commit_title(opt, commit_b);
+		} else if (show(opt, 2))
+			output(opt, 2, _("Fast-forwarding submodule %s"), path);
 		else
 			; /* no output */
 
@@ -1241,11 +1241,11 @@ static int merge_submodule(struct merge_options *o,
 	}
 	if (in_merge_bases(commit_b, commit_a)) {
 		oidcpy(result, a);
-		if (show(o, 3)) {
-			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(o, commit_a);
-		} else if (show(o, 2))
-			output(o, 2, _("Fast-forwarding submodule %s"), path);
+		if (show(opt, 3)) {
+			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+			output_commit_title(opt, commit_a);
+		} else if (show(opt, 2))
+			output(opt, 2, _("Fast-forwarding submodule %s"), path);
 		else
 			; /* no output */
 
@@ -1264,18 +1264,18 @@ static int merge_submodule(struct merge_options *o,
 		return 0;
 
 	/* find commit which merges them */
-	parent_count = find_first_merges(o->repo, &merges, path,
+	parent_count = find_first_merges(opt->repo, &merges, path,
 					 commit_a, commit_b);
 	switch (parent_count) {
 	case 0:
-		output(o, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
 		break;
 
 	case 1:
-		output(o, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
-		output(o, 2, _("Found a possible merge resolution for the submodule:\n"));
+		output(opt, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
+		output(opt, 2, _("Found a possible merge resolution for the submodule:\n"));
 		print_commit((struct commit *) merges.objects[0].item);
-		output(o, 2, _(
+		output(opt, 2, _(
 		       "If this is correct simply add it to the index "
 		       "for example\n"
 		       "by using:\n\n"
@@ -1285,7 +1285,7 @@ static int merge_submodule(struct merge_options *o,
 		break;
 
 	default:
-		output(o, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
 		for (i = 0; i < merges.nr; i++)
 			print_commit((struct commit *) merges.objects[i].item);
 	}
@@ -1294,7 +1294,7 @@ static int merge_submodule(struct merge_options *o,
 	return 0;
 }
 
-static int merge_mode_and_contents(struct merge_options *o,
+static int merge_mode_and_contents(struct merge_options *opt,
 				   const struct diff_filespec *one,
 				   const struct diff_filespec *a,
 				   const struct diff_filespec *b,
@@ -1304,13 +1304,13 @@ static int merge_mode_and_contents(struct merge_options *o,
 				   const int extra_marker_size,
 				   struct merge_file_info *result)
 {
-	if (o->branch1 != branch1) {
+	if (opt->branch1 != branch1) {
 		/*
 		 * It's weird getting a reverse merge with HEAD on the bottom
 		 * side of the conflict markers and the other branch on the
 		 * top.  Fix that.
 		 */
-		return merge_mode_and_contents(o, one, b, a,
+		return merge_mode_and_contents(opt, one, b, a,
 					       filename,
 					       branch2, branch1,
 					       extra_marker_size, result);
@@ -1353,17 +1353,17 @@ static int merge_mode_and_contents(struct merge_options *o,
 			mmbuffer_t result_buf;
 			int ret = 0, merge_status;
 
-			merge_status = merge_3way(o, &result_buf, one, a, b,
+			merge_status = merge_3way(opt, &result_buf, one, a, b,
 						  branch1, branch2,
 						  extra_marker_size);
 
 			if ((merge_status < 0) || !result_buf.ptr)
-				ret = err(o, _("Failed to execute internal merge"));
+				ret = err(opt, _("Failed to execute internal merge"));
 
 			if (!ret &&
 			    write_object_file(result_buf.ptr, result_buf.size,
 					      blob_type, &result->oid))
-				ret = err(o, _("Unable to add %s to database"),
+				ret = err(opt, _("Unable to add %s to database"),
 					  a->path);
 
 			free(result_buf.ptr);
@@ -1371,13 +1371,13 @@ static int merge_mode_and_contents(struct merge_options *o,
 				return ret;
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(o, &result->oid,
+			result->clean = merge_submodule(opt, &result->oid,
 							one->path,
 							&one->oid,
 							&a->oid,
 							&b->oid);
 		} else if (S_ISLNK(a->mode)) {
-			switch (o->recursive_variant) {
+			switch (opt->recursive_variant) {
 			case MERGE_RECURSIVE_NORMAL:
 				oidcpy(&result->oid, &a->oid);
 				if (!oid_eq(&a->oid, &b->oid))
@@ -1395,12 +1395,12 @@ static int merge_mode_and_contents(struct merge_options *o,
 	}
 
 	if (result->merge)
-		output(o, 2, _("Auto-merging %s"), filename);
+		output(opt, 2, _("Auto-merging %s"), filename);
 
 	return 0;
 }
 
-static int handle_rename_via_dir(struct merge_options *o,
+static int handle_rename_via_dir(struct merge_options *opt,
 				 struct diff_filepair *pair,
 				 const char *rename_branch)
 {
@@ -1412,10 +1412,10 @@ static int handle_rename_via_dir(struct merge_options *o,
 	 */
 	const struct diff_filespec *dest = pair->two;
 
-	if (!o->call_depth && would_lose_untracked(o, dest->path)) {
-		char *alt_path = unique_path(o, dest->path, rename_branch);
+	if (!opt->call_depth && would_lose_untracked(opt, dest->path)) {
+		char *alt_path = unique_path(opt, dest->path, rename_branch);
 
-		output(o, 1, _("Error: Refusing to lose untracked file at %s; "
+		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
 			       "writing to %s instead."),
 		       dest->path, alt_path);
 		/*
@@ -1423,21 +1423,21 @@ static int handle_rename_via_dir(struct merge_options *o,
 		 * index.  Instead, write to dest->path for the index but
 		 * only at the higher appropriate stage.
 		 */
-		if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
+		if (update_file(opt, 0, &dest->oid, dest->mode, alt_path))
 			return -1;
 		free(alt_path);
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		return update_stages(opt, dest->path, NULL,
+				     rename_branch == opt->branch1 ? dest : NULL,
+				     rename_branch == opt->branch1 ? NULL : dest);
 	}
 
 	/* Update dest->path both in index and in worktree */
-	if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
+	if (update_file(opt, 1, &dest->oid, dest->mode, dest->path))
 		return -1;
 	return 0;
 }
 
-static int handle_change_delete(struct merge_options *o,
+static int handle_change_delete(struct merge_options *opt,
 				const char *path, const char *old_path,
 				const struct object_id *o_oid, int o_mode,
 				const struct object_id *changed_oid,
@@ -1450,20 +1450,20 @@ static int handle_change_delete(struct merge_options *o,
 	const char *update_path = path;
 	int ret = 0;
 
-	if (dir_in_way(o->repo->index, path, !o->call_depth, 0) ||
-	    (!o->call_depth && would_lose_untracked(o, path))) {
-		update_path = alt_path = unique_path(o, path, change_branch);
+	if (dir_in_way(opt->repo->index, path, !opt->call_depth, 0) ||
+	    (!opt->call_depth && would_lose_untracked(opt, path))) {
+		update_path = alt_path = unique_path(opt, path, change_branch);
 	}
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		/*
 		 * We cannot arbitrarily accept either a_sha or b_sha as
 		 * correct; since there is no true "middle point" between
 		 * them, simply reuse the base version for virtual merge base.
 		 */
-		ret = remove_file_from_index(o->repo->index, path);
+		ret = remove_file_from_index(opt->repo->index, path);
 		if (!ret)
-			ret = update_file(o, 0, o_oid, o_mode, update_path);
+			ret = update_file(opt, 0, o_oid, o_mode, update_path);
 	} else {
 		/*
 		 * Despite the four nearly duplicate messages and argument
@@ -1482,24 +1482,24 @@ static int handle_change_delete(struct merge_options *o,
 		 */
 		if (!alt_path) {
 			if (!old_path) {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s in %s. Version %s of %s left in tree."),
 				       change, path, delete_branch, change_past,
 				       change_branch, change_branch, path);
 			} else {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s to %s in %s. Version %s of %s left in tree."),
 				       change, old_path, delete_branch, change_past, path,
 				       change_branch, change_branch, path);
 			}
 		} else {
 			if (!old_path) {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s in %s. Version %s of %s left in tree at %s."),
 				       change, path, delete_branch, change_past,
 				       change_branch, change_branch, path, alt_path);
 			} else {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s to %s in %s. Version %s of %s left in tree at %s."),
 				       change, old_path, delete_branch, change_past, path,
 				       change_branch, change_branch, path, alt_path);
@@ -1507,19 +1507,19 @@ static int handle_change_delete(struct merge_options *o,
 		}
 		/*
 		 * No need to call update_file() on path when change_branch ==
-		 * o->branch1 && !alt_path, since that would needlessly touch
+		 * opt->branch1 && !alt_path, since that would needlessly touch
 		 * path.  We could call update_file_flags() with update_cache=0
 		 * and update_wd=0, but that's a no-op.
 		 */
-		if (change_branch != o->branch1 || alt_path)
-			ret = update_file(o, 0, changed_oid, changed_mode, update_path);
+		if (change_branch != opt->branch1 || alt_path)
+			ret = update_file(opt, 0, changed_oid, changed_mode, update_path);
 	}
 	free(alt_path);
 
 	return ret;
 }
 
-static int handle_rename_delete(struct merge_options *o,
+static int handle_rename_delete(struct merge_options *opt,
 				struct diff_filepair *pair,
 				const char *rename_branch,
 				const char *delete_branch)
@@ -1527,21 +1527,21 @@ static int handle_rename_delete(struct merge_options *o,
 	const struct diff_filespec *orig = pair->one;
 	const struct diff_filespec *dest = pair->two;
 
-	if (handle_change_delete(o,
-				 o->call_depth ? orig->path : dest->path,
-				 o->call_depth ? NULL : orig->path,
+	if (handle_change_delete(opt,
+				 opt->call_depth ? orig->path : dest->path,
+				 opt->call_depth ? NULL : orig->path,
 				 &orig->oid, orig->mode,
 				 &dest->oid, dest->mode,
 				 rename_branch, delete_branch,
 				 _("rename"), _("renamed")))
 		return -1;
 
-	if (o->call_depth)
-		return remove_file_from_index(o->repo->index, dest->path);
+	if (opt->call_depth)
+		return remove_file_from_index(opt->repo->index, dest->path);
 	else
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		return update_stages(opt, dest->path, NULL,
+				     rename_branch == opt->branch1 ? dest : NULL,
+				     rename_branch == opt->branch1 ? NULL : dest);
 }
 
 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
@@ -1557,7 +1557,7 @@ static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
 	return target;
 }
 
-static int handle_file_collision(struct merge_options *o,
+static int handle_file_collision(struct merge_options *opt,
 				 const char *collide_path,
 				 const char *prev_path1,
 				 const char *prev_path2,
@@ -1575,11 +1575,11 @@ static int handle_file_collision(struct merge_options *o,
 	/*
 	 * It's easiest to get the correct things into stage 2 and 3, and
 	 * to make sure that the content merge puts HEAD before the other
-	 * branch if we just ensure that branch1 == o->branch1.  So, simply
+	 * branch if we just ensure that branch1 == opt->branch1.  So, simply
 	 * flip arguments around if we don't have that.
 	 */
-	if (branch1 != o->branch1) {
-		return handle_file_collision(o, collide_path,
+	if (branch1 != opt->branch1) {
+		return handle_file_collision(opt, collide_path,
 					     prev_path2, prev_path1,
 					     branch2, branch1,
 					     b_oid, b_mode,
@@ -1589,60 +1589,60 @@ static int handle_file_collision(struct merge_options *o,
 	/*
 	 * In the recursive case, we just opt to undo renames
 	 */
-	if (o->call_depth && (prev_path1 || prev_path2)) {
+	if (opt->call_depth && (prev_path1 || prev_path2)) {
 		/* Put first file (a_oid, a_mode) in its original spot */
 		if (prev_path1) {
-			if (update_file(o, 1, a_oid, a_mode, prev_path1))
+			if (update_file(opt, 1, a_oid, a_mode, prev_path1))
 				return -1;
 		} else {
-			if (update_file(o, 1, a_oid, a_mode, collide_path))
+			if (update_file(opt, 1, a_oid, a_mode, collide_path))
 				return -1;
 		}
 
 		/* Put second file (b_oid, b_mode) in its original spot */
 		if (prev_path2) {
-			if (update_file(o, 1, b_oid, b_mode, prev_path2))
+			if (update_file(opt, 1, b_oid, b_mode, prev_path2))
 				return -1;
 		} else {
-			if (update_file(o, 1, b_oid, b_mode, collide_path))
+			if (update_file(opt, 1, b_oid, b_mode, collide_path))
 				return -1;
 		}
 
 		/* Don't leave something at collision path if unrenaming both */
 		if (prev_path1 && prev_path2)
-			remove_file(o, 1, collide_path, 0);
+			remove_file(opt, 1, collide_path, 0);
 
 		return 0;
 	}
 
 	/* Remove rename sources if rename/add or rename/rename(2to1) */
 	if (prev_path1)
-		remove_file(o, 1, prev_path1,
-			    o->call_depth || would_lose_untracked(o, prev_path1));
+		remove_file(opt, 1, prev_path1,
+			    opt->call_depth || would_lose_untracked(opt, prev_path1));
 	if (prev_path2)
-		remove_file(o, 1, prev_path2,
-			    o->call_depth || would_lose_untracked(o, prev_path2));
+		remove_file(opt, 1, prev_path2,
+			    opt->call_depth || would_lose_untracked(opt, prev_path2));
 
 	/*
 	 * Remove the collision path, if it wouldn't cause dirty contents
 	 * or an untracked file to get lost.  We'll either overwrite with
 	 * merged contents, or just write out to differently named files.
 	 */
-	if (was_dirty(o, collide_path)) {
-		output(o, 1, _("Refusing to lose dirty file at %s"),
+	if (was_dirty(opt, collide_path)) {
+		output(opt, 1, _("Refusing to lose dirty file at %s"),
 		       collide_path);
-		update_path = alt_path = unique_path(o, collide_path, "merged");
-	} else if (would_lose_untracked(o, collide_path)) {
+		update_path = alt_path = unique_path(opt, collide_path, "merged");
+	} else if (would_lose_untracked(opt, collide_path)) {
 		/*
 		 * Only way we get here is if both renames were from
 		 * a directory rename AND user had an untracked file
 		 * at the location where both files end up after the
 		 * two directory renames.  See testcase 10d of t6043.
 		 */
-		output(o, 1, _("Refusing to lose untracked file at "
+		output(opt, 1, _("Refusing to lose untracked file at "
 			       "%s, even though it's in the way."),
 		       collide_path);
-		update_path = alt_path = unique_path(o, collide_path, "merged");
+		update_path = alt_path = unique_path(opt, collide_path, "merged");
 	} else {
 		/*
 		 * FIXME: It's possible that the two files are identical
@@ -1654,7 +1654,7 @@ static int handle_file_collision(struct merge_options *o,
 		 * merge-recursive interoperate anyway, so punting for
 		 * now...
 		 */
-		remove_file(o, 0, collide_path, 0);
+		remove_file(opt, 0, collide_path, 0);
 	}
 
 	/* Store things in diff_filespecs for functions that need it */
@@ -1670,14 +1670,14 @@ static int handle_file_collision(struct merge_options *o,
 	b.mode = b_mode;
 	b.oid_valid = 1;
 
-	if (merge_mode_and_contents(o, &null, &a, &b, collide_path,
-				    branch1, branch2, o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, &null, &a, &b, collide_path,
+				    branch1, branch2, opt->call_depth * 2, &mfi))
 		return -1;
 	mfi.clean &= !alt_path;
-	if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, update_path))
+	if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, update_path))
 		return -1;
-	if (!mfi.clean && !o->call_depth &&
-	    update_stages(o, collide_path, NULL, &a, &b))
+	if (!mfi.clean && !opt->call_depth &&
+	    update_stages(opt, collide_path, NULL, &a, &b))
 		return -1;
 	free(alt_path);
 	/*
@@ -1690,7 +1690,7 @@ static int handle_file_collision(struct merge_options *o,
 	return mfi.clean;
 }
 
-static int handle_rename_add(struct merge_options *o,
+static int handle_rename_add(struct merge_options *opt,
 			     struct rename_conflict_info *ci)
 {
 	/* a was renamed to c, and a separate c was added. */
@@ -1700,21 +1700,21 @@ static int handle_rename_add(struct merge_options *o,
 	char *prev_path_desc;
 	struct merge_file_info mfi;
 
-	int other_stage = (ci->branch1 == o->branch1 ? 3 : 2);
+	int other_stage = (ci->branch1 == opt->branch1 ? 3 : 2);
 
-	output(o, 1, _("CONFLICT (rename/add): "
+	output(opt, 1, _("CONFLICT (rename/add): "
 	       "Rename %s->%s in %s.  Added %s in %s"),
 	       a->path, c->path, ci->branch1,
 	       c->path, ci->branch2);
 
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(o, a, c, &ci->ren1_other, prev_path_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, a, c, &ci->ren1_other, prev_path_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi))
 		return -1;
 	free(prev_path_desc);
 
-	return handle_file_collision(o,
+	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
 				     ci->branch1, ci->branch2,
 				     &mfi.oid, mfi.mode,
@@ -1722,20 +1722,20 @@ static int handle_rename_add(struct merge_options *o,
 				     ci->dst_entry1->stages[other_stage].mode);
 }
 
-static char *find_path_for_conflict(struct merge_options *o,
+static char *find_path_for_conflict(struct merge_options *opt,
 				    const char *path,
 				    const char *branch1,
 				    const char *branch2)
 {
 	char *new_path = NULL;
-	if (dir_in_way(o->repo->index, path, !o->call_depth, 0)) {
-		new_path = unique_path(o, path, branch1);
-		output(o, 1, _("%s is a directory in %s adding "
+	if (dir_in_way(opt->repo->index, path, !opt->call_depth, 0)) {
+		new_path = unique_path(opt, path, branch1);
+		output(opt, 1, _("%s is a directory in %s adding "
 			       "as %s instead"),
 		       path, branch2, new_path);
-	} else if (would_lose_untracked(o, path)) {
-		new_path = unique_path(o, path, branch1);
-		output(o, 1, _("Refusing to lose untracked file"
+	} else if (would_lose_untracked(opt, path)) {
+		new_path = unique_path(opt, path, branch1);
+		output(opt, 1, _("Refusing to lose untracked file"
 			       " at %s; adding as %s instead"),
 		       path, new_path);
 	}
@@ -1743,7 +1743,7 @@ static char *find_path_for_conflict(struct merge_options *o,
 	return new_path;
 }
 
-static int handle_rename_rename_1to2(struct merge_options *o,
+static int handle_rename_rename_1to2(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
 	/* One file was renamed in both branches, but to different names. */
@@ -1755,29 +1755,29 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 	struct diff_filespec *b = ci->pair2->two;
 	char *path_desc;
 
-	output(o, 1, _("CONFLICT (rename/rename): "
+	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
 	       one->path, a->path, ci->branch1,
 	       one->path, b->path, ci->branch2,
-	       o->call_depth ? _(" (left unresolved)") : "");
+	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
 			    a->path, b->path, one->path);
-	if (merge_mode_and_contents(o, one, a, b, path_desc,
+	if (merge_mode_and_contents(opt, one, a, b, path_desc,
 				    ci->branch1, ci->branch2,
-				    o->call_depth * 2, &mfi))
+				    opt->call_depth * 2, &mfi))
 		return -1;
 	free(path_desc);
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		/*
 		 * FIXME: For rename/add-source conflicts (if we could detect
 		 * such), this is wrong.  We should instead find a unique
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
+		if (update_file(opt, 0, &mfi.oid, mfi.mode, one->path))
 			return -1;
 
 		/*
@@ -1790,18 +1790,18 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 		 */
 		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
 		if (add) {
-			if (update_file(o, 0, &add->oid, add->mode, a->path))
+			if (update_file(opt, 0, &add->oid, add->mode, a->path))
 				return -1;
 		}
 		else
-			remove_file_from_index(o->repo->index, a->path);
+			remove_file_from_index(opt->repo->index, a->path);
 		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
 		if (add) {
-			if (update_file(o, 0, &add->oid, add->mode, b->path))
+			if (update_file(opt, 0, &add->oid, add->mode, b->path))
 				return -1;
 		}
 		else
-			remove_file_from_index(o->repo->index, b->path);
+			remove_file_from_index(opt->repo->index, b->path);
 	} else {
 		/*
 		 * For each destination path, we need to see if there is a
@@ -1810,39 +1810,39 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 		 */
 		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
 		if (add) {
-			if (handle_file_collision(o, a->path,
+			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
 						  ci->branch1, ci->branch2,
 						  &mfi.oid, mfi.mode,
 						  &add->oid, add->mode) < 0)
 				return -1;
 		} else {
-			char *new_path = find_path_for_conflict(o, a->path,
+			char *new_path = find_path_for_conflict(opt, a->path,
 								ci->branch1,
 								ci->branch2);
-			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
+			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
-			if (update_stages(o, a->path, NULL, a, NULL))
+			if (update_stages(opt, a->path, NULL, a, NULL))
 				return -1;
 		}
 
 		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
 		if (add) {
-			if (handle_file_collision(o, b->path,
+			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
 						  ci->branch1, ci->branch2,
 						  &add->oid, add->mode,
 						  &mfi.oid, mfi.mode) < 0)
 				return -1;
 		} else {
-			char *new_path = find_path_for_conflict(o, b->path,
+			char *new_path = find_path_for_conflict(opt, b->path,
 								ci->branch2,
 								ci->branch1);
-			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
+			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
 				return -1;
 			free(new_path);
-			if (update_stages(o, b->path, NULL, NULL, b))
+			if (update_stages(opt, b->path, NULL, NULL, b))
 				return -1;
 		}
 	}
@@ -1850,7 +1850,7 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 	return 0;
 }
 
-static int handle_rename_rename_2to1(struct merge_options *o,
+static int handle_rename_rename_2to1(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
 	/* Two files, a & b, were renamed to the same thing, c. */
@@ -1864,7 +1864,7 @@ static int handle_rename_rename_2to1(struct merge_options *o,
 	struct merge_file_info mfi_c1;
 	struct merge_file_info mfi_c2;
 
-	output(o, 1, _("CONFLICT (rename/rename): "
+	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
 	       "Rename %s->%s in %s"),
 	       a->path, c1->path, ci->branch1,
@@ -1872,17 +1872,17 @@ static int handle_rename_rename_2to1(struct merge_options *o,
 
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	if (merge_mode_and_contents(o, a, c1, &ci->ren1_other, path_side_1_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(o, b, &ci->ren2_other, c2, path_side_2_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi_c2))
+	if (merge_mode_and_contents(opt, a, c1, &ci->ren1_other, path_side_1_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi_c1) ||
+	    merge_mode_and_contents(opt, b, &ci->ren2_other, c2, path_side_2_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi_c2))
 		return -1;
 	free(path_side_1_desc);
 	free(path_side_2_desc);
 
-	return handle_file_collision(o, path, a->path, b->path,
+	return handle_file_collision(opt, path, a->path, b->path,
 				     ci->branch1, ci->branch2,
 				     &mfi_c1.oid, mfi_c1.mode,
 				     &mfi_c2.oid, mfi_c2.mode);
@@ -1891,17 +1891,17 @@ static int handle_rename_rename_2to1(struct merge_options *o,
 /*
  * Get the diff_filepairs changed between o_tree and tree.
  */
-static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
+static struct diff_queue_struct *get_diffpairs(struct merge_options *opt,
 					       struct tree *o_tree,
 					       struct tree *tree)
 {
 	struct diff_queue_struct *ret;
 	struct diff_options opts;
 
-	repo_diff_setup(o->repo, &opts);
+	repo_diff_setup(opt->repo, &opts);
 	opts.flags.recursive = 1;
 	opts.flags.rename_empty = 0;
-	opts.detect_rename = merge_detect_rename(o);
+	opts.detect_rename = merge_detect_rename(opt);
 	/*
 	 * We do not have logic to handle the detection of copies.  In
 	 * fact, it may not even make sense to add such logic: would we
@@ -1910,17 +1910,17 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 	 */
 	if (opts.detect_rename > DIFF_DETECT_RENAME)
 		opts.detect_rename = DIFF_DETECT_RENAME;
-	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
-			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
+	opts.rename_limit = opt->merge_rename_limit >= 0 ? opt->merge_rename_limit :
+			    opt->diff_rename_limit >= 0 ? opt->diff_rename_limit :
 			    1000;
-	opts.rename_score = o->rename_score;
-	opts.show_rename_progress = o->show_rename_progress;
+	opts.rename_score = opt->rename_score;
+	opts.show_rename_progress = opt->show_rename_progress;
 	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 	diff_setup_done(&opts);
 	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
 	diffcore_std(&opts);
-	if (opts.needed_rename_limit > o->needed_rename_limit)
-		o->needed_rename_limit = opts.needed_rename_limit;
+	if (opts.needed_rename_limit > opt->needed_rename_limit)
+		opt->needed_rename_limit = opts.needed_rename_limit;
 
 	ret = xmalloc(sizeof(*ret));
 	*ret = diff_queued_diff;
@@ -2039,7 +2039,7 @@ static void remove_hashmap_entries(struct hashmap *dir_renames,
  * level conflicts for the renamed location.  If there is a rename and
  * there are no conflicts, return the new name.  Otherwise, return NULL.
  */
-static char *handle_path_level_conflicts(struct merge_options *o,
+static char *handle_path_level_conflicts(struct merge_options *opt,
 					 const char *path,
 					 struct dir_rename_entry *entry,
 					 struct hashmap *collisions,
@@ -2060,7 +2060,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		/* This should only happen when entry->non_unique_new_dir set */
 		if (!entry->non_unique_new_dir)
 			BUG("entry->non_unqiue_dir not set and !new_path");
-		output(o, 1, _("CONFLICT (directory rename split): "
+		output(opt, 1, _("CONFLICT (directory rename split): "
 			       "Unclear where to place %s because directory "
 			       "%s was renamed to multiple other directories, "
 			       "with no destination getting a majority of the "
@@ -2092,7 +2092,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		collision_ent->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &collision_ent->source_files);
-		output(o, 1, _("CONFLICT (implicit dir rename): Existing "
+		output(opt, 1, _("CONFLICT (implicit dir rename): Existing "
 			       "file/dir at %s in the way of implicit "
 			       "directory rename(s) putting the following "
 			       "path(s) there: %s."),
@@ -2102,7 +2102,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		collision_ent->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &collision_ent->source_files);
-		output(o, 1, _("CONFLICT (implicit dir rename): Cannot map "
+		output(opt, 1, _("CONFLICT (implicit dir rename): Cannot map "
 			       "more than one path to %s; implicit directory "
 			       "renames tried to put these paths there: %s"),
 		       new_path, collision_paths.buf);
@@ -2139,7 +2139,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
  *         causes conflicts for files within those merged directories, then
  *         that should be detected at the individual path level.
  */
-static void handle_directory_level_conflicts(struct merge_options *o,
+static void handle_directory_level_conflicts(struct merge_options *opt,
 					     struct hashmap *dir_re_head,
 					     struct tree *head,
 					     struct hashmap *dir_re_merge,
@@ -2194,11 +2194,11 @@ static void handle_directory_level_conflicts(struct merge_options *o,
 			 * know that head_ent->new_dir and merge_ent->new_dir
 			 * are different strings.
 			 */
-			output(o, 1, _("CONFLICT (rename/rename): "
+			output(opt, 1, _("CONFLICT (rename/rename): "
 				       "Rename directory %s->%s in %s. "
 				       "Rename directory %s->%s in %s"),
-			       head_ent->dir, head_ent->new_dir.buf, o->branch1,
-			       head_ent->dir, merge_ent->new_dir.buf, o->branch2);
+			       head_ent->dir, head_ent->new_dir.buf, opt->branch1,
+			       head_ent->dir, merge_ent->new_dir.buf, opt->branch2);
 			string_list_append(&remove_from_head,
 					   head_ent->dir)->util = head_ent;
 			strbuf_release(&head_ent->new_dir);
@@ -2397,7 +2397,7 @@ static void compute_collisions(struct hashmap *collisions,
 	}
 }
 
-static char *check_for_directory_rename(struct merge_options *o,
+static char *check_for_directory_rename(struct merge_options *opt,
 					const char *path,
 					struct tree *tree,
 					struct hashmap *dir_renames,
@@ -2438,11 +2438,11 @@ static char *check_for_directory_rename(struct merge_options *o,
 	 */
 	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
 	if (oentry) {
-		output(o, 1, _("WARNING: Avoiding applying %s -> %s rename "
+		output(opt, 1, _("WARNING: Avoiding applying %s -> %s rename "
 			       "to %s, because %s itself was renamed."),
 		       entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
 	} else {
-		new_path = handle_path_level_conflicts(o, path, entry,
+		new_path = handle_path_level_conflicts(opt, path, entry,
 						       collisions, tree);
 		*clean_merge &= (new_path != NULL);
 	}
@@ -2450,7 +2450,7 @@ static char *check_for_directory_rename(struct merge_options *o,
 	return new_path;
 }
 
-static void apply_directory_rename_modifications(struct merge_options *o,
+static void apply_directory_rename_modifications(struct merge_options *opt,
 						 struct diff_filepair *pair,
 						 char *new_path,
 						 struct rename *re,
@@ -2473,11 +2473,11 @@ static void apply_directory_rename_modifications(struct merge_options *o,
 	 * saying the file would have been overwritten), but it might
 	 * be dirty, though.
 	 */
-	update_wd = !was_dirty(o, pair->two->path);
+	update_wd = !was_dirty(opt, pair->two->path);
 	if (!update_wd)
-		output(o, 1, _("Refusing to lose dirty file at %s"),
+		output(opt, 1, _("Refusing to lose dirty file at %s"),
 		       pair->two->path);
-	remove_file(o, 1, pair->two->path, !update_wd);
+	remove_file(opt, 1, pair->two->path, !update_wd);
 
 	/* Find or create a new re->dst_entry */
 	item = string_list_lookup(entries, new_path);
@@ -2566,7 +2566,7 @@ static void apply_directory_rename_modifications(struct merge_options *o,
  * to be able to associate the correct cache entries with the rename
  * information; tree is always equal to either a_tree or b_tree.
  */
-static struct string_list *get_renames(struct merge_options *o,
+static struct string_list *get_renames(struct merge_options *opt,
 				       struct diff_queue_struct *pairs,
 				       struct hashmap *dir_renames,
 				       struct hashmap *dir_rename_exclusions,
@@ -2596,7 +2596,7 @@ static struct string_list *get_renames(struct merge_options *o,
 			diff_free_filepair(pair);
 			continue;
 		}
-		new_path = check_for_directory_rename(o, pair->two->path, tree,
+		new_path = check_for_directory_rename(opt, pair->two->path, tree,
 						      dir_renames,
 						      dir_rename_exclusions,
 						      &collisions,
@@ -2626,7 +2626,7 @@ static struct string_list *get_renames(struct merge_options *o,
 		item = string_list_insert(renames, pair->one->path);
 		item->util = re;
 		if (new_path)
-			apply_directory_rename_modifications(o, pair, new_path,
+			apply_directory_rename_modifications(opt, pair, new_path,
 							     re, tree, o_tree,
 							     a_tree, b_tree,
 							     entries);
@@ -2641,7 +2641,7 @@ static struct string_list *get_renames(struct merge_options *o,
 	return renames;
 }
 
-static int process_renames(struct merge_options *o,
+static int process_renames(struct merge_options *opt,
 			   struct string_list *a_renames,
 			   struct string_list *b_renames)
 {
@@ -2685,13 +2685,13 @@ static int process_renames(struct merge_options *o,
 		if (ren1) {
 			renames1 = a_renames;
 			renames2Dst = &b_by_dst;
-			branch1 = o->branch1;
-			branch2 = o->branch2;
+			branch1 = opt->branch1;
+			branch2 = opt->branch2;
 		} else {
 			renames1 = b_renames;
 			renames2Dst = &a_by_dst;
-			branch1 = o->branch2;
-			branch2 = o->branch1;
+			branch1 = opt->branch2;
+			branch2 = opt->branch1;
 			SWAP(ren2, ren1);
 		}
 
@@ -2725,7 +2725,7 @@ static int process_renames(struct merge_options *o,
 				 * the base stage (think of rename +
 				 * add-source cases).
 				 */
-				remove_file(o, 1, ren1_src, 1);
+				remove_file(opt, 1, ren1_src, 1);
 				update_entry(ren1->dst_entry,
 					     ren1->pair->one,
 					     ren1->pair->two,
@@ -2738,7 +2738,7 @@ static int process_renames(struct merge_options *o,
 						   branch2,
 						   ren1->dst_entry,
 						   ren2->dst_entry,
-						   o,
+						   opt,
 						   NULL,
 						   NULL);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
@@ -2765,7 +2765,7 @@ static int process_renames(struct merge_options *o,
 						   branch2,
 						   ren1->dst_entry,
 						   ren2->dst_entry,
-						   o,
+						   opt,
 						   ren1->src_entry,
 						   ren2->src_entry);
 
@@ -2788,8 +2788,8 @@ static int process_renames(struct merge_options *o,
 			 * stage and in other_stage (think of rename +
 			 * add-source case).
 			 */
-			remove_file(o, 1, ren1_src,
-				    renamed_stage == 2 || !was_tracked(o, ren1_src));
+			remove_file(opt, 1, ren1_src,
+				    renamed_stage == 2 || !was_tracked(opt, ren1_src));
 
 			oidcpy(&src_other.oid,
 			       &ren1->src_entry->stages[other_stage].oid);
@@ -2808,7 +2808,7 @@ static int process_renames(struct merge_options *o,
 							   branch2,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   NULL,
 							   NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
@@ -2819,7 +2819,7 @@ static int process_renames(struct merge_options *o,
 							   branch2,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   NULL,
 							   NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
@@ -2832,7 +2832,7 @@ static int process_renames(struct merge_options *o,
 				 * update_file_flags() instead of
 				 * update_file().
 				 */
-				if (update_file_flags(o,
+				if (update_file_flags(opt,
 						      &ren1->pair->two->oid,
 						      ren1->pair->two->mode,
 						      ren1_dst,
@@ -2854,7 +2854,7 @@ static int process_renames(struct merge_options *o,
 							   branch2,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   ren1->src_entry,
 							   NULL);
 			} else
@@ -2882,7 +2882,7 @@ static int process_renames(struct merge_options *o,
 							   NULL,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   NULL,
 							   NULL);
 			}
@@ -2919,7 +2919,7 @@ static void initial_cleanup_rename(struct diff_queue_struct *pairs,
 	free(pairs);
 }
 
-static int detect_and_process_renames(struct merge_options *o,
+static int detect_and_process_renames(struct merge_options *opt,
 				      struct tree *common,
 				      struct tree *head,
 				      struct tree *merge,
@@ -2933,17 +2933,17 @@ static int detect_and_process_renames(struct merge_options *o,
 	ri->head_renames = NULL;
 	ri->merge_renames = NULL;
 
-	if (!merge_detect_rename(o))
+	if (!merge_detect_rename(opt))
 		return 1;
 
-	head_pairs = get_diffpairs(o, common, head);
-	merge_pairs = get_diffpairs(o, common, merge);
+	head_pairs = get_diffpairs(opt, common, head);
+	merge_pairs = get_diffpairs(opt, common, merge);
 
-	if (o->detect_directory_renames) {
+	if (opt->detect_directory_renames) {
 		dir_re_head = get_directory_renames(head_pairs);
 		dir_re_merge = get_directory_renames(merge_pairs);
 
-		handle_directory_level_conflicts(o,
+		handle_directory_level_conflicts(opt,
 						 dir_re_head, head,
 						 dir_re_merge, merge);
 	} else {
@@ -2953,19 +2953,19 @@ static int detect_and_process_renames(struct merge_options *o,
 		dir_rename_init(dir_re_merge);
 	}
 
-	ri->head_renames  = get_renames(o, head_pairs,
+	ri->head_renames  = get_renames(opt, head_pairs,
 					dir_re_merge, dir_re_head, head,
 					common, head, merge, entries,
 					&clean);
 	if (clean < 0)
 		goto cleanup;
-	ri->merge_renames = get_renames(o, merge_pairs,
+	ri->merge_renames = get_renames(opt, merge_pairs,
 					dir_re_head, dir_re_merge, merge,
 					common, head, merge, entries,
 					&clean);
 	if (clean < 0)
 		goto cleanup;
-	clean &= process_renames(o, ri->head_renames, ri->merge_renames);
+	clean &= process_renames(opt, ri->head_renames, ri->merge_renames);
 
 cleanup:
 	/*
@@ -3006,7 +3006,7 @@ static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
 	return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
 }
 
-static int read_oid_strbuf(struct merge_options *o,
+static int read_oid_strbuf(struct merge_options *opt,
 			   const struct object_id *oid,
 			   struct strbuf *dst)
 {
@@ -3015,10 +3015,10 @@ static int read_oid_strbuf(struct merge_options *o,
 	unsigned long size;
 	buf = read_object_file(oid, &type, &size);
 	if (!buf)
-		return err(o, _("cannot read object %s"), oid_to_hex(oid));
+		return err(opt, _("cannot read object %s"), oid_to_hex(oid));
 	if (type != OBJ_BLOB) {
 		free(buf);
-		return err(o, _("object %s is not a blob"), oid_to_hex(oid));
+		return err(opt, _("object %s is not a blob"), oid_to_hex(oid));
 	}
 	strbuf_attach(dst, buf, size, size + 1);
 	return 0;
@@ -3060,7 +3060,7 @@ static int blob_unchanged(struct merge_options *opt,
 	return ret;
 }
 
-static int handle_modify_delete(struct merge_options *o,
+static int handle_modify_delete(struct merge_options *opt,
 				const char *path,
 				struct object_id *o_oid, int o_mode,
 				struct object_id *a_oid, int a_mode,
@@ -3071,18 +3071,18 @@ static int handle_modify_delete(struct merge_options *o,
 	int changed_mode;
 
 	if (a_oid) {
-		modify_branch = o->branch1;
-		delete_branch = o->branch2;
+		modify_branch = opt->branch1;
+		delete_branch = opt->branch2;
 		changed_oid = a_oid;
 		changed_mode = a_mode;
 	} else {
-		modify_branch = o->branch2;
-		delete_branch = o->branch1;
+		modify_branch = opt->branch2;
+		delete_branch = opt->branch1;
 		changed_oid = b_oid;
 		changed_mode = b_mode;
 	}
 
-	return handle_change_delete(o,
+	return handle_change_delete(opt,
 				    path, NULL,
 				    o_oid, o_mode,
 				    changed_oid, changed_mode,
@@ -3090,7 +3090,7 @@ static int handle_modify_delete(struct merge_options *o,
 				    _("modify"), _("modified"));
 }
 
-static int handle_content_merge(struct merge_options *o,
+static int handle_content_merge(struct merge_options *opt,
 				const char *path,
 				int is_dirty,
 				struct object_id *o_oid, int o_mode,
@@ -3119,26 +3119,26 @@ static int handle_content_merge(struct merge_options *o,
 	if (rename_conflict_info) {
 		struct diff_filepair *pair1 = rename_conflict_info->pair1;
 
-		path1 = (o->branch1 == rename_conflict_info->branch1) ?
+		path1 = (opt->branch1 == rename_conflict_info->branch1) ?
 			pair1->two->path : pair1->one->path;
 		/* If rename_conflict_info->pair2 != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
 		path2 = (rename_conflict_info->pair2 ||
-			 o->branch2 == rename_conflict_info->branch1) ?
+			 opt->branch2 == rename_conflict_info->branch1) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
 		a.path = (char *)path1;
 		b.path = (char *)path2;
 
-		if (dir_in_way(o->repo->index, path, !o->call_depth,
+		if (dir_in_way(opt->repo->index, path, !opt->call_depth,
 			       S_ISGITLINK(pair1->two->mode)))
 			df_conflict_remains = 1;
 	}
-	if (merge_mode_and_contents(o, &one, &a, &b, path,
-				    o->branch1, o->branch2,
-				    o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, &one, &a, &b, path,
+				    opt->branch1, opt->branch2,
+				    opt->call_depth * 2, &mfi))
 		return -1;
 
 	/*
@@ -3148,14 +3148,14 @@ static int handle_content_merge(struct merge_options *o,
 	 *   c) The target path is usable (i.e. not involved in D/F conflict)
 	 */
 	if (mfi.clean &&
-	    was_tracked_and_matches(o, path, &mfi.oid, mfi.mode) &&
+	    was_tracked_and_matches(opt, path, &mfi.oid, mfi.mode) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
-		output(o, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(o, mfi.mode, &mfi.oid, path,
-				  0, (!o->call_depth && !is_dirty), 0))
+		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
+		if (add_cacheinfo(opt, mfi.mode, &mfi.oid, path,
+				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
 		 * However, add_cacheinfo() will delete the old cache entry
@@ -3163,11 +3163,11 @@ static int handle_content_merge(struct merge_options *o,
 		 * flag to avoid making the file appear as if it were
 		 * deleted by the user.
 		 */
-		pos = index_name_pos(&o->orig_index, path, strlen(path));
-		ce = o->orig_index.cache[pos];
+		pos = index_name_pos(&opt->orig_index, path, strlen(path));
+		ce = opt->orig_index.cache[pos];
 		if (ce_skip_worktree(ce)) {
-			pos = index_name_pos(o->repo->index, path, strlen(path));
-			ce = o->repo->index->cache[pos];
+			pos = index_name_pos(opt->repo->index, path, strlen(path));
+			ce = opt->repo->index->cache[pos];
 			ce->ce_flags |= CE_SKIP_WORKTREE;
 		}
 		return mfi.clean;
@@ -3176,52 +3176,52 @@ static int handle_content_merge(struct merge_options *o,
 	if (!mfi.clean) {
 		if (S_ISGITLINK(mfi.mode))
 			reason = _("submodule");
-		output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
+		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
 		if (rename_conflict_info && !df_conflict_remains)
-			if (update_stages(o, path, &one, &a, &b))
+			if (update_stages(opt, path, &one, &a, &b))
 				return -1;
 	}
 
 	if (df_conflict_remains || is_dirty) {
 		char *new_path;
-		if (o->call_depth) {
-			remove_file_from_index(o->repo->index, path);
+		if (opt->call_depth) {
+			remove_file_from_index(opt->repo->index, path);
 		} else {
 			if (!mfi.clean) {
-				if (update_stages(o, path, &one, &a, &b))
+				if (update_stages(opt, path, &one, &a, &b))
 					return -1;
 			} else {
-				int file_from_stage2 = was_tracked(o, path);
+				int file_from_stage2 = was_tracked(opt, path);
 				struct diff_filespec merged;
 				oidcpy(&merged.oid, &mfi.oid);
 				merged.mode = mfi.mode;
 
-				if (update_stages(o, path, NULL,
+				if (update_stages(opt, path, NULL,
 						  file_from_stage2 ? &merged : NULL,
 						  file_from_stage2 ? NULL : &merged))
 					return -1;
 			}
 
 		}
-		new_path = unique_path(o, path, rename_conflict_info->branch1);
+		new_path = unique_path(opt, path, rename_conflict_info->branch1);
 		if (is_dirty) {
-			output(o, 1, _("Refusing to lose dirty file at %s"),
+			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
 		}
-		output(o, 1, _("Adding as %s instead"), new_path);
-		if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
+		output(opt, 1, _("Adding as %s instead"), new_path);
+		if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path)) {
 			free(new_path);
 			return -1;
 		}
 		free(new_path);
 		mfi.clean = 0;
-	} else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
+	} else if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, path))
 		return -1;
 	return !is_dirty && mfi.clean;
 }
 
-static int handle_rename_normal(struct merge_options *o,
+static int handle_rename_normal(struct merge_options *opt,
 				const char *path,
 				struct object_id *o_oid, unsigned int o_mode,
 				struct object_id *a_oid, unsigned int a_mode,
@@ -3229,17 +3229,17 @@ static int handle_rename_normal(struct merge_options *o,
 				struct rename_conflict_info *ci)
 {
 	/* Merge the content and write it out */
-	return handle_content_merge(o, path, was_dirty(o, path),
+	return handle_content_merge(opt, path, was_dirty(opt, path),
 				    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
 				    ci);
 }
 
 /* Per entry merge function */
-static int process_entry(struct merge_options *o,
+static int process_entry(struct merge_options *opt,
 			 const char *path, struct stage_data *entry)
 {
 	int clean_merge = 1;
-	int normalize = o->renormalize;
+	int normalize = opt->renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -3253,7 +3253,7 @@ static int process_entry(struct merge_options *o,
 		switch (conflict_info->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
-			clean_merge = handle_rename_normal(o,
+			clean_merge = handle_rename_normal(opt,
 							   path,
 							   o_oid, o_mode,
 							   a_oid, a_mode,
@@ -3262,7 +3262,7 @@ static int process_entry(struct merge_options *o,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(o,
+			if (handle_rename_via_dir(opt,
 						  conflict_info->pair1,
 						  conflict_info->branch1))
 				clean_merge = -1;
@@ -3274,11 +3274,11 @@ static int process_entry(struct merge_options *o,
 			 * two-way merged cleanly with the added file, I
 			 * guess it's a clean merge?
 			 */
-			clean_merge = handle_rename_add(o, conflict_info);
+			clean_merge = handle_rename_add(opt, conflict_info);
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(o,
+			if (handle_rename_delete(opt,
 						 conflict_info->pair1,
 						 conflict_info->branch1,
 						 conflict_info->branch2))
@@ -3286,7 +3286,7 @@ static int process_entry(struct merge_options *o,
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
 			clean_merge = 0;
-			if (handle_rename_rename_1to2(o, conflict_info))
+			if (handle_rename_rename_1to2(opt, conflict_info))
 				clean_merge = -1;
 			break;
 		case RENAME_TWO_FILES_TO_ONE:
@@ -3296,7 +3296,7 @@ static int process_entry(struct merge_options *o,
 			 * can then be two-way merged cleanly, I guess it's
 			 * a clean merge?
 			 */
-			clean_merge = handle_rename_rename_2to1(o,
+			clean_merge = handle_rename_rename_2to1(opt,
 								conflict_info);
 			break;
 		default:
@@ -3306,18 +3306,18 @@ static int process_entry(struct merge_options *o,
 	} else if (o_oid && (!a_oid || !b_oid)) {
 		/* Case A: Deleted in one */
 		if ((!a_oid && !b_oid) ||
-		    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
-		    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
+		    (!b_oid && blob_unchanged(opt, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
+		    (!a_oid && blob_unchanged(opt, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_oid)
-				output(o, 2, _("Removing %s"), path);
+				output(opt, 2, _("Removing %s"), path);
 			/* do not touch working file if it did not exist */
-			remove_file(o, 1, path, !a_oid);
+			remove_file(opt, 1, path, !a_oid);
 		} else {
 			/* Modify/delete; deleted side may have put a directory in the way */
 			clean_merge = 0;
-			if (handle_modify_delete(o, path, o_oid, o_mode,
+			if (handle_modify_delete(opt, path, o_oid, o_mode,
 						 a_oid, a_mode, b_oid, b_mode))
 				clean_merge = -1;
 		}
@@ -3333,53 +3333,53 @@ static int process_entry(struct merge_options *o,
 		const char *conf;
 
 		if (a_oid) {
-			add_branch = o->branch1;
-			other_branch = o->branch2;
+			add_branch = opt->branch1;
+			other_branch = opt->branch2;
 			mode = a_mode;
 			oid = a_oid;
 			conf = _("file/directory");
 		} else {
-			add_branch = o->branch2;
-			other_branch = o->branch1;
+			add_branch = opt->branch2;
+			other_branch = opt->branch1;
 			mode = b_mode;
 			oid = b_oid;
 			conf = _("directory/file");
 		}
-		if (dir_in_way(o->repo->index, path,
-			       !o->call_depth && !S_ISGITLINK(a_mode),
+		if (dir_in_way(opt->repo->index, path,
+			       !opt->call_depth && !S_ISGITLINK(a_mode),
 			       0)) {
-			char *new_path = unique_path(o, path, add_branch);
+			char *new_path = unique_path(opt, path, add_branch);
 			clean_merge = 0;
-			output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
+			output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
 			       "Adding %s as %s"),
 			       conf, path, other_branch, path, new_path);
-			if (update_file(o, 0, oid, mode, new_path))
+			if (update_file(opt, 0, oid, mode, new_path))
 				clean_merge = -1;
-			else if (o->call_depth)
-				remove_file_from_index(o->repo->index, path);
+			else if (opt->call_depth)
+				remove_file_from_index(opt->repo->index, path);
 			free(new_path);
 		} else {
-			output(o, 2, _("Adding %s"), path);
+			output(opt, 2, _("Adding %s"), path);
 			/* do not overwrite file if already present */
-			if (update_file_flags(o, oid, mode, path, 1, !a_oid))
+			if (update_file_flags(opt, oid, mode, path, 1, !a_oid))
 				clean_merge = -1;
 		}
 	} else if (a_oid && b_oid) {
 		if (!o_oid) {
 			/* Case C: Added in both (check for same permissions) */
-			output(o, 1,
+			output(opt, 1,
 			       _("CONFLICT (add/add): Merge conflict in %s"),
 			       path);
-			clean_merge = handle_file_collision(o,
+			clean_merge = handle_file_collision(opt,
 							    path, NULL, NULL,
-							    o->branch1,
-							    o->branch2,
+							    opt->branch1,
+							    opt->branch2,
 							    a_oid, a_mode,
 							    b_oid, b_mode);
 		} else {
 			/* case D: Modified in both, but differently. */
 			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(o, path,
+			clean_merge = handle_content_merge(opt, path,
 							   is_dirty,
 							   o_oid, o_mode,
 							   a_oid, a_mode,
@@ -3391,48 +3391,48 @@ static int process_entry(struct merge_options *o,
 		 * this entry was deleted altogether. a_mode == 0 means
 		 * we had that path and want to actively remove it.
 		 */
-		remove_file(o, 1, path, !a_mode);
+		remove_file(opt, 1, path, !a_mode);
 	} else
 		BUG("fatal merge failure, shouldn't happen.");
 
 	return clean_merge;
 }
 
-int merge_trees(struct merge_options *o,
+int merge_trees(struct merge_options *opt,
 		struct tree *head,
 		struct tree *merge,
 		struct tree *common,
 		struct tree **result)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 	int code, clean;
 	struct strbuf sb = STRBUF_INIT;
 
-	if (!o->call_depth && repo_index_has_changes(o->repo, head, &sb)) {
-		err(o, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
+	if (!opt->call_depth && repo_index_has_changes(opt->repo, head, &sb)) {
+		err(opt, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
 		    sb.buf);
 		return -1;
 	}
 
-	if (o->subtree_shift) {
-		merge = shift_tree_object(o->repo, head, merge, o->subtree_shift);
-		common = shift_tree_object(o->repo, head, common, o->subtree_shift);
+	if (opt->subtree_shift) {
+		merge = shift_tree_object(opt->repo, head, merge, opt->subtree_shift);
+		common = shift_tree_object(opt->repo, head, common, opt->subtree_shift);
 	}
 
 	if (oid_eq(&common->object.oid, &merge->object.oid)) {
-		output(o, 0, _("Already up to date!"));
+		output(opt, 0, _("Already up to date!"));
 		*result = head;
 		return 1;
 	}
 
-	code = unpack_trees_start(o, common, head, merge);
+	code = unpack_trees_start(opt, common, head, merge);
 
 	if (code != 0) {
-		if (show(o, 4) || o->call_depth)
-			err(o, _("merging of trees %s and %s failed"),
+		if (show(opt, 4) || opt->call_depth)
+			err(opt, _("merging of trees %s and %s failed"),
 			    oid_to_hex(&head->object.oid),
 			    oid_to_hex(&merge->object.oid));
-		unpack_trees_finish(o);
+		unpack_trees_finish(opt);
 		return -1;
 	}
 
@@ -3447,21 +3447,21 @@ int merge_trees(struct merge_options *o,
 		 * opposed to decaring a local hashmap is for convenience
 		 * so that we don't have to pass it to around.
 		 */
-		hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
-		get_files_dirs(o, head);
-		get_files_dirs(o, merge);
+		hashmap_init(&opt->current_file_dir_set, path_hashmap_cmp, NULL, 512);
+		get_files_dirs(opt, head);
+		get_files_dirs(opt, merge);
 
-		entries = get_unmerged(o->repo->index);
-		clean = detect_and_process_renames(o, common, head, merge,
+		entries = get_unmerged(opt->repo->index);
+		clean = detect_and_process_renames(opt, common, head, merge,
 						   entries, &re_info);
-		record_df_conflict_files(o, entries);
+		record_df_conflict_files(opt, entries);
 		if (clean < 0)
 			goto cleanup;
 		for (i = entries->nr-1; 0 <= i; i--) {
 			const char *path = entries->items[i].string;
 			struct stage_data *e = entries->items[i].util;
 			if (!e->processed) {
-				int ret = process_entry(o, path, e);
+				int ret = process_entry(opt, path, e);
 				if (!ret)
 					clean = 0;
 				else if (ret < 0) {
@@ -3483,19 +3483,19 @@ int merge_trees(struct merge_options *o,
 		string_list_clear(entries, 1);
 		free(entries);
 
-		hashmap_free(&o->current_file_dir_set, 1);
+		hashmap_free(&opt->current_file_dir_set, 1);
 
 		if (clean < 0) {
-			unpack_trees_finish(o);
+			unpack_trees_finish(opt);
 			return clean;
 		}
 	}
 	else
 		clean = 1;
 
-	unpack_trees_finish(o);
+	unpack_trees_finish(opt);
 
-	if (o->call_depth && !(*result = write_tree_from_memory(o)))
+	if (opt->call_depth && !(*result = write_tree_from_memory(opt)))
 		return -1;
 
 	return clean;
@@ -3516,7 +3516,7 @@ static struct commit_list *reverse_commit_list(struct commit_list *list)
  * Merge the commits h1 and h2, return the resulting virtual
  * commit object and a flag indicating the cleanness of the merge.
  */
-int merge_recursive(struct merge_options *o,
+int merge_recursive(struct merge_options *opt,
 		    struct commit *h1,
 		    struct commit *h2,
 		    struct commit_list *ca,
@@ -3527,10 +3527,10 @@ int merge_recursive(struct merge_options *o,
 	struct tree *mrtree;
 	int clean;
 
-	if (show(o, 4)) {
-		output(o, 4, _("Merging:"));
-		output_commit_title(o, h1);
-		output_commit_title(o, h2);
+	if (show(opt, 4)) {
+		output(opt, 4, _("Merging:"));
+		output_commit_title(opt, h1);
+		output_commit_title(opt, h2);
 	}
 
 	if (!ca) {
@@ -3538,13 +3538,13 @@ int merge_recursive(struct merge_options *o,
 		ca = reverse_commit_list(ca);
 	}
 
-	if (show(o, 5)) {
+	if (show(opt, 5)) {
 		unsigned cnt = commit_list_count(ca);
 
-		output(o, 5, Q_("found %u common ancestor:",
+		output(opt, 5, Q_("found %u common ancestor:",
 				"found %u common ancestors:", cnt), cnt);
 		for (iter = ca; iter; iter = iter->next)
-			output_commit_title(o, iter->item);
+			output_commit_title(opt, iter->item);
 	}
 
 	merged_common_ancestors = pop_commit(&ca);
@@ -3552,13 +3552,13 @@ int merge_recursive(struct merge_options *o,
 		/* if there is no common ancestor, use an empty tree */
 		struct tree *tree;
 
-		tree = lookup_tree(o->repo, o->repo->hash_algo->empty_tree);
-		merged_common_ancestors = make_virtual_commit(o->repo, tree, "ancestor");
+		tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree);
+		merged_common_ancestors = make_virtual_commit(opt->repo, tree, "ancestor");
 	}
 
 	for (iter = ca; iter; iter = iter->next) {
 		const char *saved_b1, *saved_b2;
-		o->call_depth++;
+		opt->call_depth++;
 		/*
 		 * When the merge fails, the result contains files
 		 * with conflict markers. The cleanness flag is
@@ -3567,46 +3567,46 @@ int merge_recursive(struct merge_options *o,
 		 * overwritten it: the committed "conflicts" were
 		 * already resolved.
 		 */
-		discard_index(o->repo->index);
-		saved_b1 = o->branch1;
-		saved_b2 = o->branch2;
-		o->branch1 = "Temporary merge branch 1";
-		o->branch2 = "Temporary merge branch 2";
-		if (merge_recursive(o, merged_common_ancestors, iter->item,
+		discard_index(opt->repo->index);
+		saved_b1 = opt->branch1;
+		saved_b2 = opt->branch2;
+		opt->branch1 = "Temporary merge branch 1";
+		opt->branch2 = "Temporary merge branch 2";
+		if (merge_recursive(opt, merged_common_ancestors, iter->item,
 				    NULL, &merged_common_ancestors) < 0)
 			return -1;
-		o->branch1 = saved_b1;
-		o->branch2 = saved_b2;
-		o->call_depth--;
+		opt->branch1 = saved_b1;
+		opt->branch2 = saved_b2;
+		opt->call_depth--;
 
 		if (!merged_common_ancestors)
-			return err(o, _("merge returned no commit"));
+			return err(opt, _("merge returned no commit"));
 	}
 
-	discard_index(o->repo->index);
-	if (!o->call_depth)
-		repo_read_index(o->repo);
+	discard_index(opt->repo->index);
+	if (!opt->call_depth)
+		repo_read_index(opt->repo);
 
-	o->ancestor = "merged common ancestors";
-	clean = merge_trees(o, get_commit_tree(h1), get_commit_tree(h2),
+	opt->ancestor = "merged common ancestors";
+	clean = merge_trees(opt, get_commit_tree(h1), get_commit_tree(h2),
 			    get_commit_tree(merged_common_ancestors),
 			    &mrtree);
 	if (clean < 0) {
-		flush_output(o);
+		flush_output(opt);
 		return clean;
 	}
 
-	if (o->call_depth) {
-		*result = make_virtual_commit(o->repo, mrtree, "merged tree");
+	if (opt->call_depth) {
+		*result = make_virtual_commit(opt->repo, mrtree, "merged tree");
 		commit_list_insert(h1, &(*result)->parents);
 		commit_list_insert(h2, &(*result)->parents->next);
 	}
-	flush_output(o);
-	if (!o->call_depth && o->buffer_output < 2)
-		strbuf_release(&o->obuf);
-	if (show(o, 2))
+	flush_output(opt);
+	if (!opt->call_depth && opt->buffer_output < 2)
+		strbuf_release(&opt->obuf);
+	if (show(opt, 2))
 		diff_warn_rename_limit("merge.renamelimit",
-				       o->needed_rename_limit, 0);
+				       opt->needed_rename_limit, 0);
 	return clean;
 }
 
@@ -3628,7 +3628,7 @@ static struct commit *get_ref(struct repository *repo, const struct object_id *o
 	return (struct commit *)object;
 }
 
-int merge_recursive_generic(struct merge_options *o,
+int merge_recursive_generic(struct merge_options *opt,
 			    const struct object_id *head,
 			    const struct object_id *merge,
 			    int num_base_list,
@@ -3637,127 +3637,127 @@ int merge_recursive_generic(struct merge_options *o,
 {
 	int clean;
 	struct lock_file lock = LOCK_INIT;
-	struct commit *head_commit = get_ref(o->repo, head, o->branch1);
-	struct commit *next_commit = get_ref(o->repo, merge, o->branch2);
+	struct commit *head_commit = get_ref(opt->repo, head, opt->branch1);
+	struct commit *next_commit = get_ref(opt->repo, merge, opt->branch2);
 	struct commit_list *ca = NULL;
 
 	if (base_list) {
 		int i;
 		for (i = 0; i < num_base_list; ++i) {
 			struct commit *base;
-			if (!(base = get_ref(o->repo, base_list[i], oid_to_hex(base_list[i]))))
-				return err(o, _("Could not parse object '%s'"),
+			if (!(base = get_ref(opt->repo, base_list[i], oid_to_hex(base_list[i]))))
+				return err(opt, _("Could not parse object '%s'"),
 					   oid_to_hex(base_list[i]));
 			commit_list_insert(base, &ca);
 		}
 	}
 
-	repo_hold_locked_index(o->repo, &lock, LOCK_DIE_ON_ERROR);
-	clean = merge_recursive(o, head_commit, next_commit, ca,
+	repo_hold_locked_index(opt->repo, &lock, LOCK_DIE_ON_ERROR);
+	clean = merge_recursive(opt, head_commit, next_commit, ca,
 				result);
 	if (clean < 0) {
 		rollback_lock_file(&lock);
 		return clean;
 	}
 
-	if (write_locked_index(o->repo->index, &lock,
+	if (write_locked_index(opt->repo->index, &lock,
 			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
-		return err(o, _("Unable to write index."));
+		return err(opt, _("Unable to write index."));
 
 	return clean ? 0 : 1;
 }
 
-static void merge_recursive_config(struct merge_options *o)
+static void merge_recursive_config(struct merge_options *opt)
 {
 	char *value = NULL;
-	git_config_get_int("merge.verbosity", &o->verbosity);
-	git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
-	git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
+	git_config_get_int("merge.verbosity", &opt->verbosity);
+	git_config_get_int("diff.renamelimit", &opt->diff_rename_limit);
+	git_config_get_int("merge.renamelimit", &opt->merge_rename_limit);
 	if (!git_config_get_string("diff.renames", &value)) {
-		o->diff_detect_rename = git_config_rename("diff.renames", value);
+		opt->diff_detect_rename = git_config_rename("diff.renames", value);
 		free(value);
 	}
 	if (!git_config_get_string("merge.renames", &value)) {
-		o->merge_detect_rename = git_config_rename("merge.renames", value);
+		opt->merge_detect_rename = git_config_rename("merge.renames", value);
 		free(value);
 	}
 	git_config(git_xmerge_config, NULL);
 }
 
-void init_merge_options(struct merge_options *o,
+void init_merge_options(struct merge_options *opt,
 			struct repository *repo)
 {
 	const char *merge_verbosity;
-	memset(o, 0, sizeof(struct merge_options));
-	o->repo = repo;
-	o->verbosity = 2;
-	o->buffer_output = 1;
-	o->diff_rename_limit = -1;
-	o->merge_rename_limit = -1;
-	o->renormalize = 0;
-	o->diff_detect_rename = -1;
-	o->merge_detect_rename = -1;
-	o->detect_directory_renames = 1;
-	merge_recursive_config(o);
+	memset(opt, 0, sizeof(struct merge_options));
+	opt->repo = repo;
+	opt->verbosity = 2;
+	opt->buffer_output = 1;
+	opt->diff_rename_limit = -1;
+	opt->merge_rename_limit = -1;
+	opt->renormalize = 0;
+	opt->diff_detect_rename = -1;
+	opt->merge_detect_rename = -1;
+	opt->detect_directory_renames = 1;
+	merge_recursive_config(opt);
 	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
 	if (merge_verbosity)
-		o->verbosity = strtol(merge_verbosity, NULL, 10);
-	if (o->verbosity >= 5)
-		o->buffer_output = 0;
-	strbuf_init(&o->obuf, 0);
-	string_list_init(&o->df_conflict_file_set, 1);
+		opt->verbosity = strtol(merge_verbosity, NULL, 10);
+	if (opt->verbosity >= 5)
+		opt->buffer_output = 0;
+	strbuf_init(&opt->obuf, 0);
+	string_list_init(&opt->df_conflict_file_set, 1);
 }
 
-int parse_merge_opt(struct merge_options *o, const char *s)
+int parse_merge_opt(struct merge_options *opt, const char *s)
 {
 	const char *arg;
 
 	if (!s || !*s)
 		return -1;
 	if (!strcmp(s, "ours"))
-		o->recursive_variant = MERGE_RECURSIVE_OURS;
+		opt->recursive_variant = MERGE_RECURSIVE_OURS;
 	else if (!strcmp(s, "theirs"))
-		o->recursive_variant = MERGE_RECURSIVE_THEIRS;
+		opt->recursive_variant = MERGE_RECURSIVE_THEIRS;
 	else if (!strcmp(s, "subtree"))
-		o->subtree_shift = "";
+		opt->subtree_shift = "";
 	else if (skip_prefix(s, "subtree=", &arg))
-		o->subtree_shift = arg;
+		opt->subtree_shift = arg;
 	else if (!strcmp(s, "patience"))
-		o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
+		opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
 	else if (!strcmp(s, "histogram"))
-		o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
+		opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
 	else if (skip_prefix(s, "diff-algorithm=", &arg)) {
 		long value = parse_algorithm_value(arg);
 		if (value < 0)
 			return -1;
 		/* clear out previous settings */
-		DIFF_XDL_CLR(o, NEED_MINIMAL);
-		o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
-		o->xdl_opts |= value;
+		DIFF_XDL_CLR(opt, NEED_MINIMAL);
+		opt->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
+		opt->xdl_opts |= value;
 	}
 	else if (!strcmp(s, "ignore-space-change"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE_CHANGE);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
 	else if (!strcmp(s, "ignore-all-space"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
 	else if (!strcmp(s, "ignore-space-at-eol"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
 	else if (!strcmp(s, "ignore-cr-at-eol"))
-		DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
+		DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
 	else if (!strcmp(s, "renormalize"))
-		o->renormalize = 1;
+		opt->renormalize = 1;
 	else if (!strcmp(s, "no-renormalize"))
-		o->renormalize = 0;
+		opt->renormalize = 0;
 	else if (!strcmp(s, "no-renames"))
-		o->merge_detect_rename = 0;
+		opt->merge_detect_rename = 0;
 	else if (!strcmp(s, "find-renames")) {
-		o->merge_detect_rename = 1;
-		o->rename_score = 0;
+		opt->merge_detect_rename = 1;
+		opt->rename_score = 0;
 	}
 	else if (skip_prefix(s, "find-renames=", &arg) ||
 		 skip_prefix(s, "rename-threshold=", &arg)) {
-		if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
+		if ((opt->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
 			return -1;
-		o->merge_detect_rename = 1;
+		opt->merge_detect_rename = 1;
 	}
 	/*
 	 * Please update $__git_merge_strategy_options in
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 03/15] merge-recursive: rename diff_filespec 'one' to 'o'

[Elijah Newren]

In the previous commit, we noted that several places throughout merge
recursive both had a reason to use 'o'; some for a merge_options struct,
and others for a diff_filespec struct.  Some places had both, forcing
one of the two to be renamed, though the choice was inconsistent.  Now
that the merge_options struct has been renamed to 'opt' everywhere, we
can replace the few places that used 'one' for the diff_filespec to 'o'.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 09b76d596e..36af5d9cc6 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1050,7 +1050,7 @@ struct merge_file_info {
 
 static int merge_3way(struct merge_options *opt,
 		      mmbuffer_t *result_buf,
-		      const struct diff_filespec *one,
+		      const struct diff_filespec *o,
 		      const struct diff_filespec *a,
 		      const struct diff_filespec *b,
 		      const char *branch1,
@@ -1084,9 +1084,9 @@ static int merge_3way(struct merge_options *opt,
 	}
 
 	if (strcmp(a->path, b->path) ||
-	    (opt->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
+	    (opt->ancestor != NULL && strcmp(a->path, o->path) != 0)) {
 		base_name = opt->ancestor == NULL ? NULL :
-			mkpathdup("%s:%s", opt->ancestor, one->path);
+			mkpathdup("%s:%s", opt->ancestor, o->path);
 		name1 = mkpathdup("%s:%s", branch1, a->path);
 		name2 = mkpathdup("%s:%s", branch2, b->path);
 	} else {
@@ -1096,7 +1096,7 @@ static int merge_3way(struct merge_options *opt,
 		name2 = mkpathdup("%s", branch2);
 	}
 
-	read_mmblob(&orig, &one->oid);
+	read_mmblob(&orig, &o->oid);
 	read_mmblob(&src1, &a->oid);
 	read_mmblob(&src2, &b->oid);
 
@@ -1295,7 +1295,7 @@ static int merge_submodule(struct merge_options *opt,
 }
 
 static int merge_mode_and_contents(struct merge_options *opt,
-				   const struct diff_filespec *one,
+				   const struct diff_filespec *o,
 				   const struct diff_filespec *a,
 				   const struct diff_filespec *b,
 				   const char *filename,
@@ -1310,7 +1310,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		 * side of the conflict markers and the other branch on the
 		 * top.  Fix that.
 		 */
-		return merge_mode_and_contents(opt, one, b, a,
+		return merge_mode_and_contents(opt, o, b, a,
 					       filename,
 					       branch2, branch1,
 					       extra_marker_size, result);
@@ -1329,31 +1329,31 @@ static int merge_mode_and_contents(struct merge_options *opt,
 			oidcpy(&result->oid, &b->oid);
 		}
 	} else {
-		if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
+		if (!oid_eq(&a->oid, &o->oid) && !oid_eq(&b->oid, &o->oid))
 			result->merge = 1;
 
 		/*
 		 * Merge modes
 		 */
-		if (a->mode == b->mode || a->mode == one->mode)
+		if (a->mode == b->mode || a->mode == o->mode)
 			result->mode = b->mode;
 		else {
 			result->mode = a->mode;
-			if (b->mode != one->mode) {
+			if (b->mode != o->mode) {
 				result->clean = 0;
 				result->merge = 1;
 			}
 		}
 
-		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
+		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &o->oid))
 			oidcpy(&result->oid, &b->oid);
-		else if (oid_eq(&b->oid, &one->oid))
+		else if (oid_eq(&b->oid, &o->oid))
 			oidcpy(&result->oid, &a->oid);
 		else if (S_ISREG(a->mode)) {
 			mmbuffer_t result_buf;
 			int ret = 0, merge_status;
 
-			merge_status = merge_3way(opt, &result_buf, one, a, b,
+			merge_status = merge_3way(opt, &result_buf, o, a, b,
 						  branch1, branch2,
 						  extra_marker_size);
 
@@ -1372,8 +1372,8 @@ static int merge_mode_and_contents(struct merge_options *opt,
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
 			result->clean = merge_submodule(opt, &result->oid,
-							one->path,
-							&one->oid,
+							o->path,
+							&o->oid,
 							&a->oid,
 							&b->oid);
 		} else if (S_ISLNK(a->mode)) {
@@ -1750,7 +1750,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	struct merge_file_info mfi;
 	struct diff_filespec other;
 	struct diff_filespec *add;
-	struct diff_filespec *one = ci->pair1->one;
+	struct diff_filespec *o = ci->pair1->one;
 	struct diff_filespec *a = ci->pair1->two;
 	struct diff_filespec *b = ci->pair2->two;
 	char *path_desc;
@@ -1758,13 +1758,13 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
-	       one->path, a->path, ci->branch1,
-	       one->path, b->path, ci->branch2,
+	       o->path, a->path, ci->branch1,
+	       o->path, b->path, ci->branch2,
 	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
-			    a->path, b->path, one->path);
-	if (merge_mode_and_contents(opt, one, a, b, path_desc,
+			    a->path, b->path, o->path);
+	if (merge_mode_and_contents(opt, o, a, b, path_desc,
 				    ci->branch1, ci->branch2,
 				    opt->call_depth * 2, &mfi))
 		return -1;
@@ -1777,7 +1777,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(opt, 0, &mfi.oid, mfi.mode, one->path))
+		if (update_file(opt, 0, &mfi.oid, mfi.mode, o->path))
 			return -1;
 
 		/*
@@ -2863,10 +2863,10 @@ static int process_renames(struct merge_options *opt,
 			if (clean_merge < 0)
 				goto cleanup_and_return;
 			if (try_merge) {
-				struct diff_filespec *one, *a, *b;
+				struct diff_filespec *o, *a, *b;
 				src_other.path = (char *)ren1_src;
 
-				one = ren1->pair->one;
+				o = ren1->pair->one;
 				if (a_renames == renames1) {
 					a = ren1->pair->two;
 					b = &src_other;
@@ -2874,7 +2874,7 @@ static int process_renames(struct merge_options *opt,
 					b = ren1->pair->two;
 					a = &src_other;
 				}
-				update_entry(ren1->dst_entry, one, a, b);
+				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
 							   ren1->pair,
 							   NULL,
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 04/15] merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'

[Elijah Newren]

Since we want to replace oid,mode pairs with a single diff_filespec,
we will soon want to be able to use the names 'o', 'a', and 'b' for
the three different file versions.  Rename some local variables in
blob_unchanged() that would otherwise conflict.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 36af5d9cc6..4ed1b48630 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3031,9 +3031,10 @@ static int blob_unchanged(struct merge_options *opt,
 			  unsigned a_mode,
 			  int renormalize, const char *path)
 {
-	struct strbuf o = STRBUF_INIT;
-	struct strbuf a = STRBUF_INIT;
+	struct strbuf obuf = STRBUF_INIT;
+	struct strbuf abuf = STRBUF_INIT;
 	int ret = 0; /* assume changed for safety */
+	const struct index_state *idx = opt->repo->index;
 
 	if (a_mode != o_mode)
 		return 0;
@@ -3043,20 +3044,21 @@ static int blob_unchanged(struct merge_options *opt,
 		return 0;
 
 	assert(o_oid && a_oid);
-	if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
+	if (read_oid_strbuf(opt, o_oid, &obuf) ||
+	    read_oid_strbuf(opt, a_oid, &abuf))
 		goto error_return;
 	/*
 	 * Note: binary | is used so that both renormalizations are
 	 * performed.  Comparison can be skipped if both files are
 	 * unchanged since their sha1s have already been compared.
 	 */
-	if (renormalize_buffer(opt->repo->index, path, o.buf, o.len, &o) |
-	    renormalize_buffer(opt->repo->index, path, a.buf, a.len, &a))
-		ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+	if (renormalize_buffer(idx, path, obuf.buf, obuf.len, &obuf) |
+	    renormalize_buffer(idx, path, abuf.buf, abuf.len, &abuf))
+		ret = (obuf.len == abuf.len && !memcmp(obuf.buf, abuf.buf, obuf.len));
 
 error_return:
-	strbuf_release(&o);
-	strbuf_release(&a);
+	strbuf_release(&obuf);
+	strbuf_release(&abuf);
 	return ret;
 }
 
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 05/15] merge-recursive: use 'ci' for rename_conflict_info variable name

[Elijah Newren]

We used a couple different names, but used 'ci' the most.  Use the same
variable name throughout for a little extra consistency.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 4ed1b48630..ea5646debd 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3098,7 +3098,7 @@ static int handle_content_merge(struct merge_options *opt,
 				struct object_id *o_oid, int o_mode,
 				struct object_id *a_oid, int a_mode,
 				struct object_id *b_oid, int b_mode,
-				struct rename_conflict_info *rename_conflict_info)
+				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
 	const char *path1 = NULL, *path2 = NULL;
@@ -3118,17 +3118,17 @@ static int handle_content_merge(struct merge_options *opt,
 	oidcpy(&b.oid, b_oid);
 	b.mode = b_mode;
 
-	if (rename_conflict_info) {
-		struct diff_filepair *pair1 = rename_conflict_info->pair1;
+	if (ci) {
+		struct diff_filepair *pair1 = ci->pair1;
 
-		path1 = (opt->branch1 == rename_conflict_info->branch1) ?
+		path1 = (opt->branch1 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
-		/* If rename_conflict_info->pair2 != NULL, we are in
+		/* If ci->pair2 != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
-		path2 = (rename_conflict_info->pair2 ||
-			 opt->branch2 == rename_conflict_info->branch1) ?
+		path2 = (ci->pair2 ||
+			 opt->branch2 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
 		a.path = (char *)path1;
@@ -3180,7 +3180,7 @@ static int handle_content_merge(struct merge_options *opt,
 			reason = _("submodule");
 		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
-		if (rename_conflict_info && !df_conflict_remains)
+		if (ci && !df_conflict_remains)
 			if (update_stages(opt, path, &one, &a, &b))
 				return -1;
 	}
@@ -3206,7 +3206,7 @@ static int handle_content_merge(struct merge_options *opt,
 			}
 
 		}
-		new_path = unique_path(opt, path, rename_conflict_info->branch1);
+		new_path = unique_path(opt, path, ci->branch1);
 		if (is_dirty) {
 			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
@@ -3251,8 +3251,8 @@ static int process_entry(struct merge_options *opt,
 
 	entry->processed = 1;
 	if (entry->rename_conflict_info) {
-		struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
-		switch (conflict_info->rename_type) {
+		struct rename_conflict_info *ci = entry->rename_conflict_info;
+		switch (ci->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
 			clean_merge = handle_rename_normal(opt,
@@ -3260,13 +3260,11 @@ static int process_entry(struct merge_options *opt,
 							   o_oid, o_mode,
 							   a_oid, a_mode,
 							   b_oid, b_mode,
-							   conflict_info);
+							   ci);
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt,
-						  conflict_info->pair1,
-						  conflict_info->branch1))
+			if (handle_rename_via_dir(opt, ci->pair1, ci->branch1))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3276,19 +3274,17 @@ static int process_entry(struct merge_options *opt,
 			 * two-way merged cleanly with the added file, I
 			 * guess it's a clean merge?
 			 */
-			clean_merge = handle_rename_add(opt, conflict_info);
+			clean_merge = handle_rename_add(opt, ci);
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(opt,
-						 conflict_info->pair1,
-						 conflict_info->branch1,
-						 conflict_info->branch2))
+			if (handle_rename_delete(opt, ci->pair1,
+						 ci->branch1, ci->branch2))
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
 			clean_merge = 0;
-			if (handle_rename_rename_1to2(opt, conflict_info))
+			if (handle_rename_rename_1to2(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_TWO_FILES_TO_ONE:
@@ -3298,8 +3294,7 @@ static int process_entry(struct merge_options *opt,
 			 * can then be two-way merged cleanly, I guess it's
 			 * a clean merge?
 			 */
-			clean_merge = handle_rename_rename_2to1(opt,
-								conflict_info);
+			clean_merge = handle_rename_rename_2to1(opt, ci);
 			break;
 		default:
 			entry->processed = 0;
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 06/15] merge-recursive: move some struct declarations together

[Elijah Newren]

These structs are related and reference each other, so move them
together to make it easier for folks to determine what they hold and
what their purpose is.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 78 +++++++++++++++++++++++------------------------
 1 file changed, 39 insertions(+), 39 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index ea5646debd..c4a2ef2a37 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -196,18 +196,6 @@ enum rename_type {
 	RENAME_TWO_FILES_TO_ONE
 };
 
-struct rename_conflict_info {
-	enum rename_type rename_type;
-	struct diff_filepair *pair1;
-	struct diff_filepair *pair2;
-	const char *branch1;
-	const char *branch2;
-	struct stage_data *dst_entry1;
-	struct stage_data *dst_entry2;
-	struct diff_filespec ren1_other;
-	struct diff_filespec ren2_other;
-};
-
 /*
  * Since we want to write the index eventually, we cannot reuse the index
  * for these (temporary) data.
@@ -221,6 +209,45 @@ struct stage_data {
 	unsigned processed:1;
 };
 
+struct rename {
+	struct diff_filepair *pair;
+	/*
+	 * Purpose of src_entry and dst_entry:
+	 *
+	 * If 'before' is renamed to 'after' then src_entry will contain
+	 * the versions of 'before' from the merge_base, HEAD, and MERGE in
+	 * stages 1, 2, and 3; dst_entry will contain the respective
+	 * versions of 'after' in corresponding locations.  Thus, we have a
+	 * total of six modes and oids, though some will be null.  (Stage 0
+	 * is ignored; we're interested in handling conflicts.)
+	 *
+	 * Since we don't turn on break-rewrites by default, neither
+	 * src_entry nor dst_entry can have all three of their stages have
+	 * non-null oids, meaning at most four of the six will be non-null.
+	 * Also, since this is a rename, both src_entry and dst_entry will
+	 * have at least one non-null oid, meaning at least two will be
+	 * non-null.  Of the six oids, a typical rename will have three be
+	 * non-null.  Only two implies a rename/delete, and four implies a
+	 * rename/add.
+	 */
+	struct stage_data *src_entry;
+	struct stage_data *dst_entry;
+	unsigned add_turned_into_rename:1;
+	unsigned processed:1;
+};
+
+struct rename_conflict_info {
+	enum rename_type rename_type;
+	struct diff_filepair *pair1;
+	struct diff_filepair *pair2;
+	const char *branch1;
+	const char *branch2;
+	struct stage_data *dst_entry1;
+	struct stage_data *dst_entry2;
+	struct diff_filespec ren1_other;
+	struct diff_filespec ren2_other;
+};
+
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      struct diff_filepair *pair1,
 					      struct diff_filepair *pair2,
@@ -645,33 +672,6 @@ static void record_df_conflict_files(struct merge_options *opt,
 	string_list_clear(&df_sorted_entries, 0);
 }
 
-struct rename {
-	struct diff_filepair *pair;
-	/*
-	 * Purpose of src_entry and dst_entry:
-	 *
-	 * If 'before' is renamed to 'after' then src_entry will contain
-	 * the versions of 'before' from the merge_base, HEAD, and MERGE in
-	 * stages 1, 2, and 3; dst_entry will contain the respective
-	 * versions of 'after' in corresponding locations.  Thus, we have a
-	 * total of six modes and oids, though some will be null.  (Stage 0
-	 * is ignored; we're interested in handling conflicts.)
-	 *
-	 * Since we don't turn on break-rewrites by default, neither
-	 * src_entry nor dst_entry can have all three of their stages have
-	 * non-null oids, meaning at most four of the six will be non-null.
-	 * Also, since this is a rename, both src_entry and dst_entry will
-	 * have at least one non-null oid, meaning at least two will be
-	 * non-null.  Of the six oids, a typical rename will have three be
-	 * non-null.  Only two implies a rename/delete, and four implies a
-	 * rename/add.
-	 */
-	struct stage_data *src_entry;
-	struct stage_data *dst_entry;
-	unsigned add_turned_into_rename:1;
-	unsigned processed:1;
-};
-
 static int update_stages(struct merge_options *opt, const char *path,
 			 const struct diff_filespec *o,
 			 const struct diff_filespec *a,
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 07/15] merge-recursive: shrink rename_conflict_info

[Elijah Newren]

The rename_conflict_info struct used both a pair and a stage_data which
were taken from a rename struct.  Just use the original rename struct.
This will also allow us to start making other simplifications to the
code.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 120 +++++++++++++++++++---------------------------
 1 file changed, 50 insertions(+), 70 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index c4a2ef2a37..e05f8f22f5 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -238,24 +238,20 @@ struct rename {
 
 struct rename_conflict_info {
 	enum rename_type rename_type;
-	struct diff_filepair *pair1;
-	struct diff_filepair *pair2;
+	struct rename *ren1;
+	struct rename *ren2;
 	const char *branch1;
 	const char *branch2;
-	struct stage_data *dst_entry1;
-	struct stage_data *dst_entry2;
 	struct diff_filespec ren1_other;
 	struct diff_filespec ren2_other;
 };
 
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
-					      struct diff_filepair *pair1,
-					      struct diff_filepair *pair2,
+					      struct merge_options *opt,
+					      struct rename *ren1,
+					      struct rename *ren2,
 					      const char *branch1,
 					      const char *branch2,
-					      struct stage_data *dst_entry1,
-					      struct stage_data *dst_entry2,
-					      struct merge_options *opt,
 					      struct stage_data *src_entry1,
 					      struct stage_data *src_entry2)
 {
@@ -269,31 +265,27 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (dst_entry2 && branch1 != opt->branch1) {
+	if (ren2 && branch1 != opt->branch1) {
 		setup_rename_conflict_info(rename_type,
-					   pair2,      pair1,
-					   branch2,    branch1,
-					   dst_entry2, dst_entry1,
 					   opt,
+					   ren2,       ren1,
+					   branch2,    branch1,
 					   src_entry2, src_entry1);
 		return;
 	}
 
 	ci = xcalloc(1, sizeof(struct rename_conflict_info));
 	ci->rename_type = rename_type;
-	ci->pair1 = pair1;
+	ci->ren1 = ren1;
+	ci->ren2 = ren2;
 	ci->branch1 = branch1;
 	ci->branch2 = branch2;
 
-	ci->dst_entry1 = dst_entry1;
-	dst_entry1->rename_conflict_info = ci;
-	dst_entry1->processed = 0;
+	ci->ren1->dst_entry->processed = 0;
+	ci->ren1->dst_entry->rename_conflict_info = ci;
 
-	assert(!pair2 == !dst_entry2);
-	if (dst_entry2) {
-		ci->dst_entry2 = dst_entry2;
-		ci->pair2 = pair2;
-		dst_entry2->rename_conflict_info = ci;
+	if (ren2) {
+		ci->ren2->dst_entry->rename_conflict_info = ci;
 	}
 
 	/*
@@ -305,7 +297,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	    rename_type == RENAME_TWO_FILES_TO_ONE) {
 		ostage1 = opt->branch1 == branch1 ? 3 : 2;
 
-		ci->ren1_other.path = pair1->one->path;
+		ci->ren1_other.path = ren1->pair->one->path;
 		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
 		ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 	}
@@ -313,7 +305,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 		ostage2 = ostage1 ^ 1;
 
-		ci->ren2_other.path = pair2->one->path;
+		ci->ren2_other.path = ren2->pair->one->path;
 		oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
 		ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 	}
@@ -1694,8 +1686,8 @@ static int handle_rename_add(struct merge_options *opt,
 			     struct rename_conflict_info *ci)
 {
 	/* a was renamed to c, and a separate c was added. */
-	struct diff_filespec *a = ci->pair1->one;
-	struct diff_filespec *c = ci->pair1->two;
+	struct diff_filespec *a = ci->ren1->pair->one;
+	struct diff_filespec *c = ci->ren1->pair->two;
 	char *path = c->path;
 	char *prev_path_desc;
 	struct merge_file_info mfi;
@@ -1718,8 +1710,8 @@ static int handle_rename_add(struct merge_options *opt,
 				     c->path, a->path, NULL,
 				     ci->branch1, ci->branch2,
 				     &mfi.oid, mfi.mode,
-				     &ci->dst_entry1->stages[other_stage].oid,
-				     ci->dst_entry1->stages[other_stage].mode);
+				     &ci->ren1->dst_entry->stages[other_stage].oid,
+				     ci->ren1->dst_entry->stages[other_stage].mode);
 }
 
 static char *find_path_for_conflict(struct merge_options *opt,
@@ -1750,9 +1742,9 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	struct merge_file_info mfi;
 	struct diff_filespec other;
 	struct diff_filespec *add;
-	struct diff_filespec *o = ci->pair1->one;
-	struct diff_filespec *a = ci->pair1->two;
-	struct diff_filespec *b = ci->pair2->two;
+	struct diff_filespec *o = ci->ren1->pair->one;
+	struct diff_filespec *a = ci->ren1->pair->two;
+	struct diff_filespec *b = ci->ren2->pair->two;
 	char *path_desc;
 
 	output(opt, 1, _("CONFLICT (rename/rename): "
@@ -1788,14 +1780,14 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * such cases, we should keep the added file around,
 		 * resolving the conflict at that path in its favor.
 		 */
-		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
+		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
 		if (add) {
 			if (update_file(opt, 0, &add->oid, add->mode, a->path))
 				return -1;
 		}
 		else
 			remove_file_from_index(opt->repo->index, a->path);
-		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
+		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
 		if (add) {
 			if (update_file(opt, 0, &add->oid, add->mode, b->path))
 				return -1;
@@ -1808,7 +1800,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * rename/add collision.  If not, we can write the file out
 		 * to the specified location.
 		 */
-		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
+		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
 		if (add) {
 			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
@@ -1827,7 +1819,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 				return -1;
 		}
 
-		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
+		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
 		if (add) {
 			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
@@ -1854,10 +1846,10 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
 	/* Two files, a & b, were renamed to the same thing, c. */
-	struct diff_filespec *a = ci->pair1->one;
-	struct diff_filespec *b = ci->pair2->one;
-	struct diff_filespec *c1 = ci->pair1->two;
-	struct diff_filespec *c2 = ci->pair2->two;
+	struct diff_filespec *a = ci->ren1->pair->one;
+	struct diff_filespec *b = ci->ren2->pair->one;
+	struct diff_filespec *c1 = ci->ren1->pair->two;
+	struct diff_filespec *c2 = ci->ren2->pair->two;
 	char *path = c1->path; /* == c2->path */
 	char *path_side_1_desc;
 	char *path_side_2_desc;
@@ -2732,13 +2724,11 @@ static int process_renames(struct merge_options *opt,
 					     ren2->pair->two);
 			}
 			setup_rename_conflict_info(rename_type,
-						   ren1->pair,
-						   ren2->pair,
+						   opt,
+						   ren1,
+						   ren2,
 						   branch1,
 						   branch2,
-						   ren1->dst_entry,
-						   ren2->dst_entry,
-						   opt,
 						   NULL,
 						   NULL);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
@@ -2759,13 +2749,11 @@ static int process_renames(struct merge_options *opt,
 			ren2->src_entry->processed = 1;
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
-						   ren1->pair,
-						   ren2->pair,
+						   opt,
+						   ren1,
+						   ren2,
 						   branch1,
 						   branch2,
-						   ren1->dst_entry,
-						   ren2->dst_entry,
-						   opt,
 						   ren1->src_entry,
 						   ren2->src_entry);
 
@@ -2802,24 +2790,20 @@ static int process_renames(struct merge_options *opt,
 			if (oid_eq(&src_other.oid, &null_oid) &&
 			    ren1->add_turned_into_rename) {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   NULL,
 							   NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   NULL,
 							   NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
@@ -2848,13 +2832,11 @@ static int process_renames(struct merge_options *opt,
 				 * file, then the merge will be clean.
 				 */
 				setup_rename_conflict_info(RENAME_ADD,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   ren1->src_entry,
 							   NULL);
 			} else
@@ -2876,13 +2858,11 @@ static int process_renames(struct merge_options *opt,
 				}
 				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   NULL,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   NULL,
 							   NULL);
 			}
@@ -3119,15 +3099,15 @@ static int handle_content_merge(struct merge_options *opt,
 	b.mode = b_mode;
 
 	if (ci) {
-		struct diff_filepair *pair1 = ci->pair1;
+		struct diff_filepair *pair1 = ci->ren1->pair;
 
 		path1 = (opt->branch1 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
-		/* If ci->pair2 != NULL, we are in
+		/* If ci->ren2->pair != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
-		path2 = (ci->pair2 ||
+		path2 = ((ci->ren2 && ci->ren2->pair) ||
 			 opt->branch2 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
@@ -3264,7 +3244,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci->pair1, ci->branch1))
+			if (handle_rename_via_dir(opt, ci->ren1->pair, ci->branch1))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3278,7 +3258,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(opt, ci->pair1,
+			if (handle_rename_delete(opt, ci->ren1->pair,
 						 ci->branch1, ci->branch2))
 				clean_merge = -1;
 			break;
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 08/15] merge-recursive: remove ren[12]_other fields from rename_conflict_info

[Elijah Newren]

The ren1_other and ren2_other fields were synthesized from information
in ren1->src_entry and ren2->src_entry.  Since we already have the
necessary information in ren1 and ren2, just use those.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 71 ++++++++++++++---------------------------------
 1 file changed, 21 insertions(+), 50 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index e05f8f22f5..e66b47cfa1 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -242,8 +242,6 @@ struct rename_conflict_info {
 	struct rename *ren2;
 	const char *branch1;
 	const char *branch2;
-	struct diff_filespec ren1_other;
-	struct diff_filespec ren2_other;
 };
 
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
@@ -251,11 +249,8 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      struct rename *ren1,
 					      struct rename *ren2,
 					      const char *branch1,
-					      const char *branch2,
-					      struct stage_data *src_entry1,
-					      struct stage_data *src_entry2)
+					      const char *branch2)
 {
-	int ostage1 = 0, ostage2;
 	struct rename_conflict_info *ci;
 
 	/*
@@ -269,8 +264,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 		setup_rename_conflict_info(rename_type,
 					   opt,
 					   ren2,       ren1,
-					   branch2,    branch1,
-					   src_entry2, src_entry1);
+					   branch2,    branch1);
 		return;
 	}
 
@@ -287,28 +281,6 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	if (ren2) {
 		ci->ren2->dst_entry->rename_conflict_info = ci;
 	}
-
-	/*
-	 * For each rename, there could have been
-	 * modifications on the side of history where that
-	 * file was not renamed.
-	 */
-	if (rename_type == RENAME_ADD ||
-	    rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage1 = opt->branch1 == branch1 ? 3 : 2;
-
-		ci->ren1_other.path = ren1->pair->one->path;
-		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
-		ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
-	}
-
-	if (rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage2 = ostage1 ^ 1;
-
-		ci->ren2_other.path = ren2->pair->one->path;
-		oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
-		ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
-	}
 }
 
 static int show(struct merge_options *opt, int v)
@@ -1688,6 +1660,7 @@ static int handle_rename_add(struct merge_options *opt,
 	/* a was renamed to c, and a separate c was added. */
 	struct diff_filespec *a = ci->ren1->pair->one;
 	struct diff_filespec *c = ci->ren1->pair->two;
+	struct diff_filespec tmp;
 	char *path = c->path;
 	char *prev_path_desc;
 	struct merge_file_info mfi;
@@ -1699,8 +1672,12 @@ static int handle_rename_add(struct merge_options *opt,
 	       a->path, c->path, ci->branch1,
 	       c->path, ci->branch2);
 
+	filespec_from_entry(&tmp, ci->ren1->src_entry, other_stage);
+	tmp.path = a->path;
+
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(opt, a, c, &ci->ren1_other, prev_path_desc,
+	if (merge_mode_and_contents(opt, a, c, &tmp,
+				    prev_path_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi))
 		return -1;
@@ -1850,6 +1827,7 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	struct diff_filespec *b = ci->ren2->pair->one;
 	struct diff_filespec *c1 = ci->ren1->pair->two;
 	struct diff_filespec *c2 = ci->ren2->pair->two;
+	struct diff_filespec tmp1, tmp2;
 	char *path = c1->path; /* == c2->path */
 	char *path_side_1_desc;
 	char *path_side_2_desc;
@@ -1862,12 +1840,17 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	       a->path, c1->path, ci->branch1,
 	       b->path, c2->path, ci->branch2);
 
+	filespec_from_entry(&tmp1, ci->ren1->src_entry, 3);
+	tmp1.path = a->path;
+	filespec_from_entry(&tmp2, ci->ren2->src_entry, 2);
+	tmp2.path = b->path;
+
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	if (merge_mode_and_contents(opt, a, c1, &ci->ren1_other, path_side_1_desc,
+	if (merge_mode_and_contents(opt, a, c1, &tmp1, path_side_1_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(opt, b, &ci->ren2_other, c2, path_side_2_desc,
+	    merge_mode_and_contents(opt, b, &tmp2, c2, path_side_2_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c2))
 		return -1;
@@ -2728,9 +2711,7 @@ static int process_renames(struct merge_options *opt,
 						   ren1,
 						   ren2,
 						   branch1,
-						   branch2,
-						   NULL,
-						   NULL);
+						   branch2);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
 			/* Two different files renamed to the same thing */
 			char *ren2_dst;
@@ -2753,9 +2734,7 @@ static int process_renames(struct merge_options *opt,
 						   ren1,
 						   ren2,
 						   branch1,
-						   branch2,
-						   ren1->src_entry,
-						   ren2->src_entry);
+						   branch2);
 
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
@@ -2794,18 +2773,14 @@ static int process_renames(struct merge_options *opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   branch2,
-							   NULL,
-							   NULL);
+							   branch2);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
 							   opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   branch2,
-							   NULL,
-							   NULL);
+							   branch2);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
 				   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
 				/*
@@ -2836,9 +2811,7 @@ static int process_renames(struct merge_options *opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   branch2,
-							   ren1->src_entry,
-							   NULL);
+							   branch2);
 			} else
 				try_merge = 1;
 
@@ -2862,8 +2835,6 @@ static int process_renames(struct merge_options *opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   NULL,
-							   NULL,
 							   NULL);
 			}
 		}
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 09/15] merge-recursive: track branch where rename occurred in rename struct

[Elijah Newren]

We previously tracked the branch associated with a rename in a separate
field in rename_conflict_info, but since it is directly associated with
the rename it makes more sense to move it into the rename struct.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 113 +++++++++++++++++-----------------------------
 1 file changed, 42 insertions(+), 71 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index e66b47cfa1..f85c276f35 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -211,6 +211,7 @@ struct stage_data {
 
 struct rename {
 	struct diff_filepair *pair;
+	const char *branch; /* branch that the rename occurred on */
 	/*
 	 * Purpose of src_entry and dst_entry:
 	 *
@@ -240,16 +241,12 @@ struct rename_conflict_info {
 	enum rename_type rename_type;
 	struct rename *ren1;
 	struct rename *ren2;
-	const char *branch1;
-	const char *branch2;
 };
 
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      struct merge_options *opt,
 					      struct rename *ren1,
-					      struct rename *ren2,
-					      const char *branch1,
-					      const char *branch2)
+					      struct rename *ren2)
 {
 	struct rename_conflict_info *ci;
 
@@ -260,11 +257,8 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (ren2 && branch1 != opt->branch1) {
-		setup_rename_conflict_info(rename_type,
-					   opt,
-					   ren2,       ren1,
-					   branch2,    branch1);
+	if (ren2 && ren1->branch != opt->branch1) {
+		setup_rename_conflict_info(rename_type, opt, ren2, ren1);
 		return;
 	}
 
@@ -272,8 +266,6 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	ci->rename_type = rename_type;
 	ci->ren1 = ren1;
 	ci->ren2 = ren2;
-	ci->branch1 = branch1;
-	ci->branch2 = branch2;
 
 	ci->ren1->dst_entry->processed = 0;
 	ci->ren1->dst_entry->rename_conflict_info = ci;
@@ -1665,12 +1657,15 @@ static int handle_rename_add(struct merge_options *opt,
 	char *prev_path_desc;
 	struct merge_file_info mfi;
 
-	int other_stage = (ci->branch1 == opt->branch1 ? 3 : 2);
+	const char *rename_branch = ci->ren1->branch;
+	const char *add_branch = (opt->branch1 == rename_branch ?
+				  opt->branch2 : opt->branch1);
+	int other_stage = (ci->ren1->branch == opt->branch1 ? 3 : 2);
 
 	output(opt, 1, _("CONFLICT (rename/add): "
 	       "Rename %s->%s in %s.  Added %s in %s"),
-	       a->path, c->path, ci->branch1,
-	       c->path, ci->branch2);
+	       a->path, c->path, rename_branch,
+	       c->path, add_branch);
 
 	filespec_from_entry(&tmp, ci->ren1->src_entry, other_stage);
 	tmp.path = a->path;
@@ -1685,7 +1680,7 @@ static int handle_rename_add(struct merge_options *opt,
 
 	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
-				     ci->branch1, ci->branch2,
+				     rename_branch, add_branch,
 				     &mfi.oid, mfi.mode,
 				     &ci->ren1->dst_entry->stages[other_stage].oid,
 				     ci->ren1->dst_entry->stages[other_stage].mode);
@@ -1727,14 +1722,14 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
-	       o->path, a->path, ci->branch1,
-	       o->path, b->path, ci->branch2,
+	       o->path, a->path, ci->ren1->branch,
+	       o->path, b->path, ci->ren2->branch,
 	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
 			    a->path, b->path, o->path);
 	if (merge_mode_and_contents(opt, o, a, b, path_desc,
-				    ci->branch1, ci->branch2,
+				    ci->ren1->branch, ci->ren2->branch,
 				    opt->call_depth * 2, &mfi))
 		return -1;
 	free(path_desc);
@@ -1781,14 +1776,15 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		if (add) {
 			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
-						  ci->branch1, ci->branch2,
+						  ci->ren1->branch,
+						  ci->ren2->branch,
 						  &mfi.oid, mfi.mode,
 						  &add->oid, add->mode) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, a->path,
-								ci->branch1,
-								ci->branch2);
+								ci->ren1->branch,
+								ci->ren2->branch);
 			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
@@ -1800,14 +1796,15 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		if (add) {
 			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
-						  ci->branch1, ci->branch2,
+						  ci->ren1->branch,
+						  ci->ren2->branch,
 						  &add->oid, add->mode,
 						  &mfi.oid, mfi.mode) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, b->path,
-								ci->branch2,
-								ci->branch1);
+								ci->ren2->branch,
+								ci->ren1->branch);
 			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
 				return -1;
 			free(new_path);
@@ -1837,8 +1834,8 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
 	       "Rename %s->%s in %s"),
-	       a->path, c1->path, ci->branch1,
-	       b->path, c2->path, ci->branch2);
+	       a->path, c1->path, ci->ren1->branch,
+	       b->path, c2->path, ci->ren2->branch);
 
 	filespec_from_entry(&tmp1, ci->ren1->src_entry, 3);
 	tmp1.path = a->path;
@@ -1858,7 +1855,7 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	free(path_side_2_desc);
 
 	return handle_file_collision(opt, path, a->path, b->path,
-				     ci->branch1, ci->branch2,
+				     ci->ren1->branch, ci->ren2->branch,
 				     &mfi_c1.oid, mfi_c1.mode,
 				     &mfi_c2.oid, mfi_c2.mode);
 }
@@ -2542,6 +2539,7 @@ static void apply_directory_rename_modifications(struct merge_options *opt,
  * information; tree is always equal to either a_tree or b_tree.
  */
 static struct string_list *get_renames(struct merge_options *opt,
+				       const char *branch,
 				       struct diff_queue_struct *pairs,
 				       struct hashmap *dir_renames,
 				       struct hashmap *dir_rename_exclusions,
@@ -2585,6 +2583,7 @@ static struct string_list *get_renames(struct merge_options *opt,
 		re->processed = 0;
 		re->add_turned_into_rename = 0;
 		re->pair = pair;
+		re->branch = branch;
 		item = string_list_lookup(entries, re->pair->one->path);
 		if (!item)
 			re->src_entry = insert_stage_data(re->pair->one->path,
@@ -2639,7 +2638,6 @@ static int process_renames(struct merge_options *opt,
 	for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 		struct string_list *renames1, *renames2Dst;
 		struct rename *ren1 = NULL, *ren2 = NULL;
-		const char *branch1, *branch2;
 		const char *ren1_src, *ren1_dst;
 		struct string_list_item *lookup;
 
@@ -2660,13 +2658,9 @@ static int process_renames(struct merge_options *opt,
 		if (ren1) {
 			renames1 = a_renames;
 			renames2Dst = &b_by_dst;
-			branch1 = opt->branch1;
-			branch2 = opt->branch2;
 		} else {
 			renames1 = b_renames;
 			renames2Dst = &a_by_dst;
-			branch1 = opt->branch2;
-			branch2 = opt->branch1;
 			SWAP(ren2, ren1);
 		}
 
@@ -2706,12 +2700,7 @@ static int process_renames(struct merge_options *opt,
 					     ren1->pair->two,
 					     ren2->pair->two);
 			}
-			setup_rename_conflict_info(rename_type,
-						   opt,
-						   ren1,
-						   ren2,
-						   branch1,
-						   branch2);
+			setup_rename_conflict_info(rename_type, opt, ren1, ren2);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
 			/* Two different files renamed to the same thing */
 			char *ren2_dst;
@@ -2730,11 +2719,7 @@ static int process_renames(struct merge_options *opt,
 			ren2->src_entry->processed = 1;
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
-						   opt,
-						   ren1,
-						   ren2,
-						   branch1,
-						   branch2);
+						   opt, ren1, ren2);
 
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
@@ -2769,18 +2754,10 @@ static int process_renames(struct merge_options *opt,
 			if (oid_eq(&src_other.oid, &null_oid) &&
 			    ren1->add_turned_into_rename) {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   branch2);
+							   opt, ren1, NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   branch2);
+							   opt, ren1, NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
 				   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
 				/*
@@ -2807,11 +2784,7 @@ static int process_renames(struct merge_options *opt,
 				 * file, then the merge will be clean.
 				 */
 				setup_rename_conflict_info(RENAME_ADD,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   branch2);
+							   opt, ren1, NULL);
 			} else
 				try_merge = 1;
 
@@ -2831,11 +2804,7 @@ static int process_renames(struct merge_options *opt,
 				}
 				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   NULL);
+							   opt, ren1, NULL);
 			}
 		}
 	}
@@ -2904,13 +2873,13 @@ static int detect_and_process_renames(struct merge_options *opt,
 		dir_rename_init(dir_re_merge);
 	}
 
-	ri->head_renames  = get_renames(opt, head_pairs,
+	ri->head_renames  = get_renames(opt, opt->branch1, head_pairs,
 					dir_re_merge, dir_re_head, head,
 					common, head, merge, entries,
 					&clean);
 	if (clean < 0)
 		goto cleanup;
-	ri->merge_renames = get_renames(opt, merge_pairs,
+	ri->merge_renames = get_renames(opt, opt->branch2, merge_pairs,
 					dir_re_head, dir_re_merge, merge,
 					common, head, merge, entries,
 					&clean);
@@ -3072,14 +3041,14 @@ static int handle_content_merge(struct merge_options *opt,
 	if (ci) {
 		struct diff_filepair *pair1 = ci->ren1->pair;
 
-		path1 = (opt->branch1 == ci->branch1) ?
+		path1 = (opt->branch1 == ci->ren1->branch) ?
 			pair1->two->path : pair1->one->path;
 		/* If ci->ren2->pair != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
 		path2 = ((ci->ren2 && ci->ren2->pair) ||
-			 opt->branch2 == ci->branch1) ?
+			 opt->branch2 == ci->ren1->branch) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
 		a.path = (char *)path1;
@@ -3157,7 +3126,7 @@ static int handle_content_merge(struct merge_options *opt,
 			}
 
 		}
-		new_path = unique_path(opt, path, ci->branch1);
+		new_path = unique_path(opt, path, ci->ren1->branch);
 		if (is_dirty) {
 			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
@@ -3215,7 +3184,8 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci->ren1->pair, ci->branch1))
+			if (handle_rename_via_dir(opt, ci->ren1->pair,
+						  ci->ren1->branch))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3230,7 +3200,8 @@ static int process_entry(struct merge_options *opt,
 		case RENAME_DELETE:
 			clean_merge = 0;
 			if (handle_rename_delete(opt, ci->ren1->pair,
-						 ci->branch1, ci->branch2))
+						 ci->ren1->branch,
+						 ci->ren1->branch == opt->branch1 ? opt->branch2 : opt->branch1))
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 10/15] merge-recursive: cleanup handle_rename_* function signatures

[Elijah Newren]

Instead of passing various bits and pieces of 'ci', just pass it
directly.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index f85c276f35..ada1c19ed2 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1357,8 +1357,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 }
 
 static int handle_rename_via_dir(struct merge_options *opt,
-				 struct diff_filepair *pair,
-				 const char *rename_branch)
+				 struct rename_conflict_info *ci)
 {
 	/*
 	 * Handle file adds that need to be renamed due to directory rename
@@ -1366,10 +1365,11 @@ static int handle_rename_via_dir(struct merge_options *opt,
 	 * there is no content merge to do; just move the file into the
 	 * desired final location.
 	 */
-	const struct diff_filespec *dest = pair->two;
+	const struct rename *ren = ci->ren1;
+	const struct diff_filespec *dest = ren->pair->two;
 
 	if (!opt->call_depth && would_lose_untracked(opt, dest->path)) {
-		char *alt_path = unique_path(opt, dest->path, rename_branch);
+		char *alt_path = unique_path(opt, dest->path, ren->branch);
 
 		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
 			       "writing to %s instead."),
@@ -1383,8 +1383,8 @@ static int handle_rename_via_dir(struct merge_options *opt,
 			return -1;
 		free(alt_path);
 		return update_stages(opt, dest->path, NULL,
-				     rename_branch == opt->branch1 ? dest : NULL,
-				     rename_branch == opt->branch1 ? NULL : dest);
+				     ren->branch == opt->branch1 ? dest : NULL,
+				     ren->branch == opt->branch1 ? NULL : dest);
 	}
 
 	/* Update dest->path both in index and in worktree */
@@ -1476,12 +1476,14 @@ static int handle_change_delete(struct merge_options *opt,
 }
 
 static int handle_rename_delete(struct merge_options *opt,
-				struct diff_filepair *pair,
-				const char *rename_branch,
-				const char *delete_branch)
+				struct rename_conflict_info *ci)
 {
-	const struct diff_filespec *orig = pair->one;
-	const struct diff_filespec *dest = pair->two;
+	const struct rename *ren = ci->ren1;
+	const struct diff_filespec *orig = ren->pair->one;
+	const struct diff_filespec *dest = ren->pair->two;
+	const char *rename_branch = ren->branch;
+	const char *delete_branch = (opt->branch1 == ren->branch ?
+				     opt->branch2 : opt->branch1);
 
 	if (handle_change_delete(opt,
 				 opt->call_depth ? orig->path : dest->path,
@@ -3184,8 +3186,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci->ren1->pair,
-						  ci->ren1->branch))
+			if (handle_rename_via_dir(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3199,9 +3200,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(opt, ci->ren1->pair,
-						 ci->ren1->branch,
-						 ci->ren1->branch == opt->branch1 ? opt->branch2 : opt->branch1))
+			if (handle_rename_delete(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 11/15] merge-recursive: switch from (oid,mode) pairs to a diff_filespec

[Elijah Newren]

There was a significant inconsistency in the various parts of the API
used in merge-recursive; many places used a pair of (oid, mode) to track
file version/contents, while other parts used a diff_filespec (which
have an oid and mode embedded in it).  This inconsistency caused lots of
places to need to pack and unpack data to call into other functions.
This has been the subject of some past cleanups (see e.g. commit
0270a07ad0b2 ("merge-recursive: remove final remaining caller of
merge_file_one()", 2018-09-19)), but let's just remove the underlying
mess altogether by switching to use diff_filespec.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 483 +++++++++++++++++++++-------------------------
 1 file changed, 215 insertions(+), 268 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index ada1c19ed2..1d2c9e1772 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -201,10 +201,7 @@ enum rename_type {
  * for these (temporary) data.
  */
 struct stage_data {
-	struct {
-		unsigned short mode;
-		struct object_id oid;
-	} stages[4];
+	struct diff_filespec stages[4]; /* mostly for oid & mode; maybe path */
 	struct rename_conflict_info *rename_conflict_info;
 	unsigned processed:1;
 };
@@ -269,7 +266,6 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 
 	ci->ren1->dst_entry->processed = 0;
 	ci->ren1->dst_entry->rename_conflict_info = ci;
-
 	if (ren2) {
 		ci->ren2->dst_entry->rename_conflict_info = ci;
 	}
@@ -326,14 +322,14 @@ static void output_commit_title(struct merge_options *opt, struct commit *commit
 }
 
 static int add_cacheinfo(struct merge_options *opt,
-			 unsigned int mode, const struct object_id *oid,
+			 const struct diff_filespec *blob,
 			 const char *path, int stage, int refresh, int options)
 {
 	struct index_state *istate = opt->repo->index;
 	struct cache_entry *ce;
 	int ret;
 
-	ce = make_cache_entry(istate, mode, oid ? oid : &null_oid, path, stage, 0);
+	ce = make_cache_entry(istate, blob->mode, &blob->oid, path, stage, 0);
 	if (!ce)
 		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
@@ -464,15 +460,14 @@ static void get_files_dirs(struct merge_options *opt, struct tree *tree)
 
 static int get_tree_entry_if_blob(const struct object_id *tree,
 				  const char *path,
-				  struct object_id *hashy,
-				  unsigned short *mode_o)
+				  struct diff_filespec *dfs)
 {
 	int ret;
 
-	ret = get_tree_entry(tree, path, hashy, mode_o);
-	if (S_ISDIR(*mode_o)) {
-		oidcpy(hashy, &null_oid);
-		*mode_o = 0;
+	ret = get_tree_entry(tree, path, &dfs->oid, &dfs->mode);
+	if (S_ISDIR(dfs->mode)) {
+		oidcpy(&dfs->oid, &null_oid);
+		dfs->mode = 0;
 	}
 	return ret;
 }
@@ -487,12 +482,9 @@ static struct stage_data *insert_stage_data(const char *path,
 {
 	struct string_list_item *item;
 	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
-	get_tree_entry_if_blob(&o->object.oid, path,
-			       &e->stages[1].oid, &e->stages[1].mode);
-	get_tree_entry_if_blob(&a->object.oid, path,
-			       &e->stages[2].oid, &e->stages[2].mode);
-	get_tree_entry_if_blob(&b->object.oid, path,
-			       &e->stages[3].oid, &e->stages[3].mode);
+	get_tree_entry_if_blob(&o->object.oid, path, &e->stages[1]);
+	get_tree_entry_if_blob(&a->object.oid, path, &e->stages[2]);
+	get_tree_entry_if_blob(&b->object.oid, path, &e->stages[3]);
 	item = string_list_insert(entries, path);
 	item->util = e;
 	return e;
@@ -648,13 +640,13 @@ static int update_stages(struct merge_options *opt, const char *path,
 		if (remove_file_from_index(opt->repo->index, path))
 			return -1;
 	if (o)
-		if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
+		if (add_cacheinfo(opt, o, path, 1, 0, options))
 			return -1;
 	if (a)
-		if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
+		if (add_cacheinfo(opt, a, path, 2, 0, options))
 			return -1;
 	if (b)
-		if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
+		if (add_cacheinfo(opt, b, path, 3, 0, options))
 			return -1;
 	return 0;
 }
@@ -767,7 +759,7 @@ static int dir_in_way(struct index_state *istate, const char *path,
  * and its oid and mode match the specified values
  */
 static int was_tracked_and_matches(struct merge_options *opt, const char *path,
-				   const struct object_id *oid, unsigned mode)
+				   const struct diff_filespec *blob)
 {
 	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 	struct cache_entry *ce;
@@ -778,7 +770,7 @@ static int was_tracked_and_matches(struct merge_options *opt, const char *path,
 
 	/* See if the file we were tracking before matches */
 	ce = opt->orig_index.cache[pos];
-	return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
+	return (oid_eq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
 }
 
 /*
@@ -903,8 +895,7 @@ static int make_room_for_path(struct merge_options *opt, const char *path)
 }
 
 static int update_file_flags(struct merge_options *opt,
-			     const struct object_id *oid,
-			     unsigned mode,
+			     const struct diff_filespec *contents,
 			     const char *path,
 			     int update_cache,
 			     int update_wd)
@@ -919,7 +910,7 @@ static int update_file_flags(struct merge_options *opt,
 		void *buf;
 		unsigned long size;
 
-		if (S_ISGITLINK(mode)) {
+		if (S_ISGITLINK(contents->mode)) {
 			/*
 			 * We may later decide to recursively descend into
 			 * the submodule directory and update its index
@@ -929,14 +920,16 @@ static int update_file_flags(struct merge_options *opt,
 			goto update_index;
 		}
 
-		buf = read_object_file(oid, &type, &size);
+		buf = read_object_file(&contents->oid, &type, &size);
 		if (!buf)
-			return err(opt, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
+			return err(opt, _("cannot read object %s '%s'"),
+				   oid_to_hex(&contents->oid), path);
 		if (type != OBJ_BLOB) {
-			ret = err(opt, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
+			ret = err(opt, _("blob expected for %s '%s'"),
+				  oid_to_hex(&contents->oid), path);
 			goto free_buf;
 		}
-		if (S_ISREG(mode)) {
+		if (S_ISREG(contents->mode)) {
 			struct strbuf strbuf = STRBUF_INIT;
 			if (convert_to_working_tree(opt->repo->index, path, buf, size, &strbuf)) {
 				free(buf);
@@ -949,12 +942,11 @@ static int update_file_flags(struct merge_options *opt,
 			update_wd = 0;
 			goto free_buf;
 		}
-		if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
+		if (S_ISREG(contents->mode) ||
+		    (!has_symlinks && S_ISLNK(contents->mode))) {
 			int fd;
-			if (mode & 0100)
-				mode = 0777;
-			else
-				mode = 0666;
+			int mode = (contents->mode & 0100 ? 0777 : 0666);
+
 			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 			if (fd < 0) {
 				ret = err(opt, _("failed to open '%s': %s"),
@@ -963,7 +955,7 @@ static int update_file_flags(struct merge_options *opt,
 			}
 			write_in_full(fd, buf, size);
 			close(fd);
-		} else if (S_ISLNK(mode)) {
+		} else if (S_ISLNK(contents->mode)) {
 			char *lnk = xmemdupz(buf, size);
 			safe_create_leading_directories_const(path);
 			unlink(path);
@@ -974,13 +966,13 @@ static int update_file_flags(struct merge_options *opt,
 		} else
 			ret = err(opt,
 				  _("do not know what to do with %06o %s '%s'"),
-				  mode, oid_to_hex(oid), path);
+				  contents->mode, oid_to_hex(&contents->oid), path);
 	free_buf:
 		free(buf);
 	}
 update_index:
 	if (!ret && update_cache)
-		if (add_cacheinfo(opt, mode, oid, path, 0, update_wd,
+		if (add_cacheinfo(opt, contents, path, 0, update_wd,
 				  ADD_CACHE_OK_TO_ADD))
 			return -1;
 	return ret;
@@ -988,18 +980,17 @@ static int update_file_flags(struct merge_options *opt,
 
 static int update_file(struct merge_options *opt,
 		       int clean,
-		       const struct object_id *oid,
-		       unsigned mode,
+		       const struct diff_filespec *contents,
 		       const char *path)
 {
-	return update_file_flags(opt, oid, mode, path, opt->call_depth || clean, !opt->call_depth);
+	return update_file_flags(opt, contents, path,
+				 opt->call_depth || clean, !opt->call_depth);
 }
 
 /* Low level file merging, update and removal */
 
 struct merge_file_info {
-	struct object_id oid;
-	unsigned mode;
+	struct diff_filespec blob; /* mostly use oid & mode; sometimes path */
 	unsigned clean:1,
 		 merge:1;
 };
@@ -1039,6 +1030,7 @@ static int merge_3way(struct merge_options *opt,
 		}
 	}
 
+	assert(a->path && b->path);
 	if (strcmp(a->path, b->path) ||
 	    (opt->ancestor != NULL && strcmp(a->path, o->path) != 0)) {
 		base_name = opt->ancestor == NULL ? NULL :
@@ -1140,6 +1132,11 @@ static void print_commit(struct commit *commit)
 	strbuf_release(&sb);
 }
 
+static int is_valid(const struct diff_filespec *dfs)
+{
+	return dfs->mode != 0 && !is_null_oid(&dfs->oid);
+}
+
 static int merge_submodule(struct merge_options *opt,
 			   struct object_id *result, const char *path,
 			   const struct object_id *base, const struct object_id *a,
@@ -1278,11 +1275,11 @@ static int merge_mode_and_contents(struct merge_options *opt,
 	if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 		result->clean = 0;
 		if (S_ISREG(a->mode)) {
-			result->mode = a->mode;
-			oidcpy(&result->oid, &a->oid);
+			result->blob.mode = a->mode;
+			oidcpy(&result->blob.oid, &a->oid);
 		} else {
-			result->mode = b->mode;
-			oidcpy(&result->oid, &b->oid);
+			result->blob.mode = b->mode;
+			oidcpy(&result->blob.oid, &b->oid);
 		}
 	} else {
 		if (!oid_eq(&a->oid, &o->oid) && !oid_eq(&b->oid, &o->oid))
@@ -1292,9 +1289,9 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		 * Merge modes
 		 */
 		if (a->mode == b->mode || a->mode == o->mode)
-			result->mode = b->mode;
+			result->blob.mode = b->mode;
 		else {
-			result->mode = a->mode;
+			result->blob.mode = a->mode;
 			if (b->mode != o->mode) {
 				result->clean = 0;
 				result->merge = 1;
@@ -1302,9 +1299,9 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		}
 
 		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &o->oid))
-			oidcpy(&result->oid, &b->oid);
+			oidcpy(&result->blob.oid, &b->oid);
 		else if (oid_eq(&b->oid, &o->oid))
-			oidcpy(&result->oid, &a->oid);
+			oidcpy(&result->blob.oid, &a->oid);
 		else if (S_ISREG(a->mode)) {
 			mmbuffer_t result_buf;
 			int ret = 0, merge_status;
@@ -1318,7 +1315,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 
 			if (!ret &&
 			    write_object_file(result_buf.ptr, result_buf.size,
-					      blob_type, &result->oid))
+					      blob_type, &result->blob.oid))
 				ret = err(opt, _("Unable to add %s to database"),
 					  a->path);
 
@@ -1327,7 +1324,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 				return ret;
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(opt, &result->oid,
+			result->clean = merge_submodule(opt, &result->blob.oid,
 							o->path,
 							&o->oid,
 							&a->oid,
@@ -1335,15 +1332,15 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		} else if (S_ISLNK(a->mode)) {
 			switch (opt->recursive_variant) {
 			case MERGE_RECURSIVE_NORMAL:
-				oidcpy(&result->oid, &a->oid);
+				oidcpy(&result->blob.oid, &a->oid);
 				if (!oid_eq(&a->oid, &b->oid))
 					result->clean = 0;
 				break;
 			case MERGE_RECURSIVE_OURS:
-				oidcpy(&result->oid, &a->oid);
+				oidcpy(&result->blob.oid, &a->oid);
 				break;
 			case MERGE_RECURSIVE_THEIRS:
-				oidcpy(&result->oid, &b->oid);
+				oidcpy(&result->blob.oid, &b->oid);
 				break;
 			}
 		} else
@@ -1379,7 +1376,7 @@ static int handle_rename_via_dir(struct merge_options *opt,
 		 * index.  Instead, write to dest->path for the index but
 		 * only at the higher appropriate stage.
 		 */
-		if (update_file(opt, 0, &dest->oid, dest->mode, alt_path))
+		if (update_file(opt, 0, dest, alt_path))
 			return -1;
 		free(alt_path);
 		return update_stages(opt, dest->path, NULL,
@@ -1388,16 +1385,15 @@ static int handle_rename_via_dir(struct merge_options *opt,
 	}
 
 	/* Update dest->path both in index and in worktree */
-	if (update_file(opt, 1, &dest->oid, dest->mode, dest->path))
+	if (update_file(opt, 1, dest, dest->path))
 		return -1;
 	return 0;
 }
 
 static int handle_change_delete(struct merge_options *opt,
 				const char *path, const char *old_path,
-				const struct object_id *o_oid, int o_mode,
-				const struct object_id *changed_oid,
-				int changed_mode,
+				const struct diff_filespec *o,
+				const struct diff_filespec *changed,
 				const char *change_branch,
 				const char *delete_branch,
 				const char *change, const char *change_past)
@@ -1419,7 +1415,7 @@ static int handle_change_delete(struct merge_options *opt,
 		 */
 		ret = remove_file_from_index(opt->repo->index, path);
 		if (!ret)
-			ret = update_file(opt, 0, o_oid, o_mode, update_path);
+			ret = update_file(opt, 0, o, update_path);
 	} else {
 		/*
 		 * Despite the four nearly duplicate messages and argument
@@ -1468,7 +1464,7 @@ static int handle_change_delete(struct merge_options *opt,
 		 * and update_wd=0, but that's a no-op.
 		 */
 		if (change_branch != opt->branch1 || alt_path)
-			ret = update_file(opt, 0, changed_oid, changed_mode, update_path);
+			ret = update_file(opt, 0, changed, update_path);
 	}
 	free(alt_path);
 
@@ -1488,8 +1484,7 @@ static int handle_rename_delete(struct merge_options *opt,
 	if (handle_change_delete(opt,
 				 opt->call_depth ? orig->path : dest->path,
 				 opt->call_depth ? NULL : orig->path,
-				 &orig->oid, orig->mode,
-				 &dest->oid, dest->mode,
+				 orig, dest,
 				 rename_branch, delete_branch,
 				 _("rename"), _("renamed")))
 		return -1;
@@ -1502,31 +1497,16 @@ static int handle_rename_delete(struct merge_options *opt,
 				     rename_branch == opt->branch1 ? NULL : dest);
 }
 
-static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
-						 struct stage_data *entry,
-						 int stage)
-{
-	struct object_id *oid = &entry->stages[stage].oid;
-	unsigned mode = entry->stages[stage].mode;
-	if (mode == 0 || is_null_oid(oid))
-		return NULL;
-	oidcpy(&target->oid, oid);
-	target->mode = mode;
-	return target;
-}
-
 static int handle_file_collision(struct merge_options *opt,
 				 const char *collide_path,
 				 const char *prev_path1,
 				 const char *prev_path2,
 				 const char *branch1, const char *branch2,
-				 const struct object_id *a_oid,
-				 unsigned int a_mode,
-				 const struct object_id *b_oid,
-				 unsigned int b_mode)
+				 struct diff_filespec *a,
+				 struct diff_filespec *b)
 {
 	struct merge_file_info mfi;
-	struct diff_filespec null, a, b;
+	struct diff_filespec null;
 	char *alt_path = NULL;
 	const char *update_path = collide_path;
 
@@ -1540,29 +1520,28 @@ static int handle_file_collision(struct merge_options *opt,
 		return handle_file_collision(opt, collide_path,
 					     prev_path2, prev_path1,
 					     branch2, branch1,
-					     b_oid, b_mode,
-					     a_oid, a_mode);
+					     b, a);
 	}
 
 	/*
 	 * In the recursive case, we just opt to undo renames
 	 */
 	if (opt->call_depth && (prev_path1 || prev_path2)) {
-		/* Put first file (a_oid, a_mode) in its original spot */
+		/* Put first file (a->oid, a->mode) in its original spot */
 		if (prev_path1) {
-			if (update_file(opt, 1, a_oid, a_mode, prev_path1))
+			if (update_file(opt, 1, a, prev_path1))
 				return -1;
 		} else {
-			if (update_file(opt, 1, a_oid, a_mode, collide_path))
+			if (update_file(opt, 1, a, collide_path))
 				return -1;
 		}
 
-		/* Put second file (b_oid, b_mode) in its original spot */
+		/* Put second file (b->oid, b->mode) in its original spot */
 		if (prev_path2) {
-			if (update_file(opt, 1, b_oid, b_mode, prev_path2))
+			if (update_file(opt, 1, b, prev_path2))
 				return -1;
 		} else {
-			if (update_file(opt, 1, b_oid, b_mode, collide_path))
+			if (update_file(opt, 1, b, collide_path))
 				return -1;
 		}
 
@@ -1616,26 +1595,18 @@ static int handle_file_collision(struct merge_options *opt,
 	}
 
 	/* Store things in diff_filespecs for functions that need it */
-	memset(&a, 0, sizeof(struct diff_filespec));
-	memset(&b, 0, sizeof(struct diff_filespec));
-	null.path = a.path = b.path = (char *)collide_path;
+	null.path = (char *)collide_path;
 	oidcpy(&null.oid, &null_oid);
 	null.mode = 0;
-	oidcpy(&a.oid, a_oid);
-	a.mode = a_mode;
-	a.oid_valid = 1;
-	oidcpy(&b.oid, b_oid);
-	b.mode = b_mode;
-	b.oid_valid = 1;
-
-	if (merge_mode_and_contents(opt, &null, &a, &b, collide_path,
+
+	if (merge_mode_and_contents(opt, &null, a, b, collide_path,
 				    branch1, branch2, opt->call_depth * 2, &mfi))
 		return -1;
 	mfi.clean &= !alt_path;
-	if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, update_path))
+	if (update_file(opt, mfi.clean, &mfi.blob, update_path))
 		return -1;
 	if (!mfi.clean && !opt->call_depth &&
-	    update_stages(opt, collide_path, NULL, &a, &b))
+	    update_stages(opt, collide_path, NULL, a, b))
 		return -1;
 	free(alt_path);
 	/*
@@ -1654,7 +1625,6 @@ static int handle_rename_add(struct merge_options *opt,
 	/* a was renamed to c, and a separate c was added. */
 	struct diff_filespec *a = ci->ren1->pair->one;
 	struct diff_filespec *c = ci->ren1->pair->two;
-	struct diff_filespec tmp;
 	char *path = c->path;
 	char *prev_path_desc;
 	struct merge_file_info mfi;
@@ -1669,23 +1639,21 @@ static int handle_rename_add(struct merge_options *opt,
 	       a->path, c->path, rename_branch,
 	       c->path, add_branch);
 
-	filespec_from_entry(&tmp, ci->ren1->src_entry, other_stage);
-	tmp.path = a->path;
-
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(opt, a, c, &tmp,
+	if (merge_mode_and_contents(opt, a, c,
+				    &ci->ren1->src_entry->stages[other_stage],
 				    prev_path_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi))
 		return -1;
 	free(prev_path_desc);
 
+	ci->ren1->dst_entry->stages[other_stage].path = mfi.blob.path = c->path;
 	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
 				     rename_branch, add_branch,
-				     &mfi.oid, mfi.mode,
-				     &ci->ren1->dst_entry->stages[other_stage].oid,
-				     ci->ren1->dst_entry->stages[other_stage].mode);
+				     &mfi.blob,
+				     &ci->ren1->dst_entry->stages[other_stage]);
 }
 
 static char *find_path_for_conflict(struct merge_options *opt,
@@ -1714,7 +1682,6 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 {
 	/* One file was renamed in both branches, but to different names. */
 	struct merge_file_info mfi;
-	struct diff_filespec other;
 	struct diff_filespec *add;
 	struct diff_filespec *o = ci->ren1->pair->one;
 	struct diff_filespec *a = ci->ren1->pair->two;
@@ -1743,7 +1710,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(opt, 0, &mfi.oid, mfi.mode, o->path))
+		if (update_file(opt, 0, &mfi.blob, o->path))
 			return -1;
 
 		/*
@@ -1754,16 +1721,16 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * such cases, we should keep the added file around,
 		 * resolving the conflict at that path in its favor.
 		 */
-		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
-		if (add) {
-			if (update_file(opt, 0, &add->oid, add->mode, a->path))
+		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		if (is_valid(add)) {
+			if (update_file(opt, 0, add, a->path))
 				return -1;
 		}
 		else
 			remove_file_from_index(opt->repo->index, a->path);
-		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
-		if (add) {
-			if (update_file(opt, 0, &add->oid, add->mode, b->path))
+		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		if (is_valid(add)) {
+			if (update_file(opt, 0, add, b->path))
 				return -1;
 		}
 		else
@@ -1774,40 +1741,42 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * rename/add collision.  If not, we can write the file out
 		 * to the specified location.
 		 */
-		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
-		if (add) {
+		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		if (is_valid(add)) {
+			add->path = mfi.blob.path = a->path;
 			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
 						  ci->ren1->branch,
 						  ci->ren2->branch,
-						  &mfi.oid, mfi.mode,
-						  &add->oid, add->mode) < 0)
+						  &mfi.blob, add) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, a->path,
 								ci->ren1->branch,
 								ci->ren2->branch);
-			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
+			if (update_file(opt, 0, &mfi.blob,
+					new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
 			if (update_stages(opt, a->path, NULL, a, NULL))
 				return -1;
 		}
 
-		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
-		if (add) {
+		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		if (is_valid(add)) {
+			add->path = mfi.blob.path = b->path;
 			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
 						  ci->ren1->branch,
 						  ci->ren2->branch,
-						  &add->oid, add->mode,
-						  &mfi.oid, mfi.mode) < 0)
+						  add, &mfi.blob) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, b->path,
 								ci->ren2->branch,
 								ci->ren1->branch);
-			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
+			if (update_file(opt, 0, &mfi.blob,
+					new_path ? new_path : b->path))
 				return -1;
 			free(new_path);
 			if (update_stages(opt, b->path, NULL, NULL, b))
@@ -1826,12 +1795,12 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	struct diff_filespec *b = ci->ren2->pair->one;
 	struct diff_filespec *c1 = ci->ren1->pair->two;
 	struct diff_filespec *c2 = ci->ren2->pair->two;
-	struct diff_filespec tmp1, tmp2;
 	char *path = c1->path; /* == c2->path */
 	char *path_side_1_desc;
 	char *path_side_2_desc;
 	struct merge_file_info mfi_c1;
 	struct merge_file_info mfi_c2;
+	int ostage1, ostage2;
 
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
@@ -1839,27 +1808,31 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	       a->path, c1->path, ci->ren1->branch,
 	       b->path, c2->path, ci->ren2->branch);
 
-	filespec_from_entry(&tmp1, ci->ren1->src_entry, 3);
-	tmp1.path = a->path;
-	filespec_from_entry(&tmp2, ci->ren2->src_entry, 2);
-	tmp2.path = b->path;
-
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	if (merge_mode_and_contents(opt, a, c1, &tmp1, path_side_1_desc,
+	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
+	ostage2 = ostage1 ^ 1;
+	ci->ren1->src_entry->stages[ostage1].path = a->path;
+	ci->ren2->src_entry->stages[ostage2].path = b->path;
+	if (merge_mode_and_contents(opt, a, c1,
+				    &ci->ren1->src_entry->stages[ostage1],
+				    path_side_1_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(opt, b, &tmp2, c2, path_side_2_desc,
+	    merge_mode_and_contents(opt, b,
+				    &ci->ren2->src_entry->stages[ostage2],
+				    c2, path_side_2_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c2))
 		return -1;
 	free(path_side_1_desc);
 	free(path_side_2_desc);
+	mfi_c1.blob.path = path;
+	mfi_c2.blob.path = path;
 
 	return handle_file_collision(opt, path, a->path, b->path,
 				     ci->ren1->branch, ci->ren2->branch,
-				     &mfi_c1.oid, mfi_c1.mode,
-				     &mfi_c2.oid, mfi_c2.mode);
+				     &mfi_c1.blob, &mfi_c2.blob);
 }
 
 /*
@@ -2722,7 +2695,6 @@ static int process_renames(struct merge_options *opt,
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
 						   opt, ren1, ren2);
-
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
 			/* we only use sha1 and mode of these */
@@ -2771,8 +2743,7 @@ static int process_renames(struct merge_options *opt,
 				 * update_file().
 				 */
 				if (update_file_flags(opt,
-						      &ren1->pair->two->oid,
-						      ren1->pair->two->mode,
+						      ren1->pair->two,
 						      ren1_dst,
 						      1, /* update_cache */
 						      0  /* update_wd    */))
@@ -2923,11 +2894,6 @@ static void final_cleanup_renames(struct rename_info *re_info)
 	final_cleanup_rename(re_info->merge_renames);
 }
 
-static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
-{
-	return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
-}
-
 static int read_oid_strbuf(struct merge_options *opt,
 			   const struct object_id *oid,
 			   struct strbuf *dst)
@@ -2947,10 +2913,8 @@ static int read_oid_strbuf(struct merge_options *opt,
 }
 
 static int blob_unchanged(struct merge_options *opt,
-			  const struct object_id *o_oid,
-			  unsigned o_mode,
-			  const struct object_id *a_oid,
-			  unsigned a_mode,
+			  const struct diff_filespec *o,
+			  const struct diff_filespec *a,
 			  int renormalize, const char *path)
 {
 	struct strbuf obuf = STRBUF_INIT;
@@ -2958,16 +2922,15 @@ static int blob_unchanged(struct merge_options *opt,
 	int ret = 0; /* assume changed for safety */
 	const struct index_state *idx = opt->repo->index;
 
-	if (a_mode != o_mode)
+	if (a->mode != o->mode)
 		return 0;
-	if (oid_eq(o_oid, a_oid))
+	if (oid_eq(&o->oid, &a->oid))
 		return 1;
 	if (!renormalize)
 		return 0;
 
-	assert(o_oid && a_oid);
-	if (read_oid_strbuf(opt, o_oid, &obuf) ||
-	    read_oid_strbuf(opt, a_oid, &abuf))
+	if (read_oid_strbuf(opt, &o->oid, &obuf) ||
+	    read_oid_strbuf(opt, &a->oid, &abuf))
 		goto error_return;
 	/*
 	 * Note: binary | is used so that both renormalizations are
@@ -2986,30 +2949,26 @@ static int blob_unchanged(struct merge_options *opt,
 
 static int handle_modify_delete(struct merge_options *opt,
 				const char *path,
-				struct object_id *o_oid, int o_mode,
-				struct object_id *a_oid, int a_mode,
-				struct object_id *b_oid, int b_mode)
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b)
 {
 	const char *modify_branch, *delete_branch;
-	struct object_id *changed_oid;
-	int changed_mode;
+	const struct diff_filespec *changed;
 
-	if (a_oid) {
+	if (is_valid(a)) {
 		modify_branch = opt->branch1;
 		delete_branch = opt->branch2;
-		changed_oid = a_oid;
-		changed_mode = a_mode;
+		changed = a;
 	} else {
 		modify_branch = opt->branch2;
 		delete_branch = opt->branch1;
-		changed_oid = b_oid;
-		changed_mode = b_mode;
+		changed = b;
 	}
 
 	return handle_change_delete(opt,
 				    path, NULL,
-				    o_oid, o_mode,
-				    changed_oid, changed_mode,
+				    o, changed,
 				    modify_branch, delete_branch,
 				    _("modify"), _("modified"));
 }
@@ -3017,50 +2976,24 @@ static int handle_modify_delete(struct merge_options *opt,
 static int handle_content_merge(struct merge_options *opt,
 				const char *path,
 				int is_dirty,
-				struct object_id *o_oid, int o_mode,
-				struct object_id *a_oid, int a_mode,
-				struct object_id *b_oid, int b_mode,
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b,
 				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
-	const char *path1 = NULL, *path2 = NULL;
 	struct merge_file_info mfi;
-	struct diff_filespec one, a, b;
 	unsigned df_conflict_remains = 0;
 
-	if (!o_oid) {
+	if (!is_valid(o))
 		reason = _("add/add");
-		o_oid = (struct object_id *)&null_oid;
-	}
-	one.path = a.path = b.path = (char *)path;
-	oidcpy(&one.oid, o_oid);
-	one.mode = o_mode;
-	oidcpy(&a.oid, a_oid);
-	a.mode = a_mode;
-	oidcpy(&b.oid, b_oid);
-	b.mode = b_mode;
-
-	if (ci) {
-		struct diff_filepair *pair1 = ci->ren1->pair;
-
-		path1 = (opt->branch1 == ci->ren1->branch) ?
-			pair1->two->path : pair1->one->path;
-		/* If ci->ren2->pair != NULL, we are in
-		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
-		 * normal rename.
-		 */
-		path2 = ((ci->ren2 && ci->ren2->pair) ||
-			 opt->branch2 == ci->ren1->branch) ?
-			pair1->two->path : pair1->one->path;
-		one.path = pair1->one->path;
-		a.path = (char *)path1;
-		b.path = (char *)path2;
-
-		if (dir_in_way(opt->repo->index, path, !opt->call_depth,
-			       S_ISGITLINK(pair1->two->mode)))
-			df_conflict_remains = 1;
-	}
-	if (merge_mode_and_contents(opt, &one, &a, &b, path,
+
+	assert(o->path && a->path && b->path);
+	if (ci && dir_in_way(opt->repo->index, path, !opt->call_depth,
+			     S_ISGITLINK(ci->ren1->pair->two->mode)))
+		df_conflict_remains = 1;
+
+	if (merge_mode_and_contents(opt, o, a, b, path,
 				    opt->branch1, opt->branch2,
 				    opt->call_depth * 2, &mfi))
 		return -1;
@@ -3071,14 +3004,13 @@ static int handle_content_merge(struct merge_options *opt,
 	 *   b) The merge matches what was in HEAD (content, mode, pathname)
 	 *   c) The target path is usable (i.e. not involved in D/F conflict)
 	 */
-	if (mfi.clean &&
-	    was_tracked_and_matches(opt, path, &mfi.oid, mfi.mode) &&
+	if (mfi.clean && was_tracked_and_matches(opt, path, &mfi.blob) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
 		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(opt, mfi.mode, &mfi.oid, path,
+		if (add_cacheinfo(opt, &mfi.blob, path,
 				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
@@ -3098,12 +3030,12 @@ static int handle_content_merge(struct merge_options *opt,
 	}
 
 	if (!mfi.clean) {
-		if (S_ISGITLINK(mfi.mode))
+		if (S_ISGITLINK(mfi.blob.mode))
 			reason = _("submodule");
 		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
 		if (ci && !df_conflict_remains)
-			if (update_stages(opt, path, &one, &a, &b))
+			if (update_stages(opt, path, o, a, b))
 				return -1;
 	}
 
@@ -3113,17 +3045,14 @@ static int handle_content_merge(struct merge_options *opt,
 			remove_file_from_index(opt->repo->index, path);
 		} else {
 			if (!mfi.clean) {
-				if (update_stages(opt, path, &one, &a, &b))
+				if (update_stages(opt, path, o, a, b))
 					return -1;
 			} else {
 				int file_from_stage2 = was_tracked(opt, path);
-				struct diff_filespec merged;
-				oidcpy(&merged.oid, &mfi.oid);
-				merged.mode = mfi.mode;
 
 				if (update_stages(opt, path, NULL,
-						  file_from_stage2 ? &merged : NULL,
-						  file_from_stage2 ? NULL : &merged))
+						  file_from_stage2 ? &mfi.blob : NULL,
+						  file_from_stage2 ? NULL : &mfi.blob))
 					return -1;
 			}
 
@@ -3134,28 +3063,27 @@ static int handle_content_merge(struct merge_options *opt,
 			       path);
 		}
 		output(opt, 1, _("Adding as %s instead"), new_path);
-		if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path)) {
+		if (update_file(opt, 0, &mfi.blob, new_path)) {
 			free(new_path);
 			return -1;
 		}
 		free(new_path);
 		mfi.clean = 0;
-	} else if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, path))
+	} else if (update_file(opt, mfi.clean, &mfi.blob, path))
 		return -1;
 	return !is_dirty && mfi.clean;
 }
 
 static int handle_rename_normal(struct merge_options *opt,
 				const char *path,
-				struct object_id *o_oid, unsigned int o_mode,
-				struct object_id *a_oid, unsigned int a_mode,
-				struct object_id *b_oid, unsigned int b_mode,
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b,
 				struct rename_conflict_info *ci)
 {
 	/* Merge the content and write it out */
 	return handle_content_merge(opt, path, was_dirty(opt, path),
-				    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
-				    ci);
+				    o, a, b, ci);
 }
 
 /* Per entry merge function */
@@ -3164,24 +3092,36 @@ static int process_entry(struct merge_options *opt,
 {
 	int clean_merge = 1;
 	int normalize = opt->renormalize;
-	unsigned o_mode = entry->stages[1].mode;
-	unsigned a_mode = entry->stages[2].mode;
-	unsigned b_mode = entry->stages[3].mode;
-	struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
-	struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
-	struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
+
+	struct diff_filespec *o = &entry->stages[1];
+	struct diff_filespec *a = &entry->stages[2];
+	struct diff_filespec *b = &entry->stages[3];
+	int o_valid = is_valid(o);
+	int a_valid = is_valid(a);
+	int b_valid = is_valid(b);
+	o->path = a->path = b->path = (char*)path;
 
 	entry->processed = 1;
 	if (entry->rename_conflict_info) {
 		struct rename_conflict_info *ci = entry->rename_conflict_info;
+		struct diff_filespec *temp;
+
+		/*
+		 * For cases with a single rename, {o,a,b}->path have all been
+		 * set to the rename target path; we need to set two of these
+		 * back to the rename source.
+		 * For rename/rename conflicts, we'll manually fix paths below.
+		 */
+		temp = (opt->branch1 == ci->ren1->branch) ? b : a;
+		o->path = temp->path = ci->ren1->pair->one->path;
+		if (ci->ren2) {
+			assert(opt->branch1 == ci->ren1->branch);
+		}
+
 		switch (ci->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
-			clean_merge = handle_rename_normal(opt,
-							   path,
-							   o_oid, o_mode,
-							   a_oid, a_mode,
-							   b_oid, b_mode,
+			clean_merge = handle_rename_normal(opt, path, o, a, b,
 							   ci);
 			break;
 		case RENAME_VIA_DIR:
@@ -3204,11 +3144,27 @@ static int process_entry(struct merge_options *opt,
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
+			/*
+			 * Manually fix up paths; note:
+			 * ren[12]->pair->one->path are equal.
+			 */
+			o->path = ci->ren1->pair->one->path;
+			a->path = ci->ren1->pair->two->path;
+			b->path = ci->ren2->pair->two->path;
+
 			clean_merge = 0;
 			if (handle_rename_rename_1to2(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_TWO_FILES_TO_ONE:
+			/*
+			 * Manually fix up paths; note,
+			 * ren[12]->pair->two->path are actually equal.
+			 */
+			o->path = NULL;
+			a->path = ci->ren1->pair->two->path;
+			b->path = ci->ren2->pair->two->path;
+
 			/*
 			 * Probably unclean merge, but if the two renamed
 			 * files merge cleanly and the two resulting files
@@ -3221,57 +3177,53 @@ static int process_entry(struct merge_options *opt,
 			entry->processed = 0;
 			break;
 		}
-	} else if (o_oid && (!a_oid || !b_oid)) {
+	} else if (o_valid && (!a_valid || !b_valid)) {
 		/* Case A: Deleted in one */
-		if ((!a_oid && !b_oid) ||
-		    (!b_oid && blob_unchanged(opt, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
-		    (!a_oid && blob_unchanged(opt, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
+		if ((!a_valid && !b_valid) ||
+		    (!b_valid && blob_unchanged(opt, o, a, normalize, path)) ||
+		    (!a_valid && blob_unchanged(opt, o, b, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
-			if (a_oid)
+			if (a_valid)
 				output(opt, 2, _("Removing %s"), path);
 			/* do not touch working file if it did not exist */
-			remove_file(opt, 1, path, !a_oid);
+			remove_file(opt, 1, path, !a_valid);
 		} else {
 			/* Modify/delete; deleted side may have put a directory in the way */
 			clean_merge = 0;
-			if (handle_modify_delete(opt, path, o_oid, o_mode,
-						 a_oid, a_mode, b_oid, b_mode))
+			if (handle_modify_delete(opt, path, o, a, b))
 				clean_merge = -1;
 		}
-	} else if ((!o_oid && a_oid && !b_oid) ||
-		   (!o_oid && !a_oid && b_oid)) {
+	} else if ((!o_valid && a_valid && !b_valid) ||
+		   (!o_valid && !a_valid && b_valid)) {
 		/* Case B: Added in one. */
 		/* [nothing|directory] -> ([nothing|directory], file) */
 
 		const char *add_branch;
 		const char *other_branch;
-		unsigned mode;
-		const struct object_id *oid;
 		const char *conf;
+		const struct diff_filespec *contents;
 
-		if (a_oid) {
+		if (a_valid) {
 			add_branch = opt->branch1;
 			other_branch = opt->branch2;
-			mode = a_mode;
-			oid = a_oid;
+			contents = a;
 			conf = _("file/directory");
 		} else {
 			add_branch = opt->branch2;
 			other_branch = opt->branch1;
-			mode = b_mode;
-			oid = b_oid;
+			contents = b;
 			conf = _("directory/file");
 		}
 		if (dir_in_way(opt->repo->index, path,
-			       !opt->call_depth && !S_ISGITLINK(a_mode),
+			       !opt->call_depth && !S_ISGITLINK(a->mode),
 			       0)) {
 			char *new_path = unique_path(opt, path, add_branch);
 			clean_merge = 0;
 			output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
 			       "Adding %s as %s"),
 			       conf, path, other_branch, path, new_path);
-			if (update_file(opt, 0, oid, mode, new_path))
+			if (update_file(opt, 0, contents, new_path))
 				clean_merge = -1;
 			else if (opt->call_depth)
 				remove_file_from_index(opt->repo->index, path);
@@ -3279,11 +3231,11 @@ static int process_entry(struct merge_options *opt,
 		} else {
 			output(opt, 2, _("Adding %s"), path);
 			/* do not overwrite file if already present */
-			if (update_file_flags(opt, oid, mode, path, 1, !a_oid))
+			if (update_file_flags(opt, contents, path, 1, !a_valid))
 				clean_merge = -1;
 		}
-	} else if (a_oid && b_oid) {
-		if (!o_oid) {
+	} else if (a_valid && b_valid) {
+		if (!o_valid) {
 			/* Case C: Added in both (check for same permissions) */
 			output(opt, 1,
 			       _("CONFLICT (add/add): Merge conflict in %s"),
@@ -3292,24 +3244,19 @@ static int process_entry(struct merge_options *opt,
 							    path, NULL, NULL,
 							    opt->branch1,
 							    opt->branch2,
-							    a_oid, a_mode,
-							    b_oid, b_mode);
+							    a, b);
 		} else {
 			/* case D: Modified in both, but differently. */
 			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(opt, path,
-							   is_dirty,
-							   o_oid, o_mode,
-							   a_oid, a_mode,
-							   b_oid, b_mode,
-							   NULL);
+			clean_merge = handle_content_merge(opt, path, is_dirty,
+							   o, a, b, NULL);
 		}
-	} else if (!o_oid && !a_oid && !b_oid) {
+	} else if (!o_valid && !a_valid && !b_valid) {
 		/*
 		 * this entry was deleted altogether. a_mode == 0 means
 		 * we had that path and want to actively remove it.
 		 */
-		remove_file(opt, 1, path, !a_mode);
+		remove_file(opt, 1, path, !a->mode);
 	} else
 		BUG("fatal merge failure, shouldn't happen.");
 
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 12/15] t6043: fix copied test description to match its purpose

[Elijah Newren]

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 t/t6043-merge-rename-directories.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
index 62c564707b..fe205be607 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6043-merge-rename-directories.sh
@@ -3910,7 +3910,7 @@ test_expect_success '12a-check: Moving one directory hierarchy into another' '
 #         To which, I can do no more than shrug my shoulders and say that
 #         even simple rules give weird results when given weird inputs.
 
-test_expect_success '12b-setup: Moving one directory hierarchy into another' '
+test_expect_success '12b-setup: Moving two directory hierarchies into each other' '
 	test_create_repo 12b &&
 	(
 		cd 12b &&
@@ -3940,7 +3940,7 @@ test_expect_success '12b-setup: Moving one directory hierarchy into another' '
 	)
 '
 
-test_expect_success '12b-check: Moving one directory hierarchy into another' '
+test_expect_success '12b-check: Moving two directory hierarchies into each other' '
 	(
 		cd 12b &&
 
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 13/15] merge-recursive: track information associated with directory renames

[Elijah Newren]

Directory rename detection previously silently applied.  In order to
allow printing information about paths that changed or printing a
conflict notification (and only doing so near other potential conflict
messages associated with the paths), save this information inside the
rename struct for later use.  A subsequent patch will make use of the
additional information.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 1d2c9e1772..938a526b20 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -207,8 +207,16 @@ struct stage_data {
 };
 
 struct rename {
+	unsigned processed:1;
 	struct diff_filepair *pair;
 	const char *branch; /* branch that the rename occurred on */
+	/*
+	 * If directory rename detection affected this rename, what was its
+	 * original type ('A' or 'R') and it's original destination before
+	 * the directory rename (otherwise, '\0' and NULL for these two vars).
+	 */
+	char dir_rename_original_type;
+	char *dir_rename_original_dest;
 	/*
 	 * Purpose of src_entry and dst_entry:
 	 *
@@ -230,8 +238,6 @@ struct rename {
 	 */
 	struct stage_data *src_entry;
 	struct stage_data *dst_entry;
-	unsigned add_turned_into_rename:1;
-	unsigned processed:1;
 };
 
 struct rename_conflict_info {
@@ -2484,16 +2490,18 @@ static void apply_directory_rename_modifications(struct merge_options *opt,
 		       &re->dst_entry->stages[stage].oid,
 		       &re->dst_entry->stages[stage].mode);
 
-	/* Update pair status */
-	if (pair->status == 'A') {
-		/*
-		 * Recording rename information for this add makes it look
-		 * like a rename/delete conflict.  Make sure we can
-		 * correctly handle this as an add that was moved to a new
-		 * directory instead of reporting a rename/delete conflict.
-		 */
-		re->add_turned_into_rename = 1;
-	}
+	/*
+	 * Record the original change status (or 'type' of change).  If it
+	 * was originally an add ('A'), this lets us differentiate later
+	 * between a RENAME_DELETE conflict and RENAME_VIA_DIR (they
+	 * otherwise look the same).  If it was originally a rename ('R'),
+	 * this lets us remember and report accurately about the transitive
+	 * renaming that occurred via the directory rename detection.  Also,
+	 * record the original destination name.
+	 */
+	re->dir_rename_original_type = pair->status;
+	re->dir_rename_original_dest = pair->two->path;
+
 	/*
 	 * We don't actually look at pair->status again, but it seems
 	 * pedagogically correct to adjust it.
@@ -2556,9 +2564,10 @@ static struct string_list *get_renames(struct merge_options *opt,
 
 		re = xmalloc(sizeof(*re));
 		re->processed = 0;
-		re->add_turned_into_rename = 0;
 		re->pair = pair;
 		re->branch = branch;
+		re->dir_rename_original_type = '\0';
+		re->dir_rename_original_dest = NULL;
 		item = string_list_lookup(entries, re->pair->one->path);
 		if (!item)
 			re->src_entry = insert_stage_data(re->pair->one->path,
@@ -2726,7 +2735,7 @@ static int process_renames(struct merge_options *opt,
 			try_merge = 0;
 
 			if (oid_eq(&src_other.oid, &null_oid) &&
-			    ren1->add_turned_into_rename) {
+			    ren1->dir_rename_original_type == 'A') {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
 							   opt, ren1, NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 14/15] merge-recursive: give callers of handle_content_merge() access to contents

[Elijah Newren]

Pass a merge_file_info struct to handle_content_merge() so that the
callers can access the oid and mode of the result afterward.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 938a526b20..2edfa01e43 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -2982,7 +2982,8 @@ static int handle_modify_delete(struct merge_options *opt,
 				    _("modify"), _("modified"));
 }
 
-static int handle_content_merge(struct merge_options *opt,
+static int handle_content_merge(struct merge_file_info *mfi,
+				struct merge_options *opt,
 				const char *path,
 				int is_dirty,
 				const struct diff_filespec *o,
@@ -2991,7 +2992,6 @@ static int handle_content_merge(struct merge_options *opt,
 				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
-	struct merge_file_info mfi;
 	unsigned df_conflict_remains = 0;
 
 	if (!is_valid(o))
@@ -3004,7 +3004,7 @@ static int handle_content_merge(struct merge_options *opt,
 
 	if (merge_mode_and_contents(opt, o, a, b, path,
 				    opt->branch1, opt->branch2,
-				    opt->call_depth * 2, &mfi))
+				    opt->call_depth * 2, mfi))
 		return -1;
 
 	/*
@@ -3013,13 +3013,13 @@ static int handle_content_merge(struct merge_options *opt,
 	 *   b) The merge matches what was in HEAD (content, mode, pathname)
 	 *   c) The target path is usable (i.e. not involved in D/F conflict)
 	 */
-	if (mfi.clean && was_tracked_and_matches(opt, path, &mfi.blob) &&
+	if (mfi->clean && was_tracked_and_matches(opt, path, &mfi->blob) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
 		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(opt, &mfi.blob, path,
+		if (add_cacheinfo(opt, &mfi->blob, path,
 				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
@@ -3035,11 +3035,11 @@ static int handle_content_merge(struct merge_options *opt,
 			ce = opt->repo->index->cache[pos];
 			ce->ce_flags |= CE_SKIP_WORKTREE;
 		}
-		return mfi.clean;
+		return mfi->clean;
 	}
 
-	if (!mfi.clean) {
-		if (S_ISGITLINK(mfi.blob.mode))
+	if (!mfi->clean) {
+		if (S_ISGITLINK(mfi->blob.mode))
 			reason = _("submodule");
 		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
@@ -3053,15 +3053,15 @@ static int handle_content_merge(struct merge_options *opt,
 		if (opt->call_depth) {
 			remove_file_from_index(opt->repo->index, path);
 		} else {
-			if (!mfi.clean) {
+			if (!mfi->clean) {
 				if (update_stages(opt, path, o, a, b))
 					return -1;
 			} else {
 				int file_from_stage2 = was_tracked(opt, path);
 
 				if (update_stages(opt, path, NULL,
-						  file_from_stage2 ? &mfi.blob : NULL,
-						  file_from_stage2 ? NULL : &mfi.blob))
+						  file_from_stage2 ? &mfi->blob : NULL,
+						  file_from_stage2 ? NULL : &mfi->blob))
 					return -1;
 			}
 
@@ -3072,15 +3072,15 @@ static int handle_content_merge(struct merge_options *opt,
 			       path);
 		}
 		output(opt, 1, _("Adding as %s instead"), new_path);
-		if (update_file(opt, 0, &mfi.blob, new_path)) {
+		if (update_file(opt, 0, &mfi->blob, new_path)) {
 			free(new_path);
 			return -1;
 		}
 		free(new_path);
-		mfi.clean = 0;
-	} else if (update_file(opt, mfi.clean, &mfi.blob, path))
+		mfi->clean = 0;
+	} else if (update_file(opt, mfi->clean, &mfi->blob, path))
 		return -1;
-	return !is_dirty && mfi.clean;
+	return !is_dirty && mfi->clean;
 }
 
 static int handle_rename_normal(struct merge_options *opt,
@@ -3091,7 +3091,8 @@ static int handle_rename_normal(struct merge_options *opt,
 				struct rename_conflict_info *ci)
 {
 	/* Merge the content and write it out */
-	return handle_content_merge(opt, path, was_dirty(opt, path),
+	struct merge_file_info mfi;
+	return handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
 				    o, a, b, ci);
 }
 
@@ -3256,8 +3257,10 @@ static int process_entry(struct merge_options *opt,
 							    a, b);
 		} else {
 			/* case D: Modified in both, but differently. */
+			struct merge_file_info mfi;
 			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(opt, path, is_dirty,
+			clean_merge = handle_content_merge(&mfi, opt, path,
+							   is_dirty,
 							   o, a, b, NULL);
 		}
 	} else if (!o_valid && !a_valid && !b_valid) {
-- 
2.21.0.211.g078f4bef79.dirty

[PATCH v2 15/15] merge-recursive: switch directory rename detection default

[Elijah Newren]

When all of x/a, x/b, and x/c have moved to z/a, z/b, and z/c on one
branch, there is a question about whether x/d added on a different
branch should remain at x/d or appear at z/d when the two branches are
merged.  There are different possible viewpoints here:

  A) The file was placed at x/d; it's unrelated to the other files in
     x/ so it doesn't matter that all the files from x/ moved to z/ on
     one branch; x/d should still remain at x/d.

  B) x/d is related to the other files in x/, and x/ was renamed to z/;
     therefore x/d should be moved to z/d.

Since there was no ability to detect directory renames prior to
git-2.18, users experienced (A) regardless of context.  Choice (B) was
implemented in git-2.18, with no option to go back to (A), and has been
in use since.  However, one user reported that the merge results did not
match their expectations, making the change of default problematic,
especially since there was no notice printed when directory rename
detection moved files.

Note that there is also a third possibility here:

  C) There are different answers depending on the context and content
     that cannot be determined by git, so this is a conflict.  Use a
     higher stage in the index to record the conflict and notify the
     user of the potential issue instead of silently selecting a
     resolution for them.

Add an option for users to specify their preference for whether to use
directory rename detection, and default to (C).  Even when directory
rename detection is on, add notice messages about files moved into new
directories.

As a sidenote, x/d did not have to be a new file here; it could have
already existed at some other path and been renamed to x/d, with
directory rename detection just renaming it again to z/d.  Thus, it's
not just new files, but also a modification to all rename types (normal
renames, rename/add, rename/delete, rename/rename(1to1),
rename/rename(1to2), and rename/rename(2to1)).

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 Documentation/config/merge.txt         |  19 +-
 merge-recursive.c                      | 151 ++++++--
 t/t3401-rebase-and-am-rename.sh        |   8 +-
 t/t6043-merge-rename-directories.sh    | 458 ++++++++++++++++++++++---
 t/t6046-merge-skip-unneeded-updates.sh |   8 +-
 5 files changed, 557 insertions(+), 87 deletions(-)

diff --git a/Documentation/config/merge.txt b/Documentation/config/merge.txt
index d389c73929..6a313937f8 100644
--- a/Documentation/config/merge.txt
+++ b/Documentation/config/merge.txt
@@ -39,9 +39,22 @@ merge.renameLimit::
 	is turned off.
 
 merge.renames::
-	Whether and how Git detects renames.  If set to "false",
-	rename detection is disabled. If set to "true", basic rename
-	detection is enabled.  Defaults to the value of diff.renames.
+	Whether Git detects renames.  If set to "false", rename detection
+	is disabled. If set to "true", basic rename detection is enabled.
+	Defaults to the value of diff.renames.
+
+merge.directoryRenames::
+	Whether Git detects directory renames, affecting what happens at
+	merge time to new files added to a directory on one side of
+	history when that directory was renamed on the other side of
+	history.  If merge.directoryRenames is set to "false", directory
+	rename detection is disabled, meaning that such new files will be
+	left behind in the old directory.  If set to "true", directory
+	rename detection is enabled, meaning that such new files will be
+	moved into the new directory.  If set to "conflict", a conflict
+	will be reported for such paths.  If merge.renames is false,
+	merge.directoryRenames is ignored and treated as false.  Defaults
+	to "conflict".
 
 merge.renormalize::
 	Tell Git that canonical representation of files in the
diff --git a/merge-recursive.c b/merge-recursive.c
index 2edfa01e43..a86f37b333 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1370,30 +1370,39 @@ static int handle_rename_via_dir(struct merge_options *opt,
 	 */
 	const struct rename *ren = ci->ren1;
 	const struct diff_filespec *dest = ren->pair->two;
+	char *file_path = dest->path;
+	int mark_conflicted = (opt->detect_directory_renames == 1);
+	assert(ren->dir_rename_original_dest);
 
 	if (!opt->call_depth && would_lose_untracked(opt, dest->path)) {
-		char *alt_path = unique_path(opt, dest->path, ren->branch);
-
+		mark_conflicted = 1;
+		file_path = unique_path(opt, dest->path, ren->branch);
 		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
-			       "writing to %s instead."),
-		       dest->path, alt_path);
+				 "writing to %s instead."),
+		       dest->path, file_path);
+	}
+
+	if (mark_conflicted) {
 		/*
-		 * Write the file in worktree at alt_path, but not in the
-		 * index.  Instead, write to dest->path for the index but
-		 * only at the higher appropriate stage.
+		 * Write the file in worktree at file_path.  In the index,
+		 * only record the file at dest->path in the appropriate
+		 * higher stage.
 		 */
-		if (update_file(opt, 0, dest, alt_path))
+		if (update_file(opt, 0, dest, file_path))
 			return -1;
-		free(alt_path);
-		return update_stages(opt, dest->path, NULL,
-				     ren->branch == opt->branch1 ? dest : NULL,
-				     ren->branch == opt->branch1 ? NULL : dest);
+		if (file_path != dest->path)
+			free(file_path);
+		if (update_stages(opt, dest->path, NULL,
+				  ren->branch == opt->branch1 ? dest : NULL,
+				  ren->branch == opt->branch1 ? NULL : dest))
+			return -1;
+		return 0; /* not clean, but conflicted */
+	} else {
+		/* Update dest->path both in index and in worktree */
+		if (update_file(opt, 1, dest, dest->path))
+			return -1;
+		return 1; /* clean */
 	}
-
-	/* Update dest->path both in index and in worktree */
-	if (update_file(opt, 1, dest, dest->path))
-		return -1;
-	return 0;
 }
 
 static int handle_change_delete(struct merge_options *opt,
@@ -3090,10 +3099,88 @@ static int handle_rename_normal(struct merge_options *opt,
 				const struct diff_filespec *b,
 				struct rename_conflict_info *ci)
 {
-	/* Merge the content and write it out */
+	struct rename *ren = ci->ren1;
 	struct merge_file_info mfi;
-	return handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
-				    o, a, b, ci);
+	int clean;
+	int side = (ren->branch == opt->branch1 ? 2 : 3);
+
+	/* Merge the content and write it out */
+	clean = handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
+				     o, a, b, ci);
+
+	if (clean && opt->detect_directory_renames == 1 &&
+	    ren->dir_rename_original_dest) {
+		if (update_stages(opt, path,
+				  NULL,
+				  side == 2 ? &mfi.blob : NULL,
+				  side == 2 ? NULL : &mfi.blob))
+			return -1;
+		clean = 0; /* not clean, but conflicted */
+	}
+	return clean;
+}
+
+static void dir_rename_warning(const char *msg,
+			       int is_add,
+			       int clean,
+			       struct merge_options *opt,
+			       struct rename *ren)
+{
+	const char *other_branch;
+	other_branch = (ren->branch == opt->branch1 ?
+			opt->branch2 : opt->branch1);
+	if (is_add) {
+		output(opt, clean ? 2 : 1, msg,
+		       ren->pair->one->path, ren->branch,
+		       other_branch, ren->pair->two->path);
+		return;
+	}
+	output(opt, clean ? 2 : 1, msg,
+	       ren->pair->one->path, ren->dir_rename_original_dest, ren->branch,
+	       other_branch, ren->pair->two->path);
+}
+static int warn_about_dir_renamed_entries(struct merge_options *opt,
+					  struct rename *ren)
+{
+	const char *msg;
+	int clean = 1, is_add;
+
+	if (!ren)
+		return clean;
+
+	/* Return early if ren was not affected/created by a directory rename */
+	if (!ren->dir_rename_original_dest)
+		return clean;
+
+	/* Sanity checks */
+	assert(opt->detect_directory_renames > 0);
+	assert(ren->dir_rename_original_type == 'A' ||
+	       ren->dir_rename_original_type == 'R');
+
+	/* Check whether to treat directory renames as a conflict */
+	clean = (opt->detect_directory_renames == 2);
+
+	is_add = (ren->dir_rename_original_type == 'A');
+	if (ren->dir_rename_original_type == 'A' && clean) {
+		msg = _("Path updated: %s added in %s inside a "
+			"directory that was renamed in %s; moving it to %s.");
+	} else if (ren->dir_rename_original_type == 'A' && !clean) {
+		msg = _("CONFLICT (file location): %s added in %s "
+			"inside a directory that was renamed in %s, "
+			"suggesting it should perhaps be moved to %s.");
+	} else if (ren->dir_rename_original_type == 'R' && clean) {
+		msg = _("Path updated: %s renamed to %s in %s, inside a "
+			"directory that was renamed in %s; moving it to %s.");
+	} else if (ren->dir_rename_original_type == 'R' && !clean) {
+		msg = _("CONFLICT (file location): %s renamed to %s in %s, "
+			"inside a directory that was renamed in %s, "
+			"suggesting it should perhaps be moved to %s.");
+	} else {
+		BUG("Impossible dir_rename_original_type/clean combination");
+	}
+	dir_rename_warning(msg, is_add, clean, opt, ren);
+
+	return clean;
 }
 
 /* Per entry merge function */
@@ -3115,6 +3202,10 @@ static int process_entry(struct merge_options *opt,
 	if (entry->rename_conflict_info) {
 		struct rename_conflict_info *ci = entry->rename_conflict_info;
 		struct diff_filespec *temp;
+		int path_clean;
+
+		path_clean = warn_about_dir_renamed_entries(opt, ci->ren1);
+		path_clean &= warn_about_dir_renamed_entries(opt, ci->ren2);
 
 		/*
 		 * For cases with a single rename, {o,a,b}->path have all been
@@ -3135,9 +3226,7 @@ static int process_entry(struct merge_options *opt,
 							   ci);
 			break;
 		case RENAME_VIA_DIR:
-			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci))
-				clean_merge = -1;
+			clean_merge = handle_rename_via_dir(opt, ci);
 			break;
 		case RENAME_ADD:
 			/*
@@ -3187,6 +3276,8 @@ static int process_entry(struct merge_options *opt,
 			entry->processed = 0;
 			break;
 		}
+		if (path_clean < clean_merge)
+			clean_merge = path_clean;
 	} else if (o_valid && (!a_valid || !b_valid)) {
 		/* Case A: Deleted in one */
 		if ((!a_valid && !b_valid) ||
@@ -3558,6 +3649,20 @@ static void merge_recursive_config(struct merge_options *opt)
 		opt->merge_detect_rename = git_config_rename("merge.renames", value);
 		free(value);
 	}
+	if (!git_config_get_string("merge.directoryrenames", &value)) {
+		if (!strcasecmp(value, "true"))
+			opt->detect_directory_renames = 2;
+		else if (!strcasecmp(value, "false"))
+			opt->detect_directory_renames = 0;
+		else if (!strcasecmp(value, "conflict"))
+			opt->detect_directory_renames = 1;
+		else {
+			error(_("Invalid value for merge.directoryRenames: %s"),
+			      value);
+			opt->detect_directory_renames = 1;
+		}
+		free(value);
+	}
 	git_config(git_xmerge_config, NULL);
 }
 
diff --git a/t/t3401-rebase-and-am-rename.sh b/t/t3401-rebase-and-am-rename.sh
index e0b5111993..a0b9438b22 100755
--- a/t/t3401-rebase-and-am-rename.sh
+++ b/t/t3401-rebase-and-am-rename.sh
@@ -42,7 +42,7 @@ test_expect_success 'rebase --interactive: directory rename detected' '
 		git checkout B^0 &&
 
 		set_fake_editor &&
-		FAKE_LINES="1" git rebase --interactive A &&
+		FAKE_LINES="1" git -c merge.directoryRenames=true rebase --interactive A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -58,7 +58,7 @@ test_expect_failure 'rebase (am): directory rename detected' '
 
 		git checkout B^0 &&
 
-		git rebase A &&
+		git -c merge.directoryRenames=true rebase A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -74,7 +74,7 @@ test_expect_success 'rebase --merge: directory rename detected' '
 
 		git checkout B^0 &&
 
-		git rebase --merge A &&
+		git -c merge.directoryRenames=true rebase --merge A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -92,7 +92,7 @@ test_expect_failure 'am: directory rename detected' '
 
 		git format-patch -1 B &&
 
-		git am --3way 0001*.patch &&
+		git -c merge.directoryRenames=true am --3way 0001*.patch &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
index fe205be607..50b7543483 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6043-merge-rename-directories.sh
@@ -75,7 +75,7 @@ test_expect_success '1a-check: Simple directory rename detection' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -142,7 +142,7 @@ test_expect_success '1b-check: Merge a directory with another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -201,7 +201,7 @@ test_expect_success '1c-check: Transitive renaming' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -270,7 +270,7 @@ test_expect_success '1d-check: Directory renames cause a rename/rename(2to1) con
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 
 		git ls-files -s >out &&
@@ -350,7 +350,7 @@ test_expect_success '1e-check: Renamed directory, with all files being renamed t
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -416,7 +416,7 @@ test_expect_success '1f-check: Split a directory into two other directories' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -497,7 +497,7 @@ test_expect_success '2a-check: Directory split into two on one side, with equal
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT.*directory rename split" out &&
 
 		git ls-files -s >out &&
@@ -559,7 +559,7 @@ test_expect_success '2b-check: Directory split into two on one side, with equal
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -640,7 +640,7 @@ test_expect_success '3a-check: Avoid implicit rename if involved as source on ot
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -705,7 +705,7 @@ test_expect_success '3b-check: Avoid implicit rename if involved as source on cu
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/d.*x/d.*w/d out &&
 		test_i18ngrep ! CONFLICT.*rename/rename.*y/d out &&
 
@@ -826,7 +826,7 @@ test_expect_success '4a-check: Directory split, with original directory still pr
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -915,7 +915,7 @@ test_expect_success '5a-check: Merge directories, other side adds files to origi
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT.*implicit dir rename" out &&
 
 		git ls-files -s >out &&
@@ -989,7 +989,7 @@ test_expect_success '5b-check: Rename/delete in order to get add/add/add conflic
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
 
 		git ls-files -s >out &&
@@ -1069,7 +1069,7 @@ test_expect_success '5c-check: Transitive rename would cause rename/rename/renam
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*z/d" out &&
 		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
 
@@ -1153,7 +1153,7 @@ test_expect_success '5d-check: Directory/file/file conflict due to directory ren
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (file/directory).*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1243,7 +1243,7 @@ test_expect_success '6a-check: Tricky rename/delete' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*z/c.*y/c" out &&
 
 		git ls-files -s >out &&
@@ -1308,7 +1308,7 @@ test_expect_success '6b-check: Same rename done on both sides' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1370,7 +1370,7 @@ test_expect_success '6c-check: Rename only done on same side' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1432,7 +1432,7 @@ test_expect_success '6d-check: We do not always want transitive renaming' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1495,7 +1495,7 @@ test_expect_success '6e-check: Add/add from one side' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -1591,7 +1591,7 @@ test_expect_success '7a-check: rename-dir vs. rename-dir (NOT split evenly) PLUS
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*z/b.*y/b.*w/b" out &&
 		test_i18ngrep "CONFLICT (rename/rename).*z/c.*y/c.*x/c" out &&
 
@@ -1663,7 +1663,7 @@ test_expect_success '7b-check: rename/rename(2to1), but only due to transitive r
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 
 		git ls-files -s >out &&
@@ -1740,7 +1740,7 @@ test_expect_success '7c-check: rename/rename(1to...2or3); transitive rename may
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1804,7 +1804,7 @@ test_expect_success '7d-check: transitive rename involved in rename/delete; how
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1894,7 +1894,7 @@ test_expect_success '7e-check: transitive rename in rename/delete AND dirs in th
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1985,7 +1985,7 @@ test_expect_success '8a-check: Dual-directory rename, one into the others way' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -2063,7 +2063,7 @@ test_expect_success '8b-check: Dual-directory rename, one into the others way, w
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -2135,7 +2135,7 @@ test_expect_success '8c-check: modify/delete or rename+modify/delete' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (modify/delete).* z/d" out &&
 
 		git ls-files -s >out &&
@@ -2212,7 +2212,7 @@ test_expect_success '8d-check: rename/delete...or not?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2287,7 +2287,7 @@ test_expect_success '8e-check: Both sides rename, one side adds to original dire
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/c.*y/c.*w/c out &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/b.*y/b.*w/b out &&
 
@@ -2374,7 +2374,7 @@ test_expect_success '9a-check: Inner renamed directory within outer renamed dire
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 7 out &&
@@ -2444,7 +2444,7 @@ test_expect_success '9b-check: Transitive rename with content merge' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2534,7 +2534,7 @@ test_expect_success '9c-check: Doubly transitive rename?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "WARNING: Avoiding applying x -> z rename to x/f" out &&
 
 		git ls-files -s >out &&
@@ -2622,7 +2622,7 @@ test_expect_success '9d-check: N-way transitive rename?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "WARNING: Avoiding applying z -> y rename to z/t" out &&
 		test_i18ngrep "WARNING: Avoiding applying y -> x rename to y/a" out &&
 		test_i18ngrep "WARNING: Avoiding applying x -> w rename to x/b" out &&
@@ -2704,7 +2704,7 @@ test_expect_success C_LOCALE_OUTPUT '9e-check: N-to-1 whammo' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		grep "CONFLICT (implicit dir rename): Cannot map more than one path to combined/yo" out >error_line &&
 		grep -q dir1/yo error_line &&
 		grep -q dir2/yo error_line &&
@@ -2782,7 +2782,7 @@ test_expect_success '9f-check: Renamed directory that only contained immediate s
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2849,7 +2849,7 @@ test_expect_failure '9g-check: Renamed directory that only contained immediate s
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2918,7 +2918,7 @@ test_expect_success '9h-check: Avoid dir rename on merely modified path' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2993,7 +2993,7 @@ test_expect_success '10a-check: Overwrite untracked with normal rename/delete' '
 		echo very >z/c &&
 		echo important >z/d &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "The following untracked working tree files would be overwritten by merge" err &&
 
 		git ls-files -s >out &&
@@ -3061,7 +3061,7 @@ test_expect_success '10b-check: Overwrite untracked with dir rename + delete' '
 		echo important >y/d &&
 		echo contents >y/e &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/delete).*Version B\^0 of y/d left in tree at y/d~B\^0" out &&
 		test_i18ngrep "Error: Refusing to lose untracked file at y/e; writing to y/e~B\^0 instead" out &&
 
@@ -3137,7 +3137,7 @@ test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)
 		git checkout A^0 &&
 		echo important >y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~B\^0 instead" out &&
 
@@ -3174,7 +3174,7 @@ test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)
 		mkdir y &&
 		echo important >y/c &&
 
-		test_must_fail git merge -s recursive A^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~HEAD instead" out &&
 
@@ -3249,7 +3249,7 @@ test_expect_success '10d-check: Delete untracked with dir rename/rename(2to1)' '
 		git checkout A^0 &&
 		echo important >y/wham &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/wham" out &&
 
@@ -3327,7 +3327,7 @@ test_expect_failure '10e-check: Does git complain about untracked file that is n
 		mkdir z &&
 		echo random >z/c &&
 
-		git merge -s recursive B^0 >out 2>err &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep ! "following untracked working tree files would be overwritten by merge" err &&
 
 		git ls-files -s >out &&
@@ -3407,7 +3407,7 @@ test_expect_success '11a-check: Avoid losing dirty contents with simple rename'
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		test_seq 1 10 >expected &&
@@ -3479,7 +3479,7 @@ test_expect_success '11b-check: Avoid losing dirty file involved in directory re
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		git merge -s recursive B^0 >out 2>err &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		grep -q stuff z/c &&
@@ -3554,7 +3554,7 @@ test_expect_success '11c-check: Avoid losing not-uptodate with rename + D/F conf
 		git checkout A^0 &&
 		echo stuff >>y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "following files would be overwritten by merge" err &&
 
 		grep -q stuff y/c &&
@@ -3621,7 +3621,7 @@ test_expect_success '11d-check: Avoid losing not-uptodate with rename + D/F conf
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		grep -q stuff z/c &&
@@ -3700,7 +3700,7 @@ test_expect_success '11e-check: Avoid deleting not-uptodate with dir rename/rena
 		git checkout A^0 &&
 		echo mods >>y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose dirty file at y/c" out &&
 
@@ -3782,7 +3782,7 @@ test_expect_success '11f-check: Avoid deleting not-uptodate with dir rename/rena
 		git checkout A^0 &&
 		echo important >>y/wham &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose dirty file at y/wham" out &&
 
@@ -3870,7 +3870,7 @@ test_expect_success '12a-check: Moving one directory hierarchy into another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -3946,7 +3946,7 @@ test_expect_success '12b-check: Moving two directory hierarchies into each other
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -4016,7 +4016,7 @@ test_expect_success '12c-check: Moving one directory hierarchy into another w/ c
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -u >out &&
 		test_line_count = 12 out &&
@@ -4051,4 +4051,356 @@ test_expect_success '12c-check: Moving one directory hierarchy into another w/ c
 	)
 '
 
+###########################################################################
+# SECTION 13: Checking informational and conflict messages
+#
+# A year after directory rename detection became the default, it was
+# instead decided to report conflicts on the pathname on the basis that
+# some users may expect the new files added or moved into a directory to
+# be unrelated to all the other files in that directory, and thus that
+# directory rename detection is unexpected.  Test that the messages printed
+# match our expectation.
+###########################################################################
+
+# Testcase 13a, Basic directory rename with newly added files
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d,e/f}
+#   Expected: y/{b,c,d,e/f}, with notices/conflicts for both y/d and y/e/f
+
+test_expect_success '13a-setup: messages for newly added files' '
+	test_create_repo 13a &&
+	(
+		cd 13a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo d >z/d &&
+		mkdir z/e &&
+		echo f >z/e/f &&
+		git add z/d z/e/f &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13a-check(conflict): messages for newly added files' '
+	(
+		cd 13a &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT..file.location.*z/e/f.added.in.B^0.*y/e/f out &&
+		test_i18ngrep CONFLICT..file.location.*z/d.added.in.B^0.*y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/[de]" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d &&
+		test_path_is_missing z/e/f &&
+		test_path_is_file    y/e/f
+	)
+'
+
+test_expect_success '13a-check(info): messages for newly added files' '
+	(
+		cd 13a &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep Path.updated:.*z/e/f.added.in.B^0.*y/e/f out &&
+		test_i18ngrep Path.updated:.*z/d.added.in.B^0.*y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/[de]" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d &&
+		test_path_is_missing z/e/f &&
+		test_path_is_file    y/e/f
+	)
+'
+
+# Testcase 13b, Transitive rename with conflicted content merge and default
+#               "conflict" setting
+#   (Related to testcase 1c, 9b)
+#   Commit O: z/{b,c},   x/d_1
+#   Commit A: y/{b,c},   x/d_2
+#   Commit B: z/{b,c,d_3}
+#   Expected: y/{b,c,d_merged}, with two conflict messages for y/d,
+#             one about content, and one about file location
+
+test_expect_success '13b-setup: messages for transitive rename with conflicted content' '
+	test_create_repo 13b &&
+	(
+		cd 13b &&
+
+		mkdir x &&
+		mkdir z &&
+		test_seq 1 10 >x/d &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add x z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		echo 11 >>x/d &&
+		git add x/d &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo eleven >>x/d &&
+		git mv x/d z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13b-check(conflict): messages for transitive rename with conflicted content' '
+	(
+		cd 13b &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT.*content.*Merge.conflict.in.y/d out &&
+		test_i18ngrep CONFLICT..file.location.*x/d.renamed.to.z/d.*moved.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+test_expect_success '13b-check(info): messages for transitive rename with conflicted content' '
+	(
+		cd 13b &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT.*content.*Merge.conflict.in.y/d out &&
+		test_i18ngrep Path.updated:.*x/d.renamed.to.z/d.in.B^0.*moving.it.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+# Testcase 13c, Rename/rename(1to1) due to directory rename
+#   Commit O: z/{b,c},   x/{d,e}
+#   Commit A: y/{b,c,d}, x/e
+#   Commit B: z/{b,c,d}, x/e
+#   Expected: y/{b,c,d}, with info or conflict messages for d (
+#             A: renamed x/d -> z/d; B: renamed z/ -> y/ AND renamed x/d to y/d
+#             One could argue A had partial knowledge of what was done with
+#             d and B had full knowledge, but that's a slippery slope as
+#             shown in testcase 13d.
+
+test_expect_success '13c-setup: messages for rename/rename(1to1) via transitive rename' '
+	test_create_repo 13c &&
+	(
+		cd 13c &&
+
+		mkdir x &&
+		mkdir z &&
+		test_seq 1 10 >x/d &&
+		echo e >x/e &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add x z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git mv x/d y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13c-check(conflict): messages for rename/rename(1to1) via transitive rename' '
+	(
+		cd 13c &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT..file.location.*x/d.renamed.to.z/d.*moved.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+test_expect_success '13c-check(info): messages for rename/rename(1to1) via transitive rename' '
+	(
+		cd 13c &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep Path.updated:.*x/d.renamed.to.z/d.in.B^0.*moving.it.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+# Testcase 13d, Rename/rename(1to1) due to directory rename on both sides
+#   Commit O: a/{z,y}, b/x,     c/w
+#   Commit A: a/z,     b/{y,x}, d/w
+#   Commit B: a/z,     d/x,     c/{y,w}
+#   Expected: a/z, d/{y,x,w} with no file location conflict for x
+#             Easy cases:
+#               * z is always in a; so it stays in a.
+#               * x starts in b, only modified on one side to move into d/
+#               * w starts in c, only modified on one side to move into d/
+#             Hard case:
+#               * A renames a/y to b/y, and B renames b/->d/ => a/y -> d/y
+#               * B renames a/y to c/y, and A renames c/->d/ => a/y -> d/y
+#               No conflict in where a/y ends up, so put it in d/y.
+
+test_expect_success '13d-setup: messages for rename/rename(1to1) via dual transitive rename' '
+	test_create_repo 13d &&
+	(
+		cd 13d &&
+
+		mkdir a &&
+		mkdir b &&
+		mkdir c &&
+		echo z >a/z &&
+		echo y >a/y &&
+		echo x >b/x &&
+		echo w >c/w &&
+		git add a b c &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv a/y b/ &&
+		git mv c/ d/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv a/y c/ &&
+		git mv b/ d/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13d-check(conflict): messages for rename/rename(1to1) via dual transitive rename' '
+	(
+		cd 13d &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT..file.location.*a/y.renamed.to.b/y.*moved.to.d/y out &&
+		test_i18ngrep CONFLICT..file.location.*a/y.renamed.to.c/y.*moved.to.d/y out &&
+
+		git ls-files >paths &&
+		! grep b/ paths &&
+		! grep c/ paths &&
+		grep "d/y" paths &&
+
+		test_path_is_missing b/y &&
+		test_path_is_missing c/y &&
+		test_path_is_file    d/y
+	)
+'
+
+test_expect_success '13d-check(info): messages for rename/rename(1to1) via dual transitive rename' '
+	(
+		cd 13d &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep Path.updated.*a/y.renamed.to.b/y.*moving.it.to.d/y out &&
+		test_i18ngrep Path.updated.*a/y.renamed.to.c/y.*moving.it.to.d/y out &&
+
+		git ls-files >paths &&
+		! grep b/ paths &&
+		! grep c/ paths &&
+		grep "d/y" paths &&
+
+		test_path_is_missing b/y &&
+		test_path_is_missing c/y &&
+		test_path_is_file    d/y
+	)
+'
+
 test_done
diff --git a/t/t6046-merge-skip-unneeded-updates.sh b/t/t6046-merge-skip-unneeded-updates.sh
index 38e24f787c..3a47623ed3 100755
--- a/t/t6046-merge-skip-unneeded-updates.sh
+++ b/t/t6046-merge-skip-unneeded-updates.sh
@@ -466,7 +466,7 @@ test_expect_success '3a-check-L: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout A^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
@@ -495,7 +495,7 @@ test_expect_success '3a-check-R: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout B^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
@@ -560,7 +560,7 @@ test_expect_success '3b-check-L: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout A^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
@@ -589,7 +589,7 @@ test_expect_success '3b-check-R: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout B^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
-- 
2.21.0.211.g078f4bef79.dirty

Re: [PATCH v2 15/15] merge-recursive: switch directory rename detection default

[Ævar Arnfjörð Bjarmason]

On Sat, Mar 30 2019, Elijah Newren wrote:

I may have more, just quickly skimming this for the first time...

>  merge.renames::
> -	Whether and how Git detects renames.  If set to "false",
> -	rename detection is disabled. If set to "true", basic rename
> -	detection is enabled.  Defaults to the value of diff.renames.
> +	Whether Git detects renames.  If set to "false", rename detection
> +	is disabled. If set to "true", basic rename detection is enabled.
> +	Defaults to the value of diff.renames.
> [...]
> +	if (!git_config_get_string("merge.directoryrenames", &value)) {
> +		if (!strcasecmp(value, "true"))
> +			opt->detect_directory_renames = 2;
> +		else if (!strcasecmp(value, "false"))
> +			opt->detect_directory_renames = 0;
> +		else if (!strcasecmp(value, "conflict"))
> +			opt->detect_directory_renames = 1;
> +		else {
> +			error(_("Invalid value for merge.directoryRenames: %s"),
> +			      value);
> +			opt->detect_directory_renames = 1;
> +		}
> +		free(value);
> +	}

Instead of making your own true/false parser you can use
git_parse_maybe_bool(). See what we do for merge.ff:

    builtin/merge.c-617-    else if (!strcmp(k, "merge.ff")) {
    builtin/merge.c:618:            int boolval = git_parse_maybe_bool(v);
    builtin/merge.c-619-            if (0 <= boolval) {
    builtin/merge.c-620-                    fast_forward = boolval ? FF_ALLOW : FF_NO;
    builtin/merge.c-621-            } else if (v && !strcmp(v, "only")) {
    builtin/merge.c-622-                    fast_forward = FF_ONLY;
    builtin/merge.c-623-            } /* do not barf on values from future versions of git */
    builtin/merge.c-624-            return 0;

Small nit, but allows us to document "this config takse bool or ..."
without having different verions of "bool" in various places.

Also, I don't care personally, but this also violates the "if one thing
requires braces put it on all the if/else arms" in CodingGuidelines.

Re: [PATCH v2 15/15] merge-recursive: switch directory rename detection default

[Elijah Newren]

On Sat, Mar 30, 2019 at 2:12 AM Ævar Arnfjörð Bjarmason
<avarab@gmail.com> wrote:
> On Sat, Mar 30 2019, Elijah Newren wrote:
>
> I may have more, just quickly skimming this for the first time...
>
> >  merge.renames::
> > -     Whether and how Git detects renames.  If set to "false",
> > -     rename detection is disabled. If set to "true", basic rename
> > -     detection is enabled.  Defaults to the value of diff.renames.
> > +     Whether Git detects renames.  If set to "false", rename detection
> > +     is disabled. If set to "true", basic rename detection is enabled.
> > +     Defaults to the value of diff.renames.
> > [...]
> > +     if (!git_config_get_string("merge.directoryrenames", &value)) {
> > +             if (!strcasecmp(value, "true"))
> > +                     opt->detect_directory_renames = 2;
> > +             else if (!strcasecmp(value, "false"))
> > +                     opt->detect_directory_renames = 0;
> > +             else if (!strcasecmp(value, "conflict"))
> > +                     opt->detect_directory_renames = 1;
> > +             else {
> > +                     error(_("Invalid value for merge.directoryRenames: %s"),
> > +                           value);
> > +                     opt->detect_directory_renames = 1;
> > +             }
> > +             free(value);
> > +     }
>
> Instead of making your own true/false parser you can use
> git_parse_maybe_bool(). See what we do for merge.ff:
>
>     builtin/merge.c-617-    else if (!strcmp(k, "merge.ff")) {
>     builtin/merge.c:618:            int boolval = git_parse_maybe_bool(v);
>     builtin/merge.c-619-            if (0 <= boolval) {
>     builtin/merge.c-620-                    fast_forward = boolval ? FF_ALLOW : FF_NO;
>     builtin/merge.c-621-            } else if (v && !strcmp(v, "only")) {
>     builtin/merge.c-622-                    fast_forward = FF_ONLY;
>     builtin/merge.c-623-            } /* do not barf on values from future versions of git */
>     builtin/merge.c-624-            return 0;
>
> Small nit, but allows us to document "this config takse bool or ..."
> without having different verions of "bool" in various places.
>
> Also, I don't care personally, but this also violates the "if one thing
> requires braces put it on all the if/else arms" in CodingGuidelines.

Thanks for taking a look.  I'll make the fix, and wait for other
feedback before resending.

[PATCH v3 00/15] Switch directory rename detection default

[Elijah Newren]

This series adds a new configuration option, merge.directoryRenames,
for setting how to make use of directory rename detection heuristics.
The default becomes "conflict", meaning that conflicts are reported
instead of silently moving paths according to the heuristics.  Also,
even when merge.directoryRenames config setting is "true", this series
changes behavior in that it now prints informational messages about
paths that are adjusted by the directory rename detection heuristics.

Changes since v2 (range-diff below):
  * Made use of git_parse_maybe_bool() as suggested by Ævar, and made
    the parsing of the merge.directoryRenames setting look more like
    that for merge.ff.

I didn't get much review of round 2, which maybe means everyone is
happy with what they see.  If anyone would like to take a look at just
part of the series, the pieces I'd most like folks to look at are:
  * Patch 15, particularly looking over the new testcases (13a-13d) in
    t6043 and the documentation.
  * Should I have switched the type of "mode" from 'unsigned short' to
    'unsigned' instead of vice-versa in patch 1?
  * Similarly, does anyone have a reason to prefer oid,mode pair over
    using a diff_filespec (in patch 11 I convert half the sites to the
    latter)?


Elijah Newren (15):
  Use 'unsigned short' for mode, like diff_filespec does
  merge-recursive: rename merge_options argument from 'o' to 'opt'
  merge-recursive: rename diff_filespec 'one' to 'o'
  merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
  merge-recursive: use 'ci' for rename_conflict_info variable name
  merge-recursive: move some struct declarations together
  merge-recursive: shrink rename_conflict_info
  merge-recursive: remove ren[12]_other fields from rename_conflict_info
  merge-recursive: track branch where rename occurred in rename struct
  merge-recursive: cleanup handle_rename_* function signatures
  merge-recursive: switch from (oid,mode) pairs to a diff_filespec
  t6043: fix copied test description to match its purpose
  merge-recursive: track information associated with directory renames
  merge-recursive: give callers of handle_content_merge() access to
    contents
  merge-recursive: switch directory rename detection default

 Documentation/config/merge.txt         |   19 +-
 archive.c                              |    2 +-
 blame.c                                |    2 +-
 blame.h                                |    2 +-
 builtin/rm.c                           |    2 +-
 builtin/update-index.c                 |    2 +-
 cache.h                                |    2 +-
 fsck.c                                 |    2 +-
 line-log.c                             |    2 +-
 match-trees.c                          |    8 +-
 merge-recursive.c                      | 1853 ++++++++++++------------
 notes.c                                |    2 +-
 sha1-name.c                            |    2 +-
 t/t3401-rebase-and-am-rename.sh        |    8 +-
 t/t6043-merge-rename-directories.sh    |  462 +++++-
 t/t6046-merge-skip-unneeded-updates.sh |    8 +-
 tree-diff.c                            |    2 +-
 tree-walk.c                            |    6 +-
 tree-walk.h                            |    6 +-
 19 files changed, 1367 insertions(+), 1025 deletions(-)

Range-diff:
 1:  bb5b410a61 =  1:  bb5b410a61 Use 'unsigned short' for mode, like diff_filespec does
 2:  f91c28257e =  2:  f91c28257e merge-recursive: rename merge_options argument from 'o' to 'opt'
 3:  e3fe8baa15 =  3:  e3fe8baa15 merge-recursive: rename diff_filespec 'one' to 'o'
 4:  c6bd963ffb =  4:  c6bd963ffb merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
 5:  eca30e7571 =  5:  eca30e7571 merge-recursive: use 'ci' for rename_conflict_info variable name
 6:  07f0d5fa8e =  6:  07f0d5fa8e merge-recursive: move some struct declarations together
 7:  4cdd1ecbcb =  7:  4cdd1ecbcb merge-recursive: shrink rename_conflict_info
 8:  3490324bdd =  8:  3490324bdd merge-recursive: remove ren[12]_other fields from rename_conflict_info
 9:  fb73a2c55d =  9:  fb73a2c55d merge-recursive: track branch where rename occurred in rename struct
10:  124ee08ed8 = 10:  124ee08ed8 merge-recursive: cleanup handle_rename_* function signatures
11:  78a5916efe = 11:  78a5916efe merge-recursive: switch from (oid,mode) pairs to a diff_filespec
12:  a8309326c1 = 12:  a8309326c1 t6043: fix copied test description to match its purpose
13:  b362f4db1e = 13:  b362f4db1e merge-recursive: track information associated with directory renames
14:  2e0258a358 = 14:  2e0258a358 merge-recursive: give callers of handle_content_merge() access to contents
15:  719c25afaf ! 15:  428cdf62b3 merge-recursive: switch directory rename detection default
    @@ -262,17 +262,12 @@
      		free(value);
      	}
     +	if (!git_config_get_string("merge.directoryrenames", &value)) {
    -+		if (!strcasecmp(value, "true"))
    -+			opt->detect_directory_renames = 2;
    -+		else if (!strcasecmp(value, "false"))
    -+			opt->detect_directory_renames = 0;
    -+		else if (!strcasecmp(value, "conflict"))
    ++		int boolval = git_parse_maybe_bool(value);
    ++		if (0 <= boolval) {
    ++			opt->detect_directory_renames = boolval ? 2 : 0;
    ++		} else if (!strcasecmp(value, "conflict")) {
     +			opt->detect_directory_renames = 1;
    -+		else {
    -+			error(_("Invalid value for merge.directoryRenames: %s"),
    -+			      value);
    -+			opt->detect_directory_renames = 1;
    -+		}
    ++		} /* avoid erroring on values from future versions of git */
     +		free(value);
     +	}
      	git_config(git_xmerge_config, NULL);
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 01/15] Use 'unsigned short' for mode, like diff_filespec does

[Elijah Newren]

struct diff_filespec defines mode to be an 'unsigned short'.  Several
other places in the API which we'd like to interact with using a
diff_filespec used a plain unsigned (or unsigned int).  This caused
problems when taking addresses, so switch to unsigned short.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 archive.c              | 2 +-
 blame.c                | 2 +-
 blame.h                | 2 +-
 builtin/rm.c           | 2 +-
 builtin/update-index.c | 2 +-
 cache.h                | 2 +-
 fsck.c                 | 2 +-
 line-log.c             | 2 +-
 match-trees.c          | 8 ++++----
 merge-recursive.c      | 6 +++---
 notes.c                | 2 +-
 sha1-name.c            | 2 +-
 tree-diff.c            | 2 +-
 tree-walk.c            | 6 +++---
 tree-walk.h            | 6 +++---
 15 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/archive.c b/archive.c
index 1f98324a93..92bc001545 100644
--- a/archive.c
+++ b/archive.c
@@ -415,7 +415,7 @@ static void parse_treeish_arg(const char **argv,
 
 	if (prefix) {
 		struct object_id tree_oid;
-		unsigned int mode;
+		unsigned short mode;
 		int err;
 
 		err = get_tree_entry(&tree->object.oid, prefix, &tree_oid,
diff --git a/blame.c b/blame.c
index 5c07dec190..326231476e 100644
--- a/blame.c
+++ b/blame.c
@@ -99,7 +99,7 @@ static void verify_working_tree_path(struct repository *r,
 	for (parents = work_tree->parents; parents; parents = parents->next) {
 		const struct object_id *commit_oid = &parents->item->object.oid;
 		struct object_id blob_oid;
-		unsigned mode;
+		unsigned short mode;
 
 		if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
 		    oid_object_info(r, &blob_oid, NULL) == OBJ_BLOB)
diff --git a/blame.h b/blame.h
index be3a895043..2a285eb027 100644
--- a/blame.h
+++ b/blame.h
@@ -52,7 +52,7 @@ struct blame_origin {
 	struct blame_entry *suspects;
 	mmfile_t file;
 	struct object_id blob_oid;
-	unsigned mode;
+	unsigned short mode;
 	/* guilty gets set when shipping any suspects to the final
 	 * blame list instead of other commits
 	 */
diff --git a/builtin/rm.c b/builtin/rm.c
index db85b33982..90cbe896c9 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -110,7 +110,7 @@ static int check_local_mod(struct object_id *head, int index_only)
 		const struct cache_entry *ce;
 		const char *name = list.entry[i].name;
 		struct object_id oid;
-		unsigned mode;
+		unsigned short mode;
 		int local_changes = 0;
 		int staged_changes = 0;
 
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 1b6c42f748..0baf51c316 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -597,7 +597,7 @@ static struct cache_entry *read_one_ent(const char *which,
 					struct object_id *ent, const char *path,
 					int namelen, int stage)
 {
-	unsigned mode;
+	unsigned short mode;
 	struct object_id oid;
 	struct cache_entry *ce;
 
diff --git a/cache.h b/cache.h
index ac92421f3a..851c3e6945 100644
--- a/cache.h
+++ b/cache.h
@@ -1331,7 +1331,7 @@ static inline int hex2chr(const char *s)
 #define FALLBACK_DEFAULT_ABBREV 7
 
 struct object_context {
-	unsigned mode;
+	unsigned short mode;
 	/*
 	 * symlink_path is only used by get_tree_entry_follow_symlinks,
 	 * and only for symlinks that point outside the repository.
diff --git a/fsck.c b/fsck.c
index 2260adb71e..4703f55561 100644
--- a/fsck.c
+++ b/fsck.c
@@ -604,7 +604,7 @@ static int fsck_tree(struct tree *item, struct fsck_options *options)
 	o_name = NULL;
 
 	while (desc.size) {
-		unsigned mode;
+		unsigned short mode;
 		const char *name;
 		const struct object_id *oid;
 
diff --git a/line-log.c b/line-log.c
index 24e21731c4..f743592bc0 100644
--- a/line-log.c
+++ b/line-log.c
@@ -498,7 +498,7 @@ static struct commit *check_single_commit(struct rev_info *revs)
 
 static void fill_blob_sha1(struct commit *commit, struct diff_filespec *spec)
 {
-	unsigned mode;
+	unsigned short mode;
 	struct object_id oid;
 
 	if (get_tree_entry(&commit->object.oid, spec->path, &oid, &mode))
diff --git a/match-trees.c b/match-trees.c
index ddc4d39845..9d1ec8d6b0 100644
--- a/match-trees.c
+++ b/match-trees.c
@@ -140,7 +140,7 @@ static void match_trees(const struct object_id *hash1,
 	while (one.size) {
 		const char *path;
 		const struct object_id *elem;
-		unsigned mode;
+		unsigned short mode;
 		int score;
 
 		elem = tree_entry_extract(&one, &path, &mode);
@@ -196,7 +196,7 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
 	rewrite_here = NULL;
 	while (desc.size) {
 		const char *name;
-		unsigned mode;
+		unsigned short mode;
 
 		tree_entry_extract(&desc, &name, &mode);
 		if (strlen(name) == toplen &&
@@ -285,7 +285,7 @@ void shift_tree(const struct object_id *hash1,
 
 	if (add_score < del_score) {
 		/* We need to pick a subtree of two */
-		unsigned mode;
+		unsigned short mode;
 
 		if (!*del_prefix)
 			return;
@@ -313,7 +313,7 @@ void shift_tree_by(const struct object_id *hash1,
 		   const char *shift_prefix)
 {
 	struct object_id sub1, sub2;
-	unsigned mode1, mode2;
+	unsigned short mode1, mode2;
 	unsigned candidate = 0;
 
 	/* Can hash2 be a tree at shift_prefix in tree hash1? */
diff --git a/merge-recursive.c b/merge-recursive.c
index 6c40c61c47..fcf37be2a7 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -214,7 +214,7 @@ struct rename_conflict_info {
  */
 struct stage_data {
 	struct {
-		unsigned mode;
+		unsigned short mode;
 		struct object_id oid;
 	} stages[4];
 	struct rename_conflict_info *rename_conflict_info;
@@ -482,7 +482,7 @@ static void get_files_dirs(struct merge_options *o, struct tree *tree)
 static int get_tree_entry_if_blob(const struct object_id *tree,
 				  const char *path,
 				  struct object_id *hashy,
-				  unsigned int *mode_o)
+				  unsigned short *mode_o)
 {
 	int ret;
 
@@ -1935,7 +1935,7 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 static int tree_has_path(struct tree *tree, const char *path)
 {
 	struct object_id hashy;
-	unsigned int mode_o;
+	unsigned short mode_o;
 
 	return !get_tree_entry(&tree->object.oid, path,
 			       &hashy, &mode_o);
diff --git a/notes.c b/notes.c
index 7f7cc4d511..ba4cae7851 100644
--- a/notes.c
+++ b/notes.c
@@ -986,7 +986,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 		combine_notes_fn combine_notes, int flags)
 {
 	struct object_id oid, object_oid;
-	unsigned mode;
+	unsigned short mode;
 	struct leaf_node root_tree;
 
 	if (!t)
diff --git a/sha1-name.c b/sha1-name.c
index 6dda2c16df..d4b3d01f3c 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -1577,7 +1577,7 @@ static void diagnose_invalid_oid_path(const char *prefix,
 				      int object_name_len)
 {
 	struct object_id oid;
-	unsigned mode;
+	unsigned short mode;
 
 	if (!prefix)
 		prefix = "";
diff --git a/tree-diff.c b/tree-diff.c
index e6d306f69f..f1f641eb6a 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -181,7 +181,7 @@ static struct combine_diff_path *emit_path(struct combine_diff_path *p,
 	struct tree_desc *t, struct tree_desc *tp,
 	int imin)
 {
-	unsigned mode;
+	unsigned short mode;
 	const char *path;
 	const struct object_id *oid;
 	int pathlen;
diff --git a/tree-walk.c b/tree-walk.c
index 1e4bbc8a0e..ec32a47b2e 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -500,7 +500,7 @@ struct dir_state {
 	struct object_id oid;
 };
 
-static int find_tree_entry(struct tree_desc *t, const char *name, struct object_id *result, unsigned *mode)
+static int find_tree_entry(struct tree_desc *t, const char *name, struct object_id *result, unsigned short *mode)
 {
 	int namelen = strlen(name);
 	while (t->size) {
@@ -535,7 +535,7 @@ static int find_tree_entry(struct tree_desc *t, const char *name, struct object_
 	return -1;
 }
 
-int get_tree_entry(const struct object_id *tree_oid, const char *name, struct object_id *oid, unsigned *mode)
+int get_tree_entry(const struct object_id *tree_oid, const char *name, struct object_id *oid, unsigned short *mode)
 {
 	int retval;
 	void *tree;
@@ -585,7 +585,7 @@ int get_tree_entry(const struct object_id *tree_oid, const char *name, struct ob
  * See the code for enum get_oid_result for a description of
  * the return values.
  */
-enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode)
+enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned short *mode)
 {
 	int retval = MISSING_OBJECT;
 	struct dir_state *parents = NULL;
diff --git a/tree-walk.h b/tree-walk.h
index 8225171866..3aa381b6a3 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -16,7 +16,7 @@ struct tree_desc {
 	unsigned int size;
 };
 
-static inline const struct object_id *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
+static inline const struct object_id *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned short *modep)
 {
 	*pathp = desc->entry.path;
 	*modep = desc->entry.mode;
@@ -51,7 +51,7 @@ struct traverse_info;
 typedef int (*traverse_callback_t)(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *);
 int traverse_trees(struct index_state *istate, int n, struct tree_desc *t, struct traverse_info *info);
 
-enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode);
+enum get_oid_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned short *mode);
 
 struct traverse_info {
 	const char *traverse_path;
@@ -66,7 +66,7 @@ struct traverse_info {
 	int show_all_errors;
 };
 
-int get_tree_entry(const struct object_id *, const char *, struct object_id *, unsigned *);
+int get_tree_entry(const struct object_id *, const char *, struct object_id *, unsigned short *);
 extern char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n);
 extern void setup_traverse_info(struct traverse_info *info, const char *base);
 
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 02/15] merge-recursive: rename merge_options argument from 'o' to 'opt'

[Elijah Newren]

The name 'o' was used for the merge_options struct pointer taken by many
functions, but in a few places it was named 'opt'.  Several functions
that didn't need merge_options instead used 'o' for a diff_filespec
argument or local.  Some functions needed both an inconsistently either
renamed the merge_options to 'opt' or the diff_filespec to 'one'.  I
want to remove the weird split in the codebase between using a
diff_filespec and a pair of (oid,mode) values in favor of using a
diff_filespec everywhere, but that dramatically increases the number of
cases where we want to use 'o' as a diff_filespec.  Rename the
merge_options argument to 'opt' to make room.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 984 +++++++++++++++++++++++-----------------------
 1 file changed, 492 insertions(+), 492 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index fcf37be2a7..09b76d596e 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -115,32 +115,32 @@ static void collision_init(struct hashmap *map)
 	hashmap_init(map, (hashmap_cmp_fn) collision_cmp, NULL, 0);
 }
 
-static void flush_output(struct merge_options *o)
+static void flush_output(struct merge_options *opt)
 {
-	if (o->buffer_output < 2 && o->obuf.len) {
-		fputs(o->obuf.buf, stdout);
-		strbuf_reset(&o->obuf);
+	if (opt->buffer_output < 2 && opt->obuf.len) {
+		fputs(opt->obuf.buf, stdout);
+		strbuf_reset(&opt->obuf);
 	}
 }
 
-static int err(struct merge_options *o, const char *err, ...)
+static int err(struct merge_options *opt, const char *err, ...)
 {
 	va_list params;
 
-	if (o->buffer_output < 2)
-		flush_output(o);
+	if (opt->buffer_output < 2)
+		flush_output(opt);
 	else {
-		strbuf_complete(&o->obuf, '\n');
-		strbuf_addstr(&o->obuf, "error: ");
+		strbuf_complete(&opt->obuf, '\n');
+		strbuf_addstr(&opt->obuf, "error: ");
 	}
 	va_start(params, err);
-	strbuf_vaddf(&o->obuf, err, params);
+	strbuf_vaddf(&opt->obuf, err, params);
 	va_end(params);
-	if (o->buffer_output > 1)
-		strbuf_addch(&o->obuf, '\n');
+	if (opt->buffer_output > 1)
+		strbuf_addch(&opt->obuf, '\n');
 	else {
-		error("%s", o->obuf.buf);
-		strbuf_reset(&o->obuf);
+		error("%s", opt->obuf.buf);
+		strbuf_reset(&opt->obuf);
 	}
 
 	return -1;
@@ -228,7 +228,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      const char *branch2,
 					      struct stage_data *dst_entry1,
 					      struct stage_data *dst_entry2,
-					      struct merge_options *o,
+					      struct merge_options *opt,
 					      struct stage_data *src_entry1,
 					      struct stage_data *src_entry2)
 {
@@ -239,15 +239,15 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 * When we have two renames involved, it's easiest to get the
 	 * correct things into stage 2 and 3, and to make sure that the
 	 * content merge puts HEAD before the other branch if we just
-	 * ensure that branch1 == o->branch1.  So, simply flip arguments
+	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (dst_entry2 && branch1 != o->branch1) {
+	if (dst_entry2 && branch1 != opt->branch1) {
 		setup_rename_conflict_info(rename_type,
 					   pair2,      pair1,
 					   branch2,    branch1,
 					   dst_entry2, dst_entry1,
-					   o,
+					   opt,
 					   src_entry2, src_entry1);
 		return;
 	}
@@ -276,7 +276,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 */
 	if (rename_type == RENAME_ADD ||
 	    rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage1 = o->branch1 == branch1 ? 3 : 2;
+		ostage1 = opt->branch1 == branch1 ? 3 : 2;
 
 		ci->ren1_other.path = pair1->one->path;
 		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
@@ -292,67 +292,67 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	}
 }
 
-static int show(struct merge_options *o, int v)
+static int show(struct merge_options *opt, int v)
 {
-	return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
+	return (!opt->call_depth && opt->verbosity >= v) || opt->verbosity >= 5;
 }
 
 __attribute__((format (printf, 3, 4)))
-static void output(struct merge_options *o, int v, const char *fmt, ...)
+static void output(struct merge_options *opt, int v, const char *fmt, ...)
 {
 	va_list ap;
 
-	if (!show(o, v))
+	if (!show(opt, v))
 		return;
 
-	strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
+	strbuf_addchars(&opt->obuf, ' ', opt->call_depth * 2);
 
 	va_start(ap, fmt);
-	strbuf_vaddf(&o->obuf, fmt, ap);
+	strbuf_vaddf(&opt->obuf, fmt, ap);
 	va_end(ap);
 
-	strbuf_addch(&o->obuf, '\n');
-	if (!o->buffer_output)
-		flush_output(o);
+	strbuf_addch(&opt->obuf, '\n');
+	if (!opt->buffer_output)
+		flush_output(opt);
 }
 
-static void output_commit_title(struct merge_options *o, struct commit *commit)
+static void output_commit_title(struct merge_options *opt, struct commit *commit)
 {
 	struct merge_remote_desc *desc;
 
-	strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
+	strbuf_addchars(&opt->obuf, ' ', opt->call_depth * 2);
 	desc = merge_remote_util(commit);
 	if (desc)
-		strbuf_addf(&o->obuf, "virtual %s\n", desc->name);
+		strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
 	else {
-		strbuf_add_unique_abbrev(&o->obuf, &commit->object.oid,
+		strbuf_add_unique_abbrev(&opt->obuf, &commit->object.oid,
 					 DEFAULT_ABBREV);
-		strbuf_addch(&o->obuf, ' ');
+		strbuf_addch(&opt->obuf, ' ');
 		if (parse_commit(commit) != 0)
-			strbuf_addstr(&o->obuf, _("(bad commit)\n"));
+			strbuf_addstr(&opt->obuf, _("(bad commit)\n"));
 		else {
 			const char *title;
 			const char *msg = get_commit_buffer(commit, NULL);
 			int len = find_commit_subject(msg, &title);
 			if (len)
-				strbuf_addf(&o->obuf, "%.*s\n", len, title);
+				strbuf_addf(&opt->obuf, "%.*s\n", len, title);
 			unuse_commit_buffer(commit, msg);
 		}
 	}
-	flush_output(o);
+	flush_output(opt);
 }
 
-static int add_cacheinfo(struct merge_options *o,
+static int add_cacheinfo(struct merge_options *opt,
 			 unsigned int mode, const struct object_id *oid,
 			 const char *path, int stage, int refresh, int options)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 	struct cache_entry *ce;
 	int ret;
 
 	ce = make_cache_entry(istate, mode, oid ? oid : &null_oid, path, stage, 0);
 	if (!ce)
-		return err(o, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
+		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
 	ret = add_index_entry(istate, ce, options);
 	if (refresh) {
@@ -361,7 +361,7 @@ static int add_cacheinfo(struct merge_options *o,
 		nce = refresh_cache_entry(istate, ce,
 					  CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 		if (!nce)
-			return err(o, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
+			return err(opt, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
 		if (nce != ce)
 			ret = add_index_entry(istate, nce, options);
 	}
@@ -374,7 +374,7 @@ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 	init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int unpack_trees_start(struct merge_options *o,
+static int unpack_trees_start(struct merge_options *opt,
 			      struct tree *common,
 			      struct tree *head,
 			      struct tree *merge)
@@ -383,49 +383,49 @@ static int unpack_trees_start(struct merge_options *o,
 	struct tree_desc t[3];
 	struct index_state tmp_index = { NULL };
 
-	memset(&o->unpack_opts, 0, sizeof(o->unpack_opts));
-	if (o->call_depth)
-		o->unpack_opts.index_only = 1;
+	memset(&opt->unpack_opts, 0, sizeof(opt->unpack_opts));
+	if (opt->call_depth)
+		opt->unpack_opts.index_only = 1;
 	else
-		o->unpack_opts.update = 1;
-	o->unpack_opts.merge = 1;
-	o->unpack_opts.head_idx = 2;
-	o->unpack_opts.fn = threeway_merge;
-	o->unpack_opts.src_index = o->repo->index;
-	o->unpack_opts.dst_index = &tmp_index;
-	o->unpack_opts.aggressive = !merge_detect_rename(o);
-	setup_unpack_trees_porcelain(&o->unpack_opts, "merge");
+		opt->unpack_opts.update = 1;
+	opt->unpack_opts.merge = 1;
+	opt->unpack_opts.head_idx = 2;
+	opt->unpack_opts.fn = threeway_merge;
+	opt->unpack_opts.src_index = opt->repo->index;
+	opt->unpack_opts.dst_index = &tmp_index;
+	opt->unpack_opts.aggressive = !merge_detect_rename(opt);
+	setup_unpack_trees_porcelain(&opt->unpack_opts, "merge");
 
 	init_tree_desc_from_tree(t+0, common);
 	init_tree_desc_from_tree(t+1, head);
 	init_tree_desc_from_tree(t+2, merge);
 
-	rc = unpack_trees(3, t, &o->unpack_opts);
-	cache_tree_free(&o->repo->index->cache_tree);
+	rc = unpack_trees(3, t, &opt->unpack_opts);
+	cache_tree_free(&opt->repo->index->cache_tree);
 
 	/*
-	 * Update o->repo->index to match the new results, AFTER saving a copy
-	 * in o->orig_index.  Update src_index to point to the saved copy.
+	 * Update opt->repo->index to match the new results, AFTER saving a copy
+	 * in opt->orig_index.  Update src_index to point to the saved copy.
 	 * (verify_uptodate() checks src_index, and the original index is
 	 * the one that had the necessary modification timestamps.)
 	 */
-	o->orig_index = *o->repo->index;
-	*o->repo->index = tmp_index;
-	o->unpack_opts.src_index = &o->orig_index;
+	opt->orig_index = *opt->repo->index;
+	*opt->repo->index = tmp_index;
+	opt->unpack_opts.src_index = &opt->orig_index;
 
 	return rc;
 }
 
-static void unpack_trees_finish(struct merge_options *o)
+static void unpack_trees_finish(struct merge_options *opt)
 {
-	discard_index(&o->orig_index);
-	clear_unpack_trees_porcelain(&o->unpack_opts);
+	discard_index(&opt->orig_index);
+	clear_unpack_trees_porcelain(&opt->unpack_opts);
 }
 
-struct tree *write_tree_from_memory(struct merge_options *o)
+struct tree *write_tree_from_memory(struct merge_options *opt)
 {
 	struct tree *result = NULL;
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 
 	if (unmerged_index(istate)) {
 		int i;
@@ -444,11 +444,11 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 
 	if (!cache_tree_fully_valid(istate->cache_tree) &&
 	    cache_tree_update(istate, 0) < 0) {
-		err(o, _("error building trees"));
+		err(opt, _("error building trees"));
 		return NULL;
 	}
 
-	result = lookup_tree(o->repo, &istate->cache_tree->oid);
+	result = lookup_tree(opt->repo, &istate->cache_tree->oid);
 
 	return result;
 }
@@ -459,24 +459,24 @@ static int save_files_dirs(const struct object_id *oid,
 {
 	struct path_hashmap_entry *entry;
 	int baselen = base->len;
-	struct merge_options *o = context;
+	struct merge_options *opt = context;
 
 	strbuf_addstr(base, path);
 
 	FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
 	hashmap_entry_init(entry, path_hash(entry->path));
-	hashmap_add(&o->current_file_dir_set, entry);
+	hashmap_add(&opt->current_file_dir_set, entry);
 
 	strbuf_setlen(base, baselen);
 	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 }
 
-static void get_files_dirs(struct merge_options *o, struct tree *tree)
+static void get_files_dirs(struct merge_options *opt, struct tree *tree)
 {
 	struct pathspec match_all;
 	memset(&match_all, 0, sizeof(match_all));
 	read_tree_recursive(the_repository, tree, "", 0, 0,
-			    &match_all, save_files_dirs, o);
+			    &match_all, save_files_dirs, opt);
 }
 
 static int get_tree_entry_if_blob(const struct object_id *tree,
@@ -573,7 +573,7 @@ static int string_list_df_name_compare(const char *one, const char *two)
 	return onelen - twolen;
 }
 
-static void record_df_conflict_files(struct merge_options *o,
+static void record_df_conflict_files(struct merge_options *opt,
 				     struct string_list *entries)
 {
 	/* If there is a D/F conflict and the file for such a conflict
@@ -598,7 +598,7 @@ static void record_df_conflict_files(struct merge_options *o,
 	 * If we're merging merge-bases, we don't want to bother with
 	 * any working directory changes.
 	 */
-	if (o->call_depth)
+	if (opt->call_depth)
 		return;
 
 	/* Ensure D/F conflicts are adjacent in the entries list. */
@@ -610,7 +610,7 @@ static void record_df_conflict_files(struct merge_options *o,
 	df_sorted_entries.cmp = string_list_df_name_compare;
 	string_list_sort(&df_sorted_entries);
 
-	string_list_clear(&o->df_conflict_file_set, 1);
+	string_list_clear(&opt->df_conflict_file_set, 1);
 	for (i = 0; i < df_sorted_entries.nr; i++) {
 		const char *path = df_sorted_entries.items[i].string;
 		int len = strlen(path);
@@ -626,7 +626,7 @@ static void record_df_conflict_files(struct merge_options *o,
 		    len > last_len &&
 		    memcmp(path, last_file, last_len) == 0 &&
 		    path[last_len] == '/') {
-			string_list_insert(&o->df_conflict_file_set, last_file);
+			string_list_insert(&opt->df_conflict_file_set, last_file);
 		}
 
 		/*
@@ -717,20 +717,20 @@ static void update_entry(struct stage_data *entry,
 	oidcpy(&entry->stages[3].oid, &b->oid);
 }
 
-static int remove_file(struct merge_options *o, int clean,
+static int remove_file(struct merge_options *opt, int clean,
 		       const char *path, int no_wd)
 {
-	int update_cache = o->call_depth || clean;
-	int update_working_directory = !o->call_depth && !no_wd;
+	int update_cache = opt->call_depth || clean;
+	int update_working_directory = !opt->call_depth && !no_wd;
 
 	if (update_cache) {
-		if (remove_file_from_index(o->repo->index, path))
+		if (remove_file_from_index(opt->repo->index, path))
 			return -1;
 	}
 	if (update_working_directory) {
 		if (ignore_case) {
 			struct cache_entry *ce;
-			ce = index_file_exists(o->repo->index, path, strlen(path),
+			ce = index_file_exists(opt->repo->index, path, strlen(path),
 					       ignore_case);
 			if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
 				return 0;
@@ -751,7 +751,7 @@ static void add_flattened_path(struct strbuf *out, const char *s)
 			out->buf[i] = '_';
 }
 
-static char *unique_path(struct merge_options *o, const char *path, const char *branch)
+static char *unique_path(struct merge_options *opt, const char *path, const char *branch)
 {
 	struct path_hashmap_entry *entry;
 	struct strbuf newpath = STRBUF_INIT;
@@ -762,16 +762,16 @@ static char *unique_path(struct merge_options *o, const char *path, const char *
 	add_flattened_path(&newpath, branch);
 
 	base_len = newpath.len;
-	while (hashmap_get_from_hash(&o->current_file_dir_set,
+	while (hashmap_get_from_hash(&opt->current_file_dir_set,
 				     path_hash(newpath.buf), newpath.buf) ||
-	       (!o->call_depth && file_exists(newpath.buf))) {
+	       (!opt->call_depth && file_exists(newpath.buf))) {
 		strbuf_setlen(&newpath, base_len);
 		strbuf_addf(&newpath, "_%d", suffix++);
 	}
 
 	FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
 	hashmap_entry_init(entry, path_hash(entry->path));
-	hashmap_add(&o->current_file_dir_set, entry);
+	hashmap_add(&opt->current_file_dir_set, entry);
 	return strbuf_detach(&newpath, NULL);
 }
 
@@ -810,10 +810,10 @@ static int dir_in_way(struct index_state *istate, const char *path,
  * Returns whether path was tracked in the index before the merge started,
  * and its oid and mode match the specified values
  */
-static int was_tracked_and_matches(struct merge_options *o, const char *path,
+static int was_tracked_and_matches(struct merge_options *opt, const char *path,
 				   const struct object_id *oid, unsigned mode)
 {
-	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 	struct cache_entry *ce;
 
 	if (0 > pos)
@@ -821,16 +821,16 @@ static int was_tracked_and_matches(struct merge_options *o, const char *path,
 		return 0;
 
 	/* See if the file we were tracking before matches */
-	ce = o->orig_index.cache[pos];
+	ce = opt->orig_index.cache[pos];
 	return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
 }
 
 /*
  * Returns whether path was tracked in the index before the merge started
  */
-static int was_tracked(struct merge_options *o, const char *path)
+static int was_tracked(struct merge_options *opt, const char *path)
 {
-	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 
 	if (0 <= pos)
 		/* we were tracking this path before the merge */
@@ -839,13 +839,13 @@ static int was_tracked(struct merge_options *o, const char *path)
 	return 0;
 }
 
-static int would_lose_untracked(struct merge_options *o, const char *path)
+static int would_lose_untracked(struct merge_options *opt, const char *path)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 
 	/*
 	 * This may look like it can be simplified to:
-	 *   return !was_tracked(o, path) && file_exists(path)
+	 *   return !was_tracked(opt, path) && file_exists(path)
 	 * but it can't.  This function needs to know whether path was in
 	 * the working tree due to EITHER having been tracked in the index
 	 * before the merge OR having been put into the working copy and
@@ -882,38 +882,38 @@ static int would_lose_untracked(struct merge_options *o, const char *path)
 	return file_exists(path);
 }
 
-static int was_dirty(struct merge_options *o, const char *path)
+static int was_dirty(struct merge_options *opt, const char *path)
 {
 	struct cache_entry *ce;
 	int dirty = 1;
 
-	if (o->call_depth || !was_tracked(o, path))
+	if (opt->call_depth || !was_tracked(opt, path))
 		return !dirty;
 
-	ce = index_file_exists(o->unpack_opts.src_index,
+	ce = index_file_exists(opt->unpack_opts.src_index,
 			       path, strlen(path), ignore_case);
-	dirty = verify_uptodate(ce, &o->unpack_opts) != 0;
+	dirty = verify_uptodate(ce, &opt->unpack_opts) != 0;
 	return dirty;
 }
 
-static int make_room_for_path(struct merge_options *o, const char *path)
+static int make_room_for_path(struct merge_options *opt, const char *path)
 {
 	int status, i;
 	const char *msg = _("failed to create path '%s'%s");
 
 	/* Unlink any D/F conflict files that are in the way */
-	for (i = 0; i < o->df_conflict_file_set.nr; i++) {
-		const char *df_path = o->df_conflict_file_set.items[i].string;
+	for (i = 0; i < opt->df_conflict_file_set.nr; i++) {
+		const char *df_path = opt->df_conflict_file_set.items[i].string;
 		size_t pathlen = strlen(path);
 		size_t df_pathlen = strlen(df_path);
 		if (df_pathlen < pathlen &&
 		    path[df_pathlen] == '/' &&
 		    strncmp(path, df_path, df_pathlen) == 0) {
-			output(o, 3,
+			output(opt, 3,
 			       _("Removing %s to make room for subdirectory\n"),
 			       df_path);
 			unlink(df_path);
-			unsorted_string_list_delete_item(&o->df_conflict_file_set,
+			unsorted_string_list_delete_item(&opt->df_conflict_file_set,
 							 i, 0);
 			break;
 		}
@@ -924,16 +924,16 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	if (status) {
 		if (status == SCLD_EXISTS)
 			/* something else exists */
-			return err(o, msg, path, _(": perhaps a D/F conflict?"));
-		return err(o, msg, path, "");
+			return err(opt, msg, path, _(": perhaps a D/F conflict?"));
+		return err(opt, msg, path, "");
 	}
 
 	/*
 	 * Do not unlink a file in the work tree if we are not
 	 * tracking it.
 	 */
-	if (would_lose_untracked(o, path))
-		return err(o, _("refusing to lose untracked file at '%s'"),
+	if (would_lose_untracked(opt, path))
+		return err(opt, _("refusing to lose untracked file at '%s'"),
 			   path);
 
 	/* Successful unlink is good.. */
@@ -943,10 +943,10 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	if (errno == ENOENT)
 		return 0;
 	/* .. but not some other error (who really cares what?) */
-	return err(o, msg, path, _(": perhaps a D/F conflict?"));
+	return err(opt, msg, path, _(": perhaps a D/F conflict?"));
 }
 
-static int update_file_flags(struct merge_options *o,
+static int update_file_flags(struct merge_options *opt,
 			     const struct object_id *oid,
 			     unsigned mode,
 			     const char *path,
@@ -955,7 +955,7 @@ static int update_file_flags(struct merge_options *o,
 {
 	int ret = 0;
 
-	if (o->call_depth)
+	if (opt->call_depth)
 		update_wd = 0;
 
 	if (update_wd) {
@@ -975,21 +975,21 @@ static int update_file_flags(struct merge_options *o,
 
 		buf = read_object_file(oid, &type, &size);
 		if (!buf)
-			return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
+			return err(opt, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
 		if (type != OBJ_BLOB) {
-			ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
+			ret = err(opt, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
 			goto free_buf;
 		}
 		if (S_ISREG(mode)) {
 			struct strbuf strbuf = STRBUF_INIT;
-			if (convert_to_working_tree(o->repo->index, path, buf, size, &strbuf)) {
+			if (convert_to_working_tree(opt->repo->index, path, buf, size, &strbuf)) {
 				free(buf);
 				size = strbuf.len;
 				buf = strbuf_detach(&strbuf, NULL);
 			}
 		}
 
-		if (make_room_for_path(o, path) < 0) {
+		if (make_room_for_path(opt, path) < 0) {
 			update_wd = 0;
 			goto free_buf;
 		}
@@ -1001,7 +1001,7 @@ static int update_file_flags(struct merge_options *o,
 				mode = 0666;
 			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 			if (fd < 0) {
-				ret = err(o, _("failed to open '%s': %s"),
+				ret = err(opt, _("failed to open '%s': %s"),
 					  path, strerror(errno));
 				goto free_buf;
 			}
@@ -1012,11 +1012,11 @@ static int update_file_flags(struct merge_options *o,
 			safe_create_leading_directories_const(path);
 			unlink(path);
 			if (symlink(lnk, path))
-				ret = err(o, _("failed to symlink '%s': %s"),
+				ret = err(opt, _("failed to symlink '%s': %s"),
 					  path, strerror(errno));
 			free(lnk);
 		} else
-			ret = err(o,
+			ret = err(opt,
 				  _("do not know what to do with %06o %s '%s'"),
 				  mode, oid_to_hex(oid), path);
 	free_buf:
@@ -1024,19 +1024,19 @@ static int update_file_flags(struct merge_options *o,
 	}
 update_index:
 	if (!ret && update_cache)
-		if (add_cacheinfo(o, mode, oid, path, 0, update_wd,
+		if (add_cacheinfo(opt, mode, oid, path, 0, update_wd,
 				  ADD_CACHE_OK_TO_ADD))
 			return -1;
 	return ret;
 }
 
-static int update_file(struct merge_options *o,
+static int update_file(struct merge_options *opt,
 		       int clean,
 		       const struct object_id *oid,
 		       unsigned mode,
 		       const char *path)
 {
-	return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
+	return update_file_flags(opt, oid, mode, path, opt->call_depth || clean, !opt->call_depth);
 }
 
 /* Low level file merging, update and removal */
@@ -1048,7 +1048,7 @@ struct merge_file_info {
 		 merge:1;
 };
 
-static int merge_3way(struct merge_options *o,
+static int merge_3way(struct merge_options *opt,
 		      mmbuffer_t *result_buf,
 		      const struct diff_filespec *one,
 		      const struct diff_filespec *a,
@@ -1062,15 +1062,15 @@ static int merge_3way(struct merge_options *o,
 	char *base_name, *name1, *name2;
 	int merge_status;
 
-	ll_opts.renormalize = o->renormalize;
+	ll_opts.renormalize = opt->renormalize;
 	ll_opts.extra_marker_size = extra_marker_size;
-	ll_opts.xdl_opts = o->xdl_opts;
+	ll_opts.xdl_opts = opt->xdl_opts;
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		ll_opts.virtual_ancestor = 1;
 		ll_opts.variant = 0;
 	} else {
-		switch (o->recursive_variant) {
+		switch (opt->recursive_variant) {
 		case MERGE_RECURSIVE_OURS:
 			ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 			break;
@@ -1084,14 +1084,14 @@ static int merge_3way(struct merge_options *o,
 	}
 
 	if (strcmp(a->path, b->path) ||
-	    (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
-		base_name = o->ancestor == NULL ? NULL :
-			mkpathdup("%s:%s", o->ancestor, one->path);
+	    (opt->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
+		base_name = opt->ancestor == NULL ? NULL :
+			mkpathdup("%s:%s", opt->ancestor, one->path);
 		name1 = mkpathdup("%s:%s", branch1, a->path);
 		name2 = mkpathdup("%s:%s", branch2, b->path);
 	} else {
-		base_name = o->ancestor == NULL ? NULL :
-			mkpathdup("%s", o->ancestor);
+		base_name = opt->ancestor == NULL ? NULL :
+			mkpathdup("%s", opt->ancestor);
 		name1 = mkpathdup("%s", branch1);
 		name2 = mkpathdup("%s", branch2);
 	}
@@ -1102,7 +1102,7 @@ static int merge_3way(struct merge_options *o,
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
-				o->repo->index, &ll_opts);
+				opt->repo->index, &ll_opts);
 
 	free(base_name);
 	free(name1);
@@ -1184,7 +1184,7 @@ static void print_commit(struct commit *commit)
 	strbuf_release(&sb);
 }
 
-static int merge_submodule(struct merge_options *o,
+static int merge_submodule(struct merge_options *opt,
 			   struct object_id *result, const char *path,
 			   const struct object_id *base, const struct object_id *a,
 			   const struct object_id *b)
@@ -1194,7 +1194,7 @@ static int merge_submodule(struct merge_options *o,
 	struct object_array merges;
 
 	int i;
-	int search = !o->call_depth;
+	int search = !opt->call_depth;
 
 	/* store a in result in case we fail */
 	oidcpy(result, a);
@@ -1208,32 +1208,32 @@ static int merge_submodule(struct merge_options *o,
 		return 0;
 
 	if (add_submodule_odb(path)) {
-		output(o, 1, _("Failed to merge submodule %s (not checked out)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
 		return 0;
 	}
 
-	if (!(commit_base = lookup_commit_reference(o->repo, base)) ||
-	    !(commit_a = lookup_commit_reference(o->repo, a)) ||
-	    !(commit_b = lookup_commit_reference(o->repo, b))) {
-		output(o, 1, _("Failed to merge submodule %s (commits not present)"), path);
+	if (!(commit_base = lookup_commit_reference(opt->repo, base)) ||
+	    !(commit_a = lookup_commit_reference(opt->repo, a)) ||
+	    !(commit_b = lookup_commit_reference(opt->repo, b))) {
+		output(opt, 1, _("Failed to merge submodule %s (commits not present)"), path);
 		return 0;
 	}
 
 	/* check whether both changes are forward */
 	if (!in_merge_bases(commit_base, commit_a) ||
 	    !in_merge_bases(commit_base, commit_b)) {
-		output(o, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
 		return 0;
 	}
 
 	/* Case #1: a is contained in b or vice versa */
 	if (in_merge_bases(commit_a, commit_b)) {
 		oidcpy(result, b);
-		if (show(o, 3)) {
-			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(o, commit_b);
-		} else if (show(o, 2))
-			output(o, 2, _("Fast-forwarding submodule %s"), path);
+		if (show(opt, 3)) {
+			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+			output_commit_title(opt, commit_b);
+		} else if (show(opt, 2))
+			output(opt, 2, _("Fast-forwarding submodule %s"), path);
 		else
 			; /* no output */
 
@@ -1241,11 +1241,11 @@ static int merge_submodule(struct merge_options *o,
 	}
 	if (in_merge_bases(commit_b, commit_a)) {
 		oidcpy(result, a);
-		if (show(o, 3)) {
-			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(o, commit_a);
-		} else if (show(o, 2))
-			output(o, 2, _("Fast-forwarding submodule %s"), path);
+		if (show(opt, 3)) {
+			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+			output_commit_title(opt, commit_a);
+		} else if (show(opt, 2))
+			output(opt, 2, _("Fast-forwarding submodule %s"), path);
 		else
 			; /* no output */
 
@@ -1264,18 +1264,18 @@ static int merge_submodule(struct merge_options *o,
 		return 0;
 
 	/* find commit which merges them */
-	parent_count = find_first_merges(o->repo, &merges, path,
+	parent_count = find_first_merges(opt->repo, &merges, path,
 					 commit_a, commit_b);
 	switch (parent_count) {
 	case 0:
-		output(o, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
 		break;
 
 	case 1:
-		output(o, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
-		output(o, 2, _("Found a possible merge resolution for the submodule:\n"));
+		output(opt, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
+		output(opt, 2, _("Found a possible merge resolution for the submodule:\n"));
 		print_commit((struct commit *) merges.objects[0].item);
-		output(o, 2, _(
+		output(opt, 2, _(
 		       "If this is correct simply add it to the index "
 		       "for example\n"
 		       "by using:\n\n"
@@ -1285,7 +1285,7 @@ static int merge_submodule(struct merge_options *o,
 		break;
 
 	default:
-		output(o, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
 		for (i = 0; i < merges.nr; i++)
 			print_commit((struct commit *) merges.objects[i].item);
 	}
@@ -1294,7 +1294,7 @@ static int merge_submodule(struct merge_options *o,
 	return 0;
 }
 
-static int merge_mode_and_contents(struct merge_options *o,
+static int merge_mode_and_contents(struct merge_options *opt,
 				   const struct diff_filespec *one,
 				   const struct diff_filespec *a,
 				   const struct diff_filespec *b,
@@ -1304,13 +1304,13 @@ static int merge_mode_and_contents(struct merge_options *o,
 				   const int extra_marker_size,
 				   struct merge_file_info *result)
 {
-	if (o->branch1 != branch1) {
+	if (opt->branch1 != branch1) {
 		/*
 		 * It's weird getting a reverse merge with HEAD on the bottom
 		 * side of the conflict markers and the other branch on the
 		 * top.  Fix that.
 		 */
-		return merge_mode_and_contents(o, one, b, a,
+		return merge_mode_and_contents(opt, one, b, a,
 					       filename,
 					       branch2, branch1,
 					       extra_marker_size, result);
@@ -1353,17 +1353,17 @@ static int merge_mode_and_contents(struct merge_options *o,
 			mmbuffer_t result_buf;
 			int ret = 0, merge_status;
 
-			merge_status = merge_3way(o, &result_buf, one, a, b,
+			merge_status = merge_3way(opt, &result_buf, one, a, b,
 						  branch1, branch2,
 						  extra_marker_size);
 
 			if ((merge_status < 0) || !result_buf.ptr)
-				ret = err(o, _("Failed to execute internal merge"));
+				ret = err(opt, _("Failed to execute internal merge"));
 
 			if (!ret &&
 			    write_object_file(result_buf.ptr, result_buf.size,
 					      blob_type, &result->oid))
-				ret = err(o, _("Unable to add %s to database"),
+				ret = err(opt, _("Unable to add %s to database"),
 					  a->path);
 
 			free(result_buf.ptr);
@@ -1371,13 +1371,13 @@ static int merge_mode_and_contents(struct merge_options *o,
 				return ret;
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(o, &result->oid,
+			result->clean = merge_submodule(opt, &result->oid,
 							one->path,
 							&one->oid,
 							&a->oid,
 							&b->oid);
 		} else if (S_ISLNK(a->mode)) {
-			switch (o->recursive_variant) {
+			switch (opt->recursive_variant) {
 			case MERGE_RECURSIVE_NORMAL:
 				oidcpy(&result->oid, &a->oid);
 				if (!oid_eq(&a->oid, &b->oid))
@@ -1395,12 +1395,12 @@ static int merge_mode_and_contents(struct merge_options *o,
 	}
 
 	if (result->merge)
-		output(o, 2, _("Auto-merging %s"), filename);
+		output(opt, 2, _("Auto-merging %s"), filename);
 
 	return 0;
 }
 
-static int handle_rename_via_dir(struct merge_options *o,
+static int handle_rename_via_dir(struct merge_options *opt,
 				 struct diff_filepair *pair,
 				 const char *rename_branch)
 {
@@ -1412,10 +1412,10 @@ static int handle_rename_via_dir(struct merge_options *o,
 	 */
 	const struct diff_filespec *dest = pair->two;
 
-	if (!o->call_depth && would_lose_untracked(o, dest->path)) {
-		char *alt_path = unique_path(o, dest->path, rename_branch);
+	if (!opt->call_depth && would_lose_untracked(opt, dest->path)) {
+		char *alt_path = unique_path(opt, dest->path, rename_branch);
 
-		output(o, 1, _("Error: Refusing to lose untracked file at %s; "
+		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
 			       "writing to %s instead."),
 		       dest->path, alt_path);
 		/*
@@ -1423,21 +1423,21 @@ static int handle_rename_via_dir(struct merge_options *o,
 		 * index.  Instead, write to dest->path for the index but
 		 * only at the higher appropriate stage.
 		 */
-		if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
+		if (update_file(opt, 0, &dest->oid, dest->mode, alt_path))
 			return -1;
 		free(alt_path);
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		return update_stages(opt, dest->path, NULL,
+				     rename_branch == opt->branch1 ? dest : NULL,
+				     rename_branch == opt->branch1 ? NULL : dest);
 	}
 
 	/* Update dest->path both in index and in worktree */
-	if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
+	if (update_file(opt, 1, &dest->oid, dest->mode, dest->path))
 		return -1;
 	return 0;
 }
 
-static int handle_change_delete(struct merge_options *o,
+static int handle_change_delete(struct merge_options *opt,
 				const char *path, const char *old_path,
 				const struct object_id *o_oid, int o_mode,
 				const struct object_id *changed_oid,
@@ -1450,20 +1450,20 @@ static int handle_change_delete(struct merge_options *o,
 	const char *update_path = path;
 	int ret = 0;
 
-	if (dir_in_way(o->repo->index, path, !o->call_depth, 0) ||
-	    (!o->call_depth && would_lose_untracked(o, path))) {
-		update_path = alt_path = unique_path(o, path, change_branch);
+	if (dir_in_way(opt->repo->index, path, !opt->call_depth, 0) ||
+	    (!opt->call_depth && would_lose_untracked(opt, path))) {
+		update_path = alt_path = unique_path(opt, path, change_branch);
 	}
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		/*
 		 * We cannot arbitrarily accept either a_sha or b_sha as
 		 * correct; since there is no true "middle point" between
 		 * them, simply reuse the base version for virtual merge base.
 		 */
-		ret = remove_file_from_index(o->repo->index, path);
+		ret = remove_file_from_index(opt->repo->index, path);
 		if (!ret)
-			ret = update_file(o, 0, o_oid, o_mode, update_path);
+			ret = update_file(opt, 0, o_oid, o_mode, update_path);
 	} else {
 		/*
 		 * Despite the four nearly duplicate messages and argument
@@ -1482,24 +1482,24 @@ static int handle_change_delete(struct merge_options *o,
 		 */
 		if (!alt_path) {
 			if (!old_path) {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s in %s. Version %s of %s left in tree."),
 				       change, path, delete_branch, change_past,
 				       change_branch, change_branch, path);
 			} else {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s to %s in %s. Version %s of %s left in tree."),
 				       change, old_path, delete_branch, change_past, path,
 				       change_branch, change_branch, path);
 			}
 		} else {
 			if (!old_path) {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s in %s. Version %s of %s left in tree at %s."),
 				       change, path, delete_branch, change_past,
 				       change_branch, change_branch, path, alt_path);
 			} else {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
 				       "and %s to %s in %s. Version %s of %s left in tree at %s."),
 				       change, old_path, delete_branch, change_past, path,
 				       change_branch, change_branch, path, alt_path);
@@ -1507,19 +1507,19 @@ static int handle_change_delete(struct merge_options *o,
 		}
 		/*
 		 * No need to call update_file() on path when change_branch ==
-		 * o->branch1 && !alt_path, since that would needlessly touch
+		 * opt->branch1 && !alt_path, since that would needlessly touch
 		 * path.  We could call update_file_flags() with update_cache=0
 		 * and update_wd=0, but that's a no-op.
 		 */
-		if (change_branch != o->branch1 || alt_path)
-			ret = update_file(o, 0, changed_oid, changed_mode, update_path);
+		if (change_branch != opt->branch1 || alt_path)
+			ret = update_file(opt, 0, changed_oid, changed_mode, update_path);
 	}
 	free(alt_path);
 
 	return ret;
 }
 
-static int handle_rename_delete(struct merge_options *o,
+static int handle_rename_delete(struct merge_options *opt,
 				struct diff_filepair *pair,
 				const char *rename_branch,
 				const char *delete_branch)
@@ -1527,21 +1527,21 @@ static int handle_rename_delete(struct merge_options *o,
 	const struct diff_filespec *orig = pair->one;
 	const struct diff_filespec *dest = pair->two;
 
-	if (handle_change_delete(o,
-				 o->call_depth ? orig->path : dest->path,
-				 o->call_depth ? NULL : orig->path,
+	if (handle_change_delete(opt,
+				 opt->call_depth ? orig->path : dest->path,
+				 opt->call_depth ? NULL : orig->path,
 				 &orig->oid, orig->mode,
 				 &dest->oid, dest->mode,
 				 rename_branch, delete_branch,
 				 _("rename"), _("renamed")))
 		return -1;
 
-	if (o->call_depth)
-		return remove_file_from_index(o->repo->index, dest->path);
+	if (opt->call_depth)
+		return remove_file_from_index(opt->repo->index, dest->path);
 	else
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		return update_stages(opt, dest->path, NULL,
+				     rename_branch == opt->branch1 ? dest : NULL,
+				     rename_branch == opt->branch1 ? NULL : dest);
 }
 
 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
@@ -1557,7 +1557,7 @@ static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
 	return target;
 }
 
-static int handle_file_collision(struct merge_options *o,
+static int handle_file_collision(struct merge_options *opt,
 				 const char *collide_path,
 				 const char *prev_path1,
 				 const char *prev_path2,
@@ -1575,11 +1575,11 @@ static int handle_file_collision(struct merge_options *o,
 	/*
 	 * It's easiest to get the correct things into stage 2 and 3, and
 	 * to make sure that the content merge puts HEAD before the other
-	 * branch if we just ensure that branch1 == o->branch1.  So, simply
+	 * branch if we just ensure that branch1 == opt->branch1.  So, simply
 	 * flip arguments around if we don't have that.
 	 */
-	if (branch1 != o->branch1) {
-		return handle_file_collision(o, collide_path,
+	if (branch1 != opt->branch1) {
+		return handle_file_collision(opt, collide_path,
 					     prev_path2, prev_path1,
 					     branch2, branch1,
 					     b_oid, b_mode,
@@ -1589,60 +1589,60 @@ static int handle_file_collision(struct merge_options *o,
 	/*
 	 * In the recursive case, we just opt to undo renames
 	 */
-	if (o->call_depth && (prev_path1 || prev_path2)) {
+	if (opt->call_depth && (prev_path1 || prev_path2)) {
 		/* Put first file (a_oid, a_mode) in its original spot */
 		if (prev_path1) {
-			if (update_file(o, 1, a_oid, a_mode, prev_path1))
+			if (update_file(opt, 1, a_oid, a_mode, prev_path1))
 				return -1;
 		} else {
-			if (update_file(o, 1, a_oid, a_mode, collide_path))
+			if (update_file(opt, 1, a_oid, a_mode, collide_path))
 				return -1;
 		}
 
 		/* Put second file (b_oid, b_mode) in its original spot */
 		if (prev_path2) {
-			if (update_file(o, 1, b_oid, b_mode, prev_path2))
+			if (update_file(opt, 1, b_oid, b_mode, prev_path2))
 				return -1;
 		} else {
-			if (update_file(o, 1, b_oid, b_mode, collide_path))
+			if (update_file(opt, 1, b_oid, b_mode, collide_path))
 				return -1;
 		}
 
 		/* Don't leave something at collision path if unrenaming both */
 		if (prev_path1 && prev_path2)
-			remove_file(o, 1, collide_path, 0);
+			remove_file(opt, 1, collide_path, 0);
 
 		return 0;
 	}
 
 	/* Remove rename sources if rename/add or rename/rename(2to1) */
 	if (prev_path1)
-		remove_file(o, 1, prev_path1,
-			    o->call_depth || would_lose_untracked(o, prev_path1));
+		remove_file(opt, 1, prev_path1,
+			    opt->call_depth || would_lose_untracked(opt, prev_path1));
 	if (prev_path2)
-		remove_file(o, 1, prev_path2,
-			    o->call_depth || would_lose_untracked(o, prev_path2));
+		remove_file(opt, 1, prev_path2,
+			    opt->call_depth || would_lose_untracked(opt, prev_path2));
 
 	/*
 	 * Remove the collision path, if it wouldn't cause dirty contents
 	 * or an untracked file to get lost.  We'll either overwrite with
 	 * merged contents, or just write out to differently named files.
 	 */
-	if (was_dirty(o, collide_path)) {
-		output(o, 1, _("Refusing to lose dirty file at %s"),
+	if (was_dirty(opt, collide_path)) {
+		output(opt, 1, _("Refusing to lose dirty file at %s"),
 		       collide_path);
-		update_path = alt_path = unique_path(o, collide_path, "merged");
-	} else if (would_lose_untracked(o, collide_path)) {
+		update_path = alt_path = unique_path(opt, collide_path, "merged");
+	} else if (would_lose_untracked(opt, collide_path)) {
 		/*
 		 * Only way we get here is if both renames were from
 		 * a directory rename AND user had an untracked file
 		 * at the location where both files end up after the
 		 * two directory renames.  See testcase 10d of t6043.
 		 */
-		output(o, 1, _("Refusing to lose untracked file at "
+		output(opt, 1, _("Refusing to lose untracked file at "
 			       "%s, even though it's in the way."),
 		       collide_path);
-		update_path = alt_path = unique_path(o, collide_path, "merged");
+		update_path = alt_path = unique_path(opt, collide_path, "merged");
 	} else {
 		/*
 		 * FIXME: It's possible that the two files are identical
@@ -1654,7 +1654,7 @@ static int handle_file_collision(struct merge_options *o,
 		 * merge-recursive interoperate anyway, so punting for
 		 * now...
 		 */
-		remove_file(o, 0, collide_path, 0);
+		remove_file(opt, 0, collide_path, 0);
 	}
 
 	/* Store things in diff_filespecs for functions that need it */
@@ -1670,14 +1670,14 @@ static int handle_file_collision(struct merge_options *o,
 	b.mode = b_mode;
 	b.oid_valid = 1;
 
-	if (merge_mode_and_contents(o, &null, &a, &b, collide_path,
-				    branch1, branch2, o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, &null, &a, &b, collide_path,
+				    branch1, branch2, opt->call_depth * 2, &mfi))
 		return -1;
 	mfi.clean &= !alt_path;
-	if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, update_path))
+	if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, update_path))
 		return -1;
-	if (!mfi.clean && !o->call_depth &&
-	    update_stages(o, collide_path, NULL, &a, &b))
+	if (!mfi.clean && !opt->call_depth &&
+	    update_stages(opt, collide_path, NULL, &a, &b))
 		return -1;
 	free(alt_path);
 	/*
@@ -1690,7 +1690,7 @@ static int handle_file_collision(struct merge_options *o,
 	return mfi.clean;
 }
 
-static int handle_rename_add(struct merge_options *o,
+static int handle_rename_add(struct merge_options *opt,
 			     struct rename_conflict_info *ci)
 {
 	/* a was renamed to c, and a separate c was added. */
@@ -1700,21 +1700,21 @@ static int handle_rename_add(struct merge_options *o,
 	char *prev_path_desc;
 	struct merge_file_info mfi;
 
-	int other_stage = (ci->branch1 == o->branch1 ? 3 : 2);
+	int other_stage = (ci->branch1 == opt->branch1 ? 3 : 2);
 
-	output(o, 1, _("CONFLICT (rename/add): "
+	output(opt, 1, _("CONFLICT (rename/add): "
 	       "Rename %s->%s in %s.  Added %s in %s"),
 	       a->path, c->path, ci->branch1,
 	       c->path, ci->branch2);
 
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(o, a, c, &ci->ren1_other, prev_path_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, a, c, &ci->ren1_other, prev_path_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi))
 		return -1;
 	free(prev_path_desc);
 
-	return handle_file_collision(o,
+	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
 				     ci->branch1, ci->branch2,
 				     &mfi.oid, mfi.mode,
@@ -1722,20 +1722,20 @@ static int handle_rename_add(struct merge_options *o,
 				     ci->dst_entry1->stages[other_stage].mode);
 }
 
-static char *find_path_for_conflict(struct merge_options *o,
+static char *find_path_for_conflict(struct merge_options *opt,
 				    const char *path,
 				    const char *branch1,
 				    const char *branch2)
 {
 	char *new_path = NULL;
-	if (dir_in_way(o->repo->index, path, !o->call_depth, 0)) {
-		new_path = unique_path(o, path, branch1);
-		output(o, 1, _("%s is a directory in %s adding "
+	if (dir_in_way(opt->repo->index, path, !opt->call_depth, 0)) {
+		new_path = unique_path(opt, path, branch1);
+		output(opt, 1, _("%s is a directory in %s adding "
 			       "as %s instead"),
 		       path, branch2, new_path);
-	} else if (would_lose_untracked(o, path)) {
-		new_path = unique_path(o, path, branch1);
-		output(o, 1, _("Refusing to lose untracked file"
+	} else if (would_lose_untracked(opt, path)) {
+		new_path = unique_path(opt, path, branch1);
+		output(opt, 1, _("Refusing to lose untracked file"
 			       " at %s; adding as %s instead"),
 		       path, new_path);
 	}
@@ -1743,7 +1743,7 @@ static char *find_path_for_conflict(struct merge_options *o,
 	return new_path;
 }
 
-static int handle_rename_rename_1to2(struct merge_options *o,
+static int handle_rename_rename_1to2(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
 	/* One file was renamed in both branches, but to different names. */
@@ -1755,29 +1755,29 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 	struct diff_filespec *b = ci->pair2->two;
 	char *path_desc;
 
-	output(o, 1, _("CONFLICT (rename/rename): "
+	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
 	       one->path, a->path, ci->branch1,
 	       one->path, b->path, ci->branch2,
-	       o->call_depth ? _(" (left unresolved)") : "");
+	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
 			    a->path, b->path, one->path);
-	if (merge_mode_and_contents(o, one, a, b, path_desc,
+	if (merge_mode_and_contents(opt, one, a, b, path_desc,
 				    ci->branch1, ci->branch2,
-				    o->call_depth * 2, &mfi))
+				    opt->call_depth * 2, &mfi))
 		return -1;
 	free(path_desc);
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		/*
 		 * FIXME: For rename/add-source conflicts (if we could detect
 		 * such), this is wrong.  We should instead find a unique
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
+		if (update_file(opt, 0, &mfi.oid, mfi.mode, one->path))
 			return -1;
 
 		/*
@@ -1790,18 +1790,18 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 		 */
 		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
 		if (add) {
-			if (update_file(o, 0, &add->oid, add->mode, a->path))
+			if (update_file(opt, 0, &add->oid, add->mode, a->path))
 				return -1;
 		}
 		else
-			remove_file_from_index(o->repo->index, a->path);
+			remove_file_from_index(opt->repo->index, a->path);
 		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
 		if (add) {
-			if (update_file(o, 0, &add->oid, add->mode, b->path))
+			if (update_file(opt, 0, &add->oid, add->mode, b->path))
 				return -1;
 		}
 		else
-			remove_file_from_index(o->repo->index, b->path);
+			remove_file_from_index(opt->repo->index, b->path);
 	} else {
 		/*
 		 * For each destination path, we need to see if there is a
@@ -1810,39 +1810,39 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 		 */
 		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
 		if (add) {
-			if (handle_file_collision(o, a->path,
+			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
 						  ci->branch1, ci->branch2,
 						  &mfi.oid, mfi.mode,
 						  &add->oid, add->mode) < 0)
 				return -1;
 		} else {
-			char *new_path = find_path_for_conflict(o, a->path,
+			char *new_path = find_path_for_conflict(opt, a->path,
 								ci->branch1,
 								ci->branch2);
-			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
+			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
-			if (update_stages(o, a->path, NULL, a, NULL))
+			if (update_stages(opt, a->path, NULL, a, NULL))
 				return -1;
 		}
 
 		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
 		if (add) {
-			if (handle_file_collision(o, b->path,
+			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
 						  ci->branch1, ci->branch2,
 						  &add->oid, add->mode,
 						  &mfi.oid, mfi.mode) < 0)
 				return -1;
 		} else {
-			char *new_path = find_path_for_conflict(o, b->path,
+			char *new_path = find_path_for_conflict(opt, b->path,
 								ci->branch2,
 								ci->branch1);
-			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
+			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
 				return -1;
 			free(new_path);
-			if (update_stages(o, b->path, NULL, NULL, b))
+			if (update_stages(opt, b->path, NULL, NULL, b))
 				return -1;
 		}
 	}
@@ -1850,7 +1850,7 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 	return 0;
 }
 
-static int handle_rename_rename_2to1(struct merge_options *o,
+static int handle_rename_rename_2to1(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
 	/* Two files, a & b, were renamed to the same thing, c. */
@@ -1864,7 +1864,7 @@ static int handle_rename_rename_2to1(struct merge_options *o,
 	struct merge_file_info mfi_c1;
 	struct merge_file_info mfi_c2;
 
-	output(o, 1, _("CONFLICT (rename/rename): "
+	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
 	       "Rename %s->%s in %s"),
 	       a->path, c1->path, ci->branch1,
@@ -1872,17 +1872,17 @@ static int handle_rename_rename_2to1(struct merge_options *o,
 
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	if (merge_mode_and_contents(o, a, c1, &ci->ren1_other, path_side_1_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(o, b, &ci->ren2_other, c2, path_side_2_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi_c2))
+	if (merge_mode_and_contents(opt, a, c1, &ci->ren1_other, path_side_1_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi_c1) ||
+	    merge_mode_and_contents(opt, b, &ci->ren2_other, c2, path_side_2_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi_c2))
 		return -1;
 	free(path_side_1_desc);
 	free(path_side_2_desc);
 
-	return handle_file_collision(o, path, a->path, b->path,
+	return handle_file_collision(opt, path, a->path, b->path,
 				     ci->branch1, ci->branch2,
 				     &mfi_c1.oid, mfi_c1.mode,
 				     &mfi_c2.oid, mfi_c2.mode);
@@ -1891,17 +1891,17 @@ static int handle_rename_rename_2to1(struct merge_options *o,
 /*
  * Get the diff_filepairs changed between o_tree and tree.
  */
-static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
+static struct diff_queue_struct *get_diffpairs(struct merge_options *opt,
 					       struct tree *o_tree,
 					       struct tree *tree)
 {
 	struct diff_queue_struct *ret;
 	struct diff_options opts;
 
-	repo_diff_setup(o->repo, &opts);
+	repo_diff_setup(opt->repo, &opts);
 	opts.flags.recursive = 1;
 	opts.flags.rename_empty = 0;
-	opts.detect_rename = merge_detect_rename(o);
+	opts.detect_rename = merge_detect_rename(opt);
 	/*
 	 * We do not have logic to handle the detection of copies.  In
 	 * fact, it may not even make sense to add such logic: would we
@@ -1910,17 +1910,17 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 	 */
 	if (opts.detect_rename > DIFF_DETECT_RENAME)
 		opts.detect_rename = DIFF_DETECT_RENAME;
-	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
-			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
+	opts.rename_limit = opt->merge_rename_limit >= 0 ? opt->merge_rename_limit :
+			    opt->diff_rename_limit >= 0 ? opt->diff_rename_limit :
 			    1000;
-	opts.rename_score = o->rename_score;
-	opts.show_rename_progress = o->show_rename_progress;
+	opts.rename_score = opt->rename_score;
+	opts.show_rename_progress = opt->show_rename_progress;
 	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 	diff_setup_done(&opts);
 	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
 	diffcore_std(&opts);
-	if (opts.needed_rename_limit > o->needed_rename_limit)
-		o->needed_rename_limit = opts.needed_rename_limit;
+	if (opts.needed_rename_limit > opt->needed_rename_limit)
+		opt->needed_rename_limit = opts.needed_rename_limit;
 
 	ret = xmalloc(sizeof(*ret));
 	*ret = diff_queued_diff;
@@ -2039,7 +2039,7 @@ static void remove_hashmap_entries(struct hashmap *dir_renames,
  * level conflicts for the renamed location.  If there is a rename and
  * there are no conflicts, return the new name.  Otherwise, return NULL.
  */
-static char *handle_path_level_conflicts(struct merge_options *o,
+static char *handle_path_level_conflicts(struct merge_options *opt,
 					 const char *path,
 					 struct dir_rename_entry *entry,
 					 struct hashmap *collisions,
@@ -2060,7 +2060,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		/* This should only happen when entry->non_unique_new_dir set */
 		if (!entry->non_unique_new_dir)
 			BUG("entry->non_unqiue_dir not set and !new_path");
-		output(o, 1, _("CONFLICT (directory rename split): "
+		output(opt, 1, _("CONFLICT (directory rename split): "
 			       "Unclear where to place %s because directory "
 			       "%s was renamed to multiple other directories, "
 			       "with no destination getting a majority of the "
@@ -2092,7 +2092,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		collision_ent->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &collision_ent->source_files);
-		output(o, 1, _("CONFLICT (implicit dir rename): Existing "
+		output(opt, 1, _("CONFLICT (implicit dir rename): Existing "
 			       "file/dir at %s in the way of implicit "
 			       "directory rename(s) putting the following "
 			       "path(s) there: %s."),
@@ -2102,7 +2102,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		collision_ent->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &collision_ent->source_files);
-		output(o, 1, _("CONFLICT (implicit dir rename): Cannot map "
+		output(opt, 1, _("CONFLICT (implicit dir rename): Cannot map "
 			       "more than one path to %s; implicit directory "
 			       "renames tried to put these paths there: %s"),
 		       new_path, collision_paths.buf);
@@ -2139,7 +2139,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
  *         causes conflicts for files within those merged directories, then
  *         that should be detected at the individual path level.
  */
-static void handle_directory_level_conflicts(struct merge_options *o,
+static void handle_directory_level_conflicts(struct merge_options *opt,
 					     struct hashmap *dir_re_head,
 					     struct tree *head,
 					     struct hashmap *dir_re_merge,
@@ -2194,11 +2194,11 @@ static void handle_directory_level_conflicts(struct merge_options *o,
 			 * know that head_ent->new_dir and merge_ent->new_dir
 			 * are different strings.
 			 */
-			output(o, 1, _("CONFLICT (rename/rename): "
+			output(opt, 1, _("CONFLICT (rename/rename): "
 				       "Rename directory %s->%s in %s. "
 				       "Rename directory %s->%s in %s"),
-			       head_ent->dir, head_ent->new_dir.buf, o->branch1,
-			       head_ent->dir, merge_ent->new_dir.buf, o->branch2);
+			       head_ent->dir, head_ent->new_dir.buf, opt->branch1,
+			       head_ent->dir, merge_ent->new_dir.buf, opt->branch2);
 			string_list_append(&remove_from_head,
 					   head_ent->dir)->util = head_ent;
 			strbuf_release(&head_ent->new_dir);
@@ -2397,7 +2397,7 @@ static void compute_collisions(struct hashmap *collisions,
 	}
 }
 
-static char *check_for_directory_rename(struct merge_options *o,
+static char *check_for_directory_rename(struct merge_options *opt,
 					const char *path,
 					struct tree *tree,
 					struct hashmap *dir_renames,
@@ -2438,11 +2438,11 @@ static char *check_for_directory_rename(struct merge_options *o,
 	 */
 	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
 	if (oentry) {
-		output(o, 1, _("WARNING: Avoiding applying %s -> %s rename "
+		output(opt, 1, _("WARNING: Avoiding applying %s -> %s rename "
 			       "to %s, because %s itself was renamed."),
 		       entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
 	} else {
-		new_path = handle_path_level_conflicts(o, path, entry,
+		new_path = handle_path_level_conflicts(opt, path, entry,
 						       collisions, tree);
 		*clean_merge &= (new_path != NULL);
 	}
@@ -2450,7 +2450,7 @@ static char *check_for_directory_rename(struct merge_options *o,
 	return new_path;
 }
 
-static void apply_directory_rename_modifications(struct merge_options *o,
+static void apply_directory_rename_modifications(struct merge_options *opt,
 						 struct diff_filepair *pair,
 						 char *new_path,
 						 struct rename *re,
@@ -2473,11 +2473,11 @@ static void apply_directory_rename_modifications(struct merge_options *o,
 	 * saying the file would have been overwritten), but it might
 	 * be dirty, though.
 	 */
-	update_wd = !was_dirty(o, pair->two->path);
+	update_wd = !was_dirty(opt, pair->two->path);
 	if (!update_wd)
-		output(o, 1, _("Refusing to lose dirty file at %s"),
+		output(opt, 1, _("Refusing to lose dirty file at %s"),
 		       pair->two->path);
-	remove_file(o, 1, pair->two->path, !update_wd);
+	remove_file(opt, 1, pair->two->path, !update_wd);
 
 	/* Find or create a new re->dst_entry */
 	item = string_list_lookup(entries, new_path);
@@ -2566,7 +2566,7 @@ static void apply_directory_rename_modifications(struct merge_options *o,
  * to be able to associate the correct cache entries with the rename
  * information; tree is always equal to either a_tree or b_tree.
  */
-static struct string_list *get_renames(struct merge_options *o,
+static struct string_list *get_renames(struct merge_options *opt,
 				       struct diff_queue_struct *pairs,
 				       struct hashmap *dir_renames,
 				       struct hashmap *dir_rename_exclusions,
@@ -2596,7 +2596,7 @@ static struct string_list *get_renames(struct merge_options *o,
 			diff_free_filepair(pair);
 			continue;
 		}
-		new_path = check_for_directory_rename(o, pair->two->path, tree,
+		new_path = check_for_directory_rename(opt, pair->two->path, tree,
 						      dir_renames,
 						      dir_rename_exclusions,
 						      &collisions,
@@ -2626,7 +2626,7 @@ static struct string_list *get_renames(struct merge_options *o,
 		item = string_list_insert(renames, pair->one->path);
 		item->util = re;
 		if (new_path)
-			apply_directory_rename_modifications(o, pair, new_path,
+			apply_directory_rename_modifications(opt, pair, new_path,
 							     re, tree, o_tree,
 							     a_tree, b_tree,
 							     entries);
@@ -2641,7 +2641,7 @@ static struct string_list *get_renames(struct merge_options *o,
 	return renames;
 }
 
-static int process_renames(struct merge_options *o,
+static int process_renames(struct merge_options *opt,
 			   struct string_list *a_renames,
 			   struct string_list *b_renames)
 {
@@ -2685,13 +2685,13 @@ static int process_renames(struct merge_options *o,
 		if (ren1) {
 			renames1 = a_renames;
 			renames2Dst = &b_by_dst;
-			branch1 = o->branch1;
-			branch2 = o->branch2;
+			branch1 = opt->branch1;
+			branch2 = opt->branch2;
 		} else {
 			renames1 = b_renames;
 			renames2Dst = &a_by_dst;
-			branch1 = o->branch2;
-			branch2 = o->branch1;
+			branch1 = opt->branch2;
+			branch2 = opt->branch1;
 			SWAP(ren2, ren1);
 		}
 
@@ -2725,7 +2725,7 @@ static int process_renames(struct merge_options *o,
 				 * the base stage (think of rename +
 				 * add-source cases).
 				 */
-				remove_file(o, 1, ren1_src, 1);
+				remove_file(opt, 1, ren1_src, 1);
 				update_entry(ren1->dst_entry,
 					     ren1->pair->one,
 					     ren1->pair->two,
@@ -2738,7 +2738,7 @@ static int process_renames(struct merge_options *o,
 						   branch2,
 						   ren1->dst_entry,
 						   ren2->dst_entry,
-						   o,
+						   opt,
 						   NULL,
 						   NULL);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
@@ -2765,7 +2765,7 @@ static int process_renames(struct merge_options *o,
 						   branch2,
 						   ren1->dst_entry,
 						   ren2->dst_entry,
-						   o,
+						   opt,
 						   ren1->src_entry,
 						   ren2->src_entry);
 
@@ -2788,8 +2788,8 @@ static int process_renames(struct merge_options *o,
 			 * stage and in other_stage (think of rename +
 			 * add-source case).
 			 */
-			remove_file(o, 1, ren1_src,
-				    renamed_stage == 2 || !was_tracked(o, ren1_src));
+			remove_file(opt, 1, ren1_src,
+				    renamed_stage == 2 || !was_tracked(opt, ren1_src));
 
 			oidcpy(&src_other.oid,
 			       &ren1->src_entry->stages[other_stage].oid);
@@ -2808,7 +2808,7 @@ static int process_renames(struct merge_options *o,
 							   branch2,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   NULL,
 							   NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
@@ -2819,7 +2819,7 @@ static int process_renames(struct merge_options *o,
 							   branch2,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   NULL,
 							   NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
@@ -2832,7 +2832,7 @@ static int process_renames(struct merge_options *o,
 				 * update_file_flags() instead of
 				 * update_file().
 				 */
-				if (update_file_flags(o,
+				if (update_file_flags(opt,
 						      &ren1->pair->two->oid,
 						      ren1->pair->two->mode,
 						      ren1_dst,
@@ -2854,7 +2854,7 @@ static int process_renames(struct merge_options *o,
 							   branch2,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   ren1->src_entry,
 							   NULL);
 			} else
@@ -2882,7 +2882,7 @@ static int process_renames(struct merge_options *o,
 							   NULL,
 							   ren1->dst_entry,
 							   NULL,
-							   o,
+							   opt,
 							   NULL,
 							   NULL);
 			}
@@ -2919,7 +2919,7 @@ static void initial_cleanup_rename(struct diff_queue_struct *pairs,
 	free(pairs);
 }
 
-static int detect_and_process_renames(struct merge_options *o,
+static int detect_and_process_renames(struct merge_options *opt,
 				      struct tree *common,
 				      struct tree *head,
 				      struct tree *merge,
@@ -2933,17 +2933,17 @@ static int detect_and_process_renames(struct merge_options *o,
 	ri->head_renames = NULL;
 	ri->merge_renames = NULL;
 
-	if (!merge_detect_rename(o))
+	if (!merge_detect_rename(opt))
 		return 1;
 
-	head_pairs = get_diffpairs(o, common, head);
-	merge_pairs = get_diffpairs(o, common, merge);
+	head_pairs = get_diffpairs(opt, common, head);
+	merge_pairs = get_diffpairs(opt, common, merge);
 
-	if (o->detect_directory_renames) {
+	if (opt->detect_directory_renames) {
 		dir_re_head = get_directory_renames(head_pairs);
 		dir_re_merge = get_directory_renames(merge_pairs);
 
-		handle_directory_level_conflicts(o,
+		handle_directory_level_conflicts(opt,
 						 dir_re_head, head,
 						 dir_re_merge, merge);
 	} else {
@@ -2953,19 +2953,19 @@ static int detect_and_process_renames(struct merge_options *o,
 		dir_rename_init(dir_re_merge);
 	}
 
-	ri->head_renames  = get_renames(o, head_pairs,
+	ri->head_renames  = get_renames(opt, head_pairs,
 					dir_re_merge, dir_re_head, head,
 					common, head, merge, entries,
 					&clean);
 	if (clean < 0)
 		goto cleanup;
-	ri->merge_renames = get_renames(o, merge_pairs,
+	ri->merge_renames = get_renames(opt, merge_pairs,
 					dir_re_head, dir_re_merge, merge,
 					common, head, merge, entries,
 					&clean);
 	if (clean < 0)
 		goto cleanup;
-	clean &= process_renames(o, ri->head_renames, ri->merge_renames);
+	clean &= process_renames(opt, ri->head_renames, ri->merge_renames);
 
 cleanup:
 	/*
@@ -3006,7 +3006,7 @@ static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
 	return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
 }
 
-static int read_oid_strbuf(struct merge_options *o,
+static int read_oid_strbuf(struct merge_options *opt,
 			   const struct object_id *oid,
 			   struct strbuf *dst)
 {
@@ -3015,10 +3015,10 @@ static int read_oid_strbuf(struct merge_options *o,
 	unsigned long size;
 	buf = read_object_file(oid, &type, &size);
 	if (!buf)
-		return err(o, _("cannot read object %s"), oid_to_hex(oid));
+		return err(opt, _("cannot read object %s"), oid_to_hex(oid));
 	if (type != OBJ_BLOB) {
 		free(buf);
-		return err(o, _("object %s is not a blob"), oid_to_hex(oid));
+		return err(opt, _("object %s is not a blob"), oid_to_hex(oid));
 	}
 	strbuf_attach(dst, buf, size, size + 1);
 	return 0;
@@ -3060,7 +3060,7 @@ static int blob_unchanged(struct merge_options *opt,
 	return ret;
 }
 
-static int handle_modify_delete(struct merge_options *o,
+static int handle_modify_delete(struct merge_options *opt,
 				const char *path,
 				struct object_id *o_oid, int o_mode,
 				struct object_id *a_oid, int a_mode,
@@ -3071,18 +3071,18 @@ static int handle_modify_delete(struct merge_options *o,
 	int changed_mode;
 
 	if (a_oid) {
-		modify_branch = o->branch1;
-		delete_branch = o->branch2;
+		modify_branch = opt->branch1;
+		delete_branch = opt->branch2;
 		changed_oid = a_oid;
 		changed_mode = a_mode;
 	} else {
-		modify_branch = o->branch2;
-		delete_branch = o->branch1;
+		modify_branch = opt->branch2;
+		delete_branch = opt->branch1;
 		changed_oid = b_oid;
 		changed_mode = b_mode;
 	}
 
-	return handle_change_delete(o,
+	return handle_change_delete(opt,
 				    path, NULL,
 				    o_oid, o_mode,
 				    changed_oid, changed_mode,
@@ -3090,7 +3090,7 @@ static int handle_modify_delete(struct merge_options *o,
 				    _("modify"), _("modified"));
 }
 
-static int handle_content_merge(struct merge_options *o,
+static int handle_content_merge(struct merge_options *opt,
 				const char *path,
 				int is_dirty,
 				struct object_id *o_oid, int o_mode,
@@ -3119,26 +3119,26 @@ static int handle_content_merge(struct merge_options *o,
 	if (rename_conflict_info) {
 		struct diff_filepair *pair1 = rename_conflict_info->pair1;
 
-		path1 = (o->branch1 == rename_conflict_info->branch1) ?
+		path1 = (opt->branch1 == rename_conflict_info->branch1) ?
 			pair1->two->path : pair1->one->path;
 		/* If rename_conflict_info->pair2 != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
 		path2 = (rename_conflict_info->pair2 ||
-			 o->branch2 == rename_conflict_info->branch1) ?
+			 opt->branch2 == rename_conflict_info->branch1) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
 		a.path = (char *)path1;
 		b.path = (char *)path2;
 
-		if (dir_in_way(o->repo->index, path, !o->call_depth,
+		if (dir_in_way(opt->repo->index, path, !opt->call_depth,
 			       S_ISGITLINK(pair1->two->mode)))
 			df_conflict_remains = 1;
 	}
-	if (merge_mode_and_contents(o, &one, &a, &b, path,
-				    o->branch1, o->branch2,
-				    o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, &one, &a, &b, path,
+				    opt->branch1, opt->branch2,
+				    opt->call_depth * 2, &mfi))
 		return -1;
 
 	/*
@@ -3148,14 +3148,14 @@ static int handle_content_merge(struct merge_options *o,
 	 *   c) The target path is usable (i.e. not involved in D/F conflict)
 	 */
 	if (mfi.clean &&
-	    was_tracked_and_matches(o, path, &mfi.oid, mfi.mode) &&
+	    was_tracked_and_matches(opt, path, &mfi.oid, mfi.mode) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
-		output(o, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(o, mfi.mode, &mfi.oid, path,
-				  0, (!o->call_depth && !is_dirty), 0))
+		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
+		if (add_cacheinfo(opt, mfi.mode, &mfi.oid, path,
+				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
 		 * However, add_cacheinfo() will delete the old cache entry
@@ -3163,11 +3163,11 @@ static int handle_content_merge(struct merge_options *o,
 		 * flag to avoid making the file appear as if it were
 		 * deleted by the user.
 		 */
-		pos = index_name_pos(&o->orig_index, path, strlen(path));
-		ce = o->orig_index.cache[pos];
+		pos = index_name_pos(&opt->orig_index, path, strlen(path));
+		ce = opt->orig_index.cache[pos];
 		if (ce_skip_worktree(ce)) {
-			pos = index_name_pos(o->repo->index, path, strlen(path));
-			ce = o->repo->index->cache[pos];
+			pos = index_name_pos(opt->repo->index, path, strlen(path));
+			ce = opt->repo->index->cache[pos];
 			ce->ce_flags |= CE_SKIP_WORKTREE;
 		}
 		return mfi.clean;
@@ -3176,52 +3176,52 @@ static int handle_content_merge(struct merge_options *o,
 	if (!mfi.clean) {
 		if (S_ISGITLINK(mfi.mode))
 			reason = _("submodule");
-		output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
+		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
 		if (rename_conflict_info && !df_conflict_remains)
-			if (update_stages(o, path, &one, &a, &b))
+			if (update_stages(opt, path, &one, &a, &b))
 				return -1;
 	}
 
 	if (df_conflict_remains || is_dirty) {
 		char *new_path;
-		if (o->call_depth) {
-			remove_file_from_index(o->repo->index, path);
+		if (opt->call_depth) {
+			remove_file_from_index(opt->repo->index, path);
 		} else {
 			if (!mfi.clean) {
-				if (update_stages(o, path, &one, &a, &b))
+				if (update_stages(opt, path, &one, &a, &b))
 					return -1;
 			} else {
-				int file_from_stage2 = was_tracked(o, path);
+				int file_from_stage2 = was_tracked(opt, path);
 				struct diff_filespec merged;
 				oidcpy(&merged.oid, &mfi.oid);
 				merged.mode = mfi.mode;
 
-				if (update_stages(o, path, NULL,
+				if (update_stages(opt, path, NULL,
 						  file_from_stage2 ? &merged : NULL,
 						  file_from_stage2 ? NULL : &merged))
 					return -1;
 			}
 
 		}
-		new_path = unique_path(o, path, rename_conflict_info->branch1);
+		new_path = unique_path(opt, path, rename_conflict_info->branch1);
 		if (is_dirty) {
-			output(o, 1, _("Refusing to lose dirty file at %s"),
+			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
 		}
-		output(o, 1, _("Adding as %s instead"), new_path);
-		if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
+		output(opt, 1, _("Adding as %s instead"), new_path);
+		if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path)) {
 			free(new_path);
 			return -1;
 		}
 		free(new_path);
 		mfi.clean = 0;
-	} else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
+	} else if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, path))
 		return -1;
 	return !is_dirty && mfi.clean;
 }
 
-static int handle_rename_normal(struct merge_options *o,
+static int handle_rename_normal(struct merge_options *opt,
 				const char *path,
 				struct object_id *o_oid, unsigned int o_mode,
 				struct object_id *a_oid, unsigned int a_mode,
@@ -3229,17 +3229,17 @@ static int handle_rename_normal(struct merge_options *o,
 				struct rename_conflict_info *ci)
 {
 	/* Merge the content and write it out */
-	return handle_content_merge(o, path, was_dirty(o, path),
+	return handle_content_merge(opt, path, was_dirty(opt, path),
 				    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
 				    ci);
 }
 
 /* Per entry merge function */
-static int process_entry(struct merge_options *o,
+static int process_entry(struct merge_options *opt,
 			 const char *path, struct stage_data *entry)
 {
 	int clean_merge = 1;
-	int normalize = o->renormalize;
+	int normalize = opt->renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -3253,7 +3253,7 @@ static int process_entry(struct merge_options *o,
 		switch (conflict_info->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
-			clean_merge = handle_rename_normal(o,
+			clean_merge = handle_rename_normal(opt,
 							   path,
 							   o_oid, o_mode,
 							   a_oid, a_mode,
@@ -3262,7 +3262,7 @@ static int process_entry(struct merge_options *o,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(o,
+			if (handle_rename_via_dir(opt,
 						  conflict_info->pair1,
 						  conflict_info->branch1))
 				clean_merge = -1;
@@ -3274,11 +3274,11 @@ static int process_entry(struct merge_options *o,
 			 * two-way merged cleanly with the added file, I
 			 * guess it's a clean merge?
 			 */
-			clean_merge = handle_rename_add(o, conflict_info);
+			clean_merge = handle_rename_add(opt, conflict_info);
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(o,
+			if (handle_rename_delete(opt,
 						 conflict_info->pair1,
 						 conflict_info->branch1,
 						 conflict_info->branch2))
@@ -3286,7 +3286,7 @@ static int process_entry(struct merge_options *o,
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
 			clean_merge = 0;
-			if (handle_rename_rename_1to2(o, conflict_info))
+			if (handle_rename_rename_1to2(opt, conflict_info))
 				clean_merge = -1;
 			break;
 		case RENAME_TWO_FILES_TO_ONE:
@@ -3296,7 +3296,7 @@ static int process_entry(struct merge_options *o,
 			 * can then be two-way merged cleanly, I guess it's
 			 * a clean merge?
 			 */
-			clean_merge = handle_rename_rename_2to1(o,
+			clean_merge = handle_rename_rename_2to1(opt,
 								conflict_info);
 			break;
 		default:
@@ -3306,18 +3306,18 @@ static int process_entry(struct merge_options *o,
 	} else if (o_oid && (!a_oid || !b_oid)) {
 		/* Case A: Deleted in one */
 		if ((!a_oid && !b_oid) ||
-		    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
-		    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
+		    (!b_oid && blob_unchanged(opt, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
+		    (!a_oid && blob_unchanged(opt, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_oid)
-				output(o, 2, _("Removing %s"), path);
+				output(opt, 2, _("Removing %s"), path);
 			/* do not touch working file if it did not exist */
-			remove_file(o, 1, path, !a_oid);
+			remove_file(opt, 1, path, !a_oid);
 		} else {
 			/* Modify/delete; deleted side may have put a directory in the way */
 			clean_merge = 0;
-			if (handle_modify_delete(o, path, o_oid, o_mode,
+			if (handle_modify_delete(opt, path, o_oid, o_mode,
 						 a_oid, a_mode, b_oid, b_mode))
 				clean_merge = -1;
 		}
@@ -3333,53 +3333,53 @@ static int process_entry(struct merge_options *o,
 		const char *conf;
 
 		if (a_oid) {
-			add_branch = o->branch1;
-			other_branch = o->branch2;
+			add_branch = opt->branch1;
+			other_branch = opt->branch2;
 			mode = a_mode;
 			oid = a_oid;
 			conf = _("file/directory");
 		} else {
-			add_branch = o->branch2;
-			other_branch = o->branch1;
+			add_branch = opt->branch2;
+			other_branch = opt->branch1;
 			mode = b_mode;
 			oid = b_oid;
 			conf = _("directory/file");
 		}
-		if (dir_in_way(o->repo->index, path,
-			       !o->call_depth && !S_ISGITLINK(a_mode),
+		if (dir_in_way(opt->repo->index, path,
+			       !opt->call_depth && !S_ISGITLINK(a_mode),
 			       0)) {
-			char *new_path = unique_path(o, path, add_branch);
+			char *new_path = unique_path(opt, path, add_branch);
 			clean_merge = 0;
-			output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
+			output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
 			       "Adding %s as %s"),
 			       conf, path, other_branch, path, new_path);
-			if (update_file(o, 0, oid, mode, new_path))
+			if (update_file(opt, 0, oid, mode, new_path))
 				clean_merge = -1;
-			else if (o->call_depth)
-				remove_file_from_index(o->repo->index, path);
+			else if (opt->call_depth)
+				remove_file_from_index(opt->repo->index, path);
 			free(new_path);
 		} else {
-			output(o, 2, _("Adding %s"), path);
+			output(opt, 2, _("Adding %s"), path);
 			/* do not overwrite file if already present */
-			if (update_file_flags(o, oid, mode, path, 1, !a_oid))
+			if (update_file_flags(opt, oid, mode, path, 1, !a_oid))
 				clean_merge = -1;
 		}
 	} else if (a_oid && b_oid) {
 		if (!o_oid) {
 			/* Case C: Added in both (check for same permissions) */
-			output(o, 1,
+			output(opt, 1,
 			       _("CONFLICT (add/add): Merge conflict in %s"),
 			       path);
-			clean_merge = handle_file_collision(o,
+			clean_merge = handle_file_collision(opt,
 							    path, NULL, NULL,
-							    o->branch1,
-							    o->branch2,
+							    opt->branch1,
+							    opt->branch2,
 							    a_oid, a_mode,
 							    b_oid, b_mode);
 		} else {
 			/* case D: Modified in both, but differently. */
 			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(o, path,
+			clean_merge = handle_content_merge(opt, path,
 							   is_dirty,
 							   o_oid, o_mode,
 							   a_oid, a_mode,
@@ -3391,48 +3391,48 @@ static int process_entry(struct merge_options *o,
 		 * this entry was deleted altogether. a_mode == 0 means
 		 * we had that path and want to actively remove it.
 		 */
-		remove_file(o, 1, path, !a_mode);
+		remove_file(opt, 1, path, !a_mode);
 	} else
 		BUG("fatal merge failure, shouldn't happen.");
 
 	return clean_merge;
 }
 
-int merge_trees(struct merge_options *o,
+int merge_trees(struct merge_options *opt,
 		struct tree *head,
 		struct tree *merge,
 		struct tree *common,
 		struct tree **result)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 	int code, clean;
 	struct strbuf sb = STRBUF_INIT;
 
-	if (!o->call_depth && repo_index_has_changes(o->repo, head, &sb)) {
-		err(o, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
+	if (!opt->call_depth && repo_index_has_changes(opt->repo, head, &sb)) {
+		err(opt, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
 		    sb.buf);
 		return -1;
 	}
 
-	if (o->subtree_shift) {
-		merge = shift_tree_object(o->repo, head, merge, o->subtree_shift);
-		common = shift_tree_object(o->repo, head, common, o->subtree_shift);
+	if (opt->subtree_shift) {
+		merge = shift_tree_object(opt->repo, head, merge, opt->subtree_shift);
+		common = shift_tree_object(opt->repo, head, common, opt->subtree_shift);
 	}
 
 	if (oid_eq(&common->object.oid, &merge->object.oid)) {
-		output(o, 0, _("Already up to date!"));
+		output(opt, 0, _("Already up to date!"));
 		*result = head;
 		return 1;
 	}
 
-	code = unpack_trees_start(o, common, head, merge);
+	code = unpack_trees_start(opt, common, head, merge);
 
 	if (code != 0) {
-		if (show(o, 4) || o->call_depth)
-			err(o, _("merging of trees %s and %s failed"),
+		if (show(opt, 4) || opt->call_depth)
+			err(opt, _("merging of trees %s and %s failed"),
 			    oid_to_hex(&head->object.oid),
 			    oid_to_hex(&merge->object.oid));
-		unpack_trees_finish(o);
+		unpack_trees_finish(opt);
 		return -1;
 	}
 
@@ -3447,21 +3447,21 @@ int merge_trees(struct merge_options *o,
 		 * opposed to decaring a local hashmap is for convenience
 		 * so that we don't have to pass it to around.
 		 */
-		hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
-		get_files_dirs(o, head);
-		get_files_dirs(o, merge);
+		hashmap_init(&opt->current_file_dir_set, path_hashmap_cmp, NULL, 512);
+		get_files_dirs(opt, head);
+		get_files_dirs(opt, merge);
 
-		entries = get_unmerged(o->repo->index);
-		clean = detect_and_process_renames(o, common, head, merge,
+		entries = get_unmerged(opt->repo->index);
+		clean = detect_and_process_renames(opt, common, head, merge,
 						   entries, &re_info);
-		record_df_conflict_files(o, entries);
+		record_df_conflict_files(opt, entries);
 		if (clean < 0)
 			goto cleanup;
 		for (i = entries->nr-1; 0 <= i; i--) {
 			const char *path = entries->items[i].string;
 			struct stage_data *e = entries->items[i].util;
 			if (!e->processed) {
-				int ret = process_entry(o, path, e);
+				int ret = process_entry(opt, path, e);
 				if (!ret)
 					clean = 0;
 				else if (ret < 0) {
@@ -3483,19 +3483,19 @@ int merge_trees(struct merge_options *o,
 		string_list_clear(entries, 1);
 		free(entries);
 
-		hashmap_free(&o->current_file_dir_set, 1);
+		hashmap_free(&opt->current_file_dir_set, 1);
 
 		if (clean < 0) {
-			unpack_trees_finish(o);
+			unpack_trees_finish(opt);
 			return clean;
 		}
 	}
 	else
 		clean = 1;
 
-	unpack_trees_finish(o);
+	unpack_trees_finish(opt);
 
-	if (o->call_depth && !(*result = write_tree_from_memory(o)))
+	if (opt->call_depth && !(*result = write_tree_from_memory(opt)))
 		return -1;
 
 	return clean;
@@ -3516,7 +3516,7 @@ static struct commit_list *reverse_commit_list(struct commit_list *list)
  * Merge the commits h1 and h2, return the resulting virtual
  * commit object and a flag indicating the cleanness of the merge.
  */
-int merge_recursive(struct merge_options *o,
+int merge_recursive(struct merge_options *opt,
 		    struct commit *h1,
 		    struct commit *h2,
 		    struct commit_list *ca,
@@ -3527,10 +3527,10 @@ int merge_recursive(struct merge_options *o,
 	struct tree *mrtree;
 	int clean;
 
-	if (show(o, 4)) {
-		output(o, 4, _("Merging:"));
-		output_commit_title(o, h1);
-		output_commit_title(o, h2);
+	if (show(opt, 4)) {
+		output(opt, 4, _("Merging:"));
+		output_commit_title(opt, h1);
+		output_commit_title(opt, h2);
 	}
 
 	if (!ca) {
@@ -3538,13 +3538,13 @@ int merge_recursive(struct merge_options *o,
 		ca = reverse_commit_list(ca);
 	}
 
-	if (show(o, 5)) {
+	if (show(opt, 5)) {
 		unsigned cnt = commit_list_count(ca);
 
-		output(o, 5, Q_("found %u common ancestor:",
+		output(opt, 5, Q_("found %u common ancestor:",
 				"found %u common ancestors:", cnt), cnt);
 		for (iter = ca; iter; iter = iter->next)
-			output_commit_title(o, iter->item);
+			output_commit_title(opt, iter->item);
 	}
 
 	merged_common_ancestors = pop_commit(&ca);
@@ -3552,13 +3552,13 @@ int merge_recursive(struct merge_options *o,
 		/* if there is no common ancestor, use an empty tree */
 		struct tree *tree;
 
-		tree = lookup_tree(o->repo, o->repo->hash_algo->empty_tree);
-		merged_common_ancestors = make_virtual_commit(o->repo, tree, "ancestor");
+		tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree);
+		merged_common_ancestors = make_virtual_commit(opt->repo, tree, "ancestor");
 	}
 
 	for (iter = ca; iter; iter = iter->next) {
 		const char *saved_b1, *saved_b2;
-		o->call_depth++;
+		opt->call_depth++;
 		/*
 		 * When the merge fails, the result contains files
 		 * with conflict markers. The cleanness flag is
@@ -3567,46 +3567,46 @@ int merge_recursive(struct merge_options *o,
 		 * overwritten it: the committed "conflicts" were
 		 * already resolved.
 		 */
-		discard_index(o->repo->index);
-		saved_b1 = o->branch1;
-		saved_b2 = o->branch2;
-		o->branch1 = "Temporary merge branch 1";
-		o->branch2 = "Temporary merge branch 2";
-		if (merge_recursive(o, merged_common_ancestors, iter->item,
+		discard_index(opt->repo->index);
+		saved_b1 = opt->branch1;
+		saved_b2 = opt->branch2;
+		opt->branch1 = "Temporary merge branch 1";
+		opt->branch2 = "Temporary merge branch 2";
+		if (merge_recursive(opt, merged_common_ancestors, iter->item,
 				    NULL, &merged_common_ancestors) < 0)
 			return -1;
-		o->branch1 = saved_b1;
-		o->branch2 = saved_b2;
-		o->call_depth--;
+		opt->branch1 = saved_b1;
+		opt->branch2 = saved_b2;
+		opt->call_depth--;
 
 		if (!merged_common_ancestors)
-			return err(o, _("merge returned no commit"));
+			return err(opt, _("merge returned no commit"));
 	}
 
-	discard_index(o->repo->index);
-	if (!o->call_depth)
-		repo_read_index(o->repo);
+	discard_index(opt->repo->index);
+	if (!opt->call_depth)
+		repo_read_index(opt->repo);
 
-	o->ancestor = "merged common ancestors";
-	clean = merge_trees(o, get_commit_tree(h1), get_commit_tree(h2),
+	opt->ancestor = "merged common ancestors";
+	clean = merge_trees(opt, get_commit_tree(h1), get_commit_tree(h2),
 			    get_commit_tree(merged_common_ancestors),
 			    &mrtree);
 	if (clean < 0) {
-		flush_output(o);
+		flush_output(opt);
 		return clean;
 	}
 
-	if (o->call_depth) {
-		*result = make_virtual_commit(o->repo, mrtree, "merged tree");
+	if (opt->call_depth) {
+		*result = make_virtual_commit(opt->repo, mrtree, "merged tree");
 		commit_list_insert(h1, &(*result)->parents);
 		commit_list_insert(h2, &(*result)->parents->next);
 	}
-	flush_output(o);
-	if (!o->call_depth && o->buffer_output < 2)
-		strbuf_release(&o->obuf);
-	if (show(o, 2))
+	flush_output(opt);
+	if (!opt->call_depth && opt->buffer_output < 2)
+		strbuf_release(&opt->obuf);
+	if (show(opt, 2))
 		diff_warn_rename_limit("merge.renamelimit",
-				       o->needed_rename_limit, 0);
+				       opt->needed_rename_limit, 0);
 	return clean;
 }
 
@@ -3628,7 +3628,7 @@ static struct commit *get_ref(struct repository *repo, const struct object_id *o
 	return (struct commit *)object;
 }
 
-int merge_recursive_generic(struct merge_options *o,
+int merge_recursive_generic(struct merge_options *opt,
 			    const struct object_id *head,
 			    const struct object_id *merge,
 			    int num_base_list,
@@ -3637,127 +3637,127 @@ int merge_recursive_generic(struct merge_options *o,
 {
 	int clean;
 	struct lock_file lock = LOCK_INIT;
-	struct commit *head_commit = get_ref(o->repo, head, o->branch1);
-	struct commit *next_commit = get_ref(o->repo, merge, o->branch2);
+	struct commit *head_commit = get_ref(opt->repo, head, opt->branch1);
+	struct commit *next_commit = get_ref(opt->repo, merge, opt->branch2);
 	struct commit_list *ca = NULL;
 
 	if (base_list) {
 		int i;
 		for (i = 0; i < num_base_list; ++i) {
 			struct commit *base;
-			if (!(base = get_ref(o->repo, base_list[i], oid_to_hex(base_list[i]))))
-				return err(o, _("Could not parse object '%s'"),
+			if (!(base = get_ref(opt->repo, base_list[i], oid_to_hex(base_list[i]))))
+				return err(opt, _("Could not parse object '%s'"),
 					   oid_to_hex(base_list[i]));
 			commit_list_insert(base, &ca);
 		}
 	}
 
-	repo_hold_locked_index(o->repo, &lock, LOCK_DIE_ON_ERROR);
-	clean = merge_recursive(o, head_commit, next_commit, ca,
+	repo_hold_locked_index(opt->repo, &lock, LOCK_DIE_ON_ERROR);
+	clean = merge_recursive(opt, head_commit, next_commit, ca,
 				result);
 	if (clean < 0) {
 		rollback_lock_file(&lock);
 		return clean;
 	}
 
-	if (write_locked_index(o->repo->index, &lock,
+	if (write_locked_index(opt->repo->index, &lock,
 			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
-		return err(o, _("Unable to write index."));
+		return err(opt, _("Unable to write index."));
 
 	return clean ? 0 : 1;
 }
 
-static void merge_recursive_config(struct merge_options *o)
+static void merge_recursive_config(struct merge_options *opt)
 {
 	char *value = NULL;
-	git_config_get_int("merge.verbosity", &o->verbosity);
-	git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
-	git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
+	git_config_get_int("merge.verbosity", &opt->verbosity);
+	git_config_get_int("diff.renamelimit", &opt->diff_rename_limit);
+	git_config_get_int("merge.renamelimit", &opt->merge_rename_limit);
 	if (!git_config_get_string("diff.renames", &value)) {
-		o->diff_detect_rename = git_config_rename("diff.renames", value);
+		opt->diff_detect_rename = git_config_rename("diff.renames", value);
 		free(value);
 	}
 	if (!git_config_get_string("merge.renames", &value)) {
-		o->merge_detect_rename = git_config_rename("merge.renames", value);
+		opt->merge_detect_rename = git_config_rename("merge.renames", value);
 		free(value);
 	}
 	git_config(git_xmerge_config, NULL);
 }
 
-void init_merge_options(struct merge_options *o,
+void init_merge_options(struct merge_options *opt,
 			struct repository *repo)
 {
 	const char *merge_verbosity;
-	memset(o, 0, sizeof(struct merge_options));
-	o->repo = repo;
-	o->verbosity = 2;
-	o->buffer_output = 1;
-	o->diff_rename_limit = -1;
-	o->merge_rename_limit = -1;
-	o->renormalize = 0;
-	o->diff_detect_rename = -1;
-	o->merge_detect_rename = -1;
-	o->detect_directory_renames = 1;
-	merge_recursive_config(o);
+	memset(opt, 0, sizeof(struct merge_options));
+	opt->repo = repo;
+	opt->verbosity = 2;
+	opt->buffer_output = 1;
+	opt->diff_rename_limit = -1;
+	opt->merge_rename_limit = -1;
+	opt->renormalize = 0;
+	opt->diff_detect_rename = -1;
+	opt->merge_detect_rename = -1;
+	opt->detect_directory_renames = 1;
+	merge_recursive_config(opt);
 	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
 	if (merge_verbosity)
-		o->verbosity = strtol(merge_verbosity, NULL, 10);
-	if (o->verbosity >= 5)
-		o->buffer_output = 0;
-	strbuf_init(&o->obuf, 0);
-	string_list_init(&o->df_conflict_file_set, 1);
+		opt->verbosity = strtol(merge_verbosity, NULL, 10);
+	if (opt->verbosity >= 5)
+		opt->buffer_output = 0;
+	strbuf_init(&opt->obuf, 0);
+	string_list_init(&opt->df_conflict_file_set, 1);
 }
 
-int parse_merge_opt(struct merge_options *o, const char *s)
+int parse_merge_opt(struct merge_options *opt, const char *s)
 {
 	const char *arg;
 
 	if (!s || !*s)
 		return -1;
 	if (!strcmp(s, "ours"))
-		o->recursive_variant = MERGE_RECURSIVE_OURS;
+		opt->recursive_variant = MERGE_RECURSIVE_OURS;
 	else if (!strcmp(s, "theirs"))
-		o->recursive_variant = MERGE_RECURSIVE_THEIRS;
+		opt->recursive_variant = MERGE_RECURSIVE_THEIRS;
 	else if (!strcmp(s, "subtree"))
-		o->subtree_shift = "";
+		opt->subtree_shift = "";
 	else if (skip_prefix(s, "subtree=", &arg))
-		o->subtree_shift = arg;
+		opt->subtree_shift = arg;
 	else if (!strcmp(s, "patience"))
-		o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
+		opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
 	else if (!strcmp(s, "histogram"))
-		o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
+		opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
 	else if (skip_prefix(s, "diff-algorithm=", &arg)) {
 		long value = parse_algorithm_value(arg);
 		if (value < 0)
 			return -1;
 		/* clear out previous settings */
-		DIFF_XDL_CLR(o, NEED_MINIMAL);
-		o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
-		o->xdl_opts |= value;
+		DIFF_XDL_CLR(opt, NEED_MINIMAL);
+		opt->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
+		opt->xdl_opts |= value;
 	}
 	else if (!strcmp(s, "ignore-space-change"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE_CHANGE);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
 	else if (!strcmp(s, "ignore-all-space"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
 	else if (!strcmp(s, "ignore-space-at-eol"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
 	else if (!strcmp(s, "ignore-cr-at-eol"))
-		DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
+		DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
 	else if (!strcmp(s, "renormalize"))
-		o->renormalize = 1;
+		opt->renormalize = 1;
 	else if (!strcmp(s, "no-renormalize"))
-		o->renormalize = 0;
+		opt->renormalize = 0;
 	else if (!strcmp(s, "no-renames"))
-		o->merge_detect_rename = 0;
+		opt->merge_detect_rename = 0;
 	else if (!strcmp(s, "find-renames")) {
-		o->merge_detect_rename = 1;
-		o->rename_score = 0;
+		opt->merge_detect_rename = 1;
+		opt->rename_score = 0;
 	}
 	else if (skip_prefix(s, "find-renames=", &arg) ||
 		 skip_prefix(s, "rename-threshold=", &arg)) {
-		if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
+		if ((opt->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
 			return -1;
-		o->merge_detect_rename = 1;
+		opt->merge_detect_rename = 1;
 	}
 	/*
 	 * Please update $__git_merge_strategy_options in
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 03/15] merge-recursive: rename diff_filespec 'one' to 'o'

[Elijah Newren]

In the previous commit, we noted that several places throughout merge
recursive both had a reason to use 'o'; some for a merge_options struct,
and others for a diff_filespec struct.  Some places had both, forcing
one of the two to be renamed, though the choice was inconsistent.  Now
that the merge_options struct has been renamed to 'opt' everywhere, we
can replace the few places that used 'one' for the diff_filespec to 'o'.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 09b76d596e..36af5d9cc6 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1050,7 +1050,7 @@ struct merge_file_info {
 
 static int merge_3way(struct merge_options *opt,
 		      mmbuffer_t *result_buf,
-		      const struct diff_filespec *one,
+		      const struct diff_filespec *o,
 		      const struct diff_filespec *a,
 		      const struct diff_filespec *b,
 		      const char *branch1,
@@ -1084,9 +1084,9 @@ static int merge_3way(struct merge_options *opt,
 	}
 
 	if (strcmp(a->path, b->path) ||
-	    (opt->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
+	    (opt->ancestor != NULL && strcmp(a->path, o->path) != 0)) {
 		base_name = opt->ancestor == NULL ? NULL :
-			mkpathdup("%s:%s", opt->ancestor, one->path);
+			mkpathdup("%s:%s", opt->ancestor, o->path);
 		name1 = mkpathdup("%s:%s", branch1, a->path);
 		name2 = mkpathdup("%s:%s", branch2, b->path);
 	} else {
@@ -1096,7 +1096,7 @@ static int merge_3way(struct merge_options *opt,
 		name2 = mkpathdup("%s", branch2);
 	}
 
-	read_mmblob(&orig, &one->oid);
+	read_mmblob(&orig, &o->oid);
 	read_mmblob(&src1, &a->oid);
 	read_mmblob(&src2, &b->oid);
 
@@ -1295,7 +1295,7 @@ static int merge_submodule(struct merge_options *opt,
 }
 
 static int merge_mode_and_contents(struct merge_options *opt,
-				   const struct diff_filespec *one,
+				   const struct diff_filespec *o,
 				   const struct diff_filespec *a,
 				   const struct diff_filespec *b,
 				   const char *filename,
@@ -1310,7 +1310,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		 * side of the conflict markers and the other branch on the
 		 * top.  Fix that.
 		 */
-		return merge_mode_and_contents(opt, one, b, a,
+		return merge_mode_and_contents(opt, o, b, a,
 					       filename,
 					       branch2, branch1,
 					       extra_marker_size, result);
@@ -1329,31 +1329,31 @@ static int merge_mode_and_contents(struct merge_options *opt,
 			oidcpy(&result->oid, &b->oid);
 		}
 	} else {
-		if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
+		if (!oid_eq(&a->oid, &o->oid) && !oid_eq(&b->oid, &o->oid))
 			result->merge = 1;
 
 		/*
 		 * Merge modes
 		 */
-		if (a->mode == b->mode || a->mode == one->mode)
+		if (a->mode == b->mode || a->mode == o->mode)
 			result->mode = b->mode;
 		else {
 			result->mode = a->mode;
-			if (b->mode != one->mode) {
+			if (b->mode != o->mode) {
 				result->clean = 0;
 				result->merge = 1;
 			}
 		}
 
-		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
+		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &o->oid))
 			oidcpy(&result->oid, &b->oid);
-		else if (oid_eq(&b->oid, &one->oid))
+		else if (oid_eq(&b->oid, &o->oid))
 			oidcpy(&result->oid, &a->oid);
 		else if (S_ISREG(a->mode)) {
 			mmbuffer_t result_buf;
 			int ret = 0, merge_status;
 
-			merge_status = merge_3way(opt, &result_buf, one, a, b,
+			merge_status = merge_3way(opt, &result_buf, o, a, b,
 						  branch1, branch2,
 						  extra_marker_size);
 
@@ -1372,8 +1372,8 @@ static int merge_mode_and_contents(struct merge_options *opt,
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
 			result->clean = merge_submodule(opt, &result->oid,
-							one->path,
-							&one->oid,
+							o->path,
+							&o->oid,
 							&a->oid,
 							&b->oid);
 		} else if (S_ISLNK(a->mode)) {
@@ -1750,7 +1750,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	struct merge_file_info mfi;
 	struct diff_filespec other;
 	struct diff_filespec *add;
-	struct diff_filespec *one = ci->pair1->one;
+	struct diff_filespec *o = ci->pair1->one;
 	struct diff_filespec *a = ci->pair1->two;
 	struct diff_filespec *b = ci->pair2->two;
 	char *path_desc;
@@ -1758,13 +1758,13 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
-	       one->path, a->path, ci->branch1,
-	       one->path, b->path, ci->branch2,
+	       o->path, a->path, ci->branch1,
+	       o->path, b->path, ci->branch2,
 	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
-			    a->path, b->path, one->path);
-	if (merge_mode_and_contents(opt, one, a, b, path_desc,
+			    a->path, b->path, o->path);
+	if (merge_mode_and_contents(opt, o, a, b, path_desc,
 				    ci->branch1, ci->branch2,
 				    opt->call_depth * 2, &mfi))
 		return -1;
@@ -1777,7 +1777,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(opt, 0, &mfi.oid, mfi.mode, one->path))
+		if (update_file(opt, 0, &mfi.oid, mfi.mode, o->path))
 			return -1;
 
 		/*
@@ -2863,10 +2863,10 @@ static int process_renames(struct merge_options *opt,
 			if (clean_merge < 0)
 				goto cleanup_and_return;
 			if (try_merge) {
-				struct diff_filespec *one, *a, *b;
+				struct diff_filespec *o, *a, *b;
 				src_other.path = (char *)ren1_src;
 
-				one = ren1->pair->one;
+				o = ren1->pair->one;
 				if (a_renames == renames1) {
 					a = ren1->pair->two;
 					b = &src_other;
@@ -2874,7 +2874,7 @@ static int process_renames(struct merge_options *opt,
 					b = ren1->pair->two;
 					a = &src_other;
 				}
-				update_entry(ren1->dst_entry, one, a, b);
+				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
 							   ren1->pair,
 							   NULL,
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 04/15] merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'

[Elijah Newren]

Since we want to replace oid,mode pairs with a single diff_filespec,
we will soon want to be able to use the names 'o', 'a', and 'b' for
the three different file versions.  Rename some local variables in
blob_unchanged() that would otherwise conflict.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 36af5d9cc6..4ed1b48630 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3031,9 +3031,10 @@ static int blob_unchanged(struct merge_options *opt,
 			  unsigned a_mode,
 			  int renormalize, const char *path)
 {
-	struct strbuf o = STRBUF_INIT;
-	struct strbuf a = STRBUF_INIT;
+	struct strbuf obuf = STRBUF_INIT;
+	struct strbuf abuf = STRBUF_INIT;
 	int ret = 0; /* assume changed for safety */
+	const struct index_state *idx = opt->repo->index;
 
 	if (a_mode != o_mode)
 		return 0;
@@ -3043,20 +3044,21 @@ static int blob_unchanged(struct merge_options *opt,
 		return 0;
 
 	assert(o_oid && a_oid);
-	if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
+	if (read_oid_strbuf(opt, o_oid, &obuf) ||
+	    read_oid_strbuf(opt, a_oid, &abuf))
 		goto error_return;
 	/*
 	 * Note: binary | is used so that both renormalizations are
 	 * performed.  Comparison can be skipped if both files are
 	 * unchanged since their sha1s have already been compared.
 	 */
-	if (renormalize_buffer(opt->repo->index, path, o.buf, o.len, &o) |
-	    renormalize_buffer(opt->repo->index, path, a.buf, a.len, &a))
-		ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+	if (renormalize_buffer(idx, path, obuf.buf, obuf.len, &obuf) |
+	    renormalize_buffer(idx, path, abuf.buf, abuf.len, &abuf))
+		ret = (obuf.len == abuf.len && !memcmp(obuf.buf, abuf.buf, obuf.len));
 
 error_return:
-	strbuf_release(&o);
-	strbuf_release(&a);
+	strbuf_release(&obuf);
+	strbuf_release(&abuf);
 	return ret;
 }
 
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 05/15] merge-recursive: use 'ci' for rename_conflict_info variable name

[Elijah Newren]

We used a couple different names, but used 'ci' the most.  Use the same
variable name throughout for a little extra consistency.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 4ed1b48630..ea5646debd 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3098,7 +3098,7 @@ static int handle_content_merge(struct merge_options *opt,
 				struct object_id *o_oid, int o_mode,
 				struct object_id *a_oid, int a_mode,
 				struct object_id *b_oid, int b_mode,
-				struct rename_conflict_info *rename_conflict_info)
+				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
 	const char *path1 = NULL, *path2 = NULL;
@@ -3118,17 +3118,17 @@ static int handle_content_merge(struct merge_options *opt,
 	oidcpy(&b.oid, b_oid);
 	b.mode = b_mode;
 
-	if (rename_conflict_info) {
-		struct diff_filepair *pair1 = rename_conflict_info->pair1;
+	if (ci) {
+		struct diff_filepair *pair1 = ci->pair1;
 
-		path1 = (opt->branch1 == rename_conflict_info->branch1) ?
+		path1 = (opt->branch1 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
-		/* If rename_conflict_info->pair2 != NULL, we are in
+		/* If ci->pair2 != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
-		path2 = (rename_conflict_info->pair2 ||
-			 opt->branch2 == rename_conflict_info->branch1) ?
+		path2 = (ci->pair2 ||
+			 opt->branch2 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
 		a.path = (char *)path1;
@@ -3180,7 +3180,7 @@ static int handle_content_merge(struct merge_options *opt,
 			reason = _("submodule");
 		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
-		if (rename_conflict_info && !df_conflict_remains)
+		if (ci && !df_conflict_remains)
 			if (update_stages(opt, path, &one, &a, &b))
 				return -1;
 	}
@@ -3206,7 +3206,7 @@ static int handle_content_merge(struct merge_options *opt,
 			}
 
 		}
-		new_path = unique_path(opt, path, rename_conflict_info->branch1);
+		new_path = unique_path(opt, path, ci->branch1);
 		if (is_dirty) {
 			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
@@ -3251,8 +3251,8 @@ static int process_entry(struct merge_options *opt,
 
 	entry->processed = 1;
 	if (entry->rename_conflict_info) {
-		struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
-		switch (conflict_info->rename_type) {
+		struct rename_conflict_info *ci = entry->rename_conflict_info;
+		switch (ci->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
 			clean_merge = handle_rename_normal(opt,
@@ -3260,13 +3260,11 @@ static int process_entry(struct merge_options *opt,
 							   o_oid, o_mode,
 							   a_oid, a_mode,
 							   b_oid, b_mode,
-							   conflict_info);
+							   ci);
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt,
-						  conflict_info->pair1,
-						  conflict_info->branch1))
+			if (handle_rename_via_dir(opt, ci->pair1, ci->branch1))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3276,19 +3274,17 @@ static int process_entry(struct merge_options *opt,
 			 * two-way merged cleanly with the added file, I
 			 * guess it's a clean merge?
 			 */
-			clean_merge = handle_rename_add(opt, conflict_info);
+			clean_merge = handle_rename_add(opt, ci);
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(opt,
-						 conflict_info->pair1,
-						 conflict_info->branch1,
-						 conflict_info->branch2))
+			if (handle_rename_delete(opt, ci->pair1,
+						 ci->branch1, ci->branch2))
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
 			clean_merge = 0;
-			if (handle_rename_rename_1to2(opt, conflict_info))
+			if (handle_rename_rename_1to2(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_TWO_FILES_TO_ONE:
@@ -3298,8 +3294,7 @@ static int process_entry(struct merge_options *opt,
 			 * can then be two-way merged cleanly, I guess it's
 			 * a clean merge?
 			 */
-			clean_merge = handle_rename_rename_2to1(opt,
-								conflict_info);
+			clean_merge = handle_rename_rename_2to1(opt, ci);
 			break;
 		default:
 			entry->processed = 0;
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 06/15] merge-recursive: move some struct declarations together

[Elijah Newren]

These structs are related and reference each other, so move them
together to make it easier for folks to determine what they hold and
what their purpose is.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 78 +++++++++++++++++++++++------------------------
 1 file changed, 39 insertions(+), 39 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index ea5646debd..c4a2ef2a37 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -196,18 +196,6 @@ enum rename_type {
 	RENAME_TWO_FILES_TO_ONE
 };
 
-struct rename_conflict_info {
-	enum rename_type rename_type;
-	struct diff_filepair *pair1;
-	struct diff_filepair *pair2;
-	const char *branch1;
-	const char *branch2;
-	struct stage_data *dst_entry1;
-	struct stage_data *dst_entry2;
-	struct diff_filespec ren1_other;
-	struct diff_filespec ren2_other;
-};
-
 /*
  * Since we want to write the index eventually, we cannot reuse the index
  * for these (temporary) data.
@@ -221,6 +209,45 @@ struct stage_data {
 	unsigned processed:1;
 };
 
+struct rename {
+	struct diff_filepair *pair;
+	/*
+	 * Purpose of src_entry and dst_entry:
+	 *
+	 * If 'before' is renamed to 'after' then src_entry will contain
+	 * the versions of 'before' from the merge_base, HEAD, and MERGE in
+	 * stages 1, 2, and 3; dst_entry will contain the respective
+	 * versions of 'after' in corresponding locations.  Thus, we have a
+	 * total of six modes and oids, though some will be null.  (Stage 0
+	 * is ignored; we're interested in handling conflicts.)
+	 *
+	 * Since we don't turn on break-rewrites by default, neither
+	 * src_entry nor dst_entry can have all three of their stages have
+	 * non-null oids, meaning at most four of the six will be non-null.
+	 * Also, since this is a rename, both src_entry and dst_entry will
+	 * have at least one non-null oid, meaning at least two will be
+	 * non-null.  Of the six oids, a typical rename will have three be
+	 * non-null.  Only two implies a rename/delete, and four implies a
+	 * rename/add.
+	 */
+	struct stage_data *src_entry;
+	struct stage_data *dst_entry;
+	unsigned add_turned_into_rename:1;
+	unsigned processed:1;
+};
+
+struct rename_conflict_info {
+	enum rename_type rename_type;
+	struct diff_filepair *pair1;
+	struct diff_filepair *pair2;
+	const char *branch1;
+	const char *branch2;
+	struct stage_data *dst_entry1;
+	struct stage_data *dst_entry2;
+	struct diff_filespec ren1_other;
+	struct diff_filespec ren2_other;
+};
+
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      struct diff_filepair *pair1,
 					      struct diff_filepair *pair2,
@@ -645,33 +672,6 @@ static void record_df_conflict_files(struct merge_options *opt,
 	string_list_clear(&df_sorted_entries, 0);
 }
 
-struct rename {
-	struct diff_filepair *pair;
-	/*
-	 * Purpose of src_entry and dst_entry:
-	 *
-	 * If 'before' is renamed to 'after' then src_entry will contain
-	 * the versions of 'before' from the merge_base, HEAD, and MERGE in
-	 * stages 1, 2, and 3; dst_entry will contain the respective
-	 * versions of 'after' in corresponding locations.  Thus, we have a
-	 * total of six modes and oids, though some will be null.  (Stage 0
-	 * is ignored; we're interested in handling conflicts.)
-	 *
-	 * Since we don't turn on break-rewrites by default, neither
-	 * src_entry nor dst_entry can have all three of their stages have
-	 * non-null oids, meaning at most four of the six will be non-null.
-	 * Also, since this is a rename, both src_entry and dst_entry will
-	 * have at least one non-null oid, meaning at least two will be
-	 * non-null.  Of the six oids, a typical rename will have three be
-	 * non-null.  Only two implies a rename/delete, and four implies a
-	 * rename/add.
-	 */
-	struct stage_data *src_entry;
-	struct stage_data *dst_entry;
-	unsigned add_turned_into_rename:1;
-	unsigned processed:1;
-};
-
 static int update_stages(struct merge_options *opt, const char *path,
 			 const struct diff_filespec *o,
 			 const struct diff_filespec *a,
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 07/15] merge-recursive: shrink rename_conflict_info

[Elijah Newren]

The rename_conflict_info struct used both a pair and a stage_data which
were taken from a rename struct.  Just use the original rename struct.
This will also allow us to start making other simplifications to the
code.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 120 +++++++++++++++++++---------------------------
 1 file changed, 50 insertions(+), 70 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index c4a2ef2a37..e05f8f22f5 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -238,24 +238,20 @@ struct rename {
 
 struct rename_conflict_info {
 	enum rename_type rename_type;
-	struct diff_filepair *pair1;
-	struct diff_filepair *pair2;
+	struct rename *ren1;
+	struct rename *ren2;
 	const char *branch1;
 	const char *branch2;
-	struct stage_data *dst_entry1;
-	struct stage_data *dst_entry2;
 	struct diff_filespec ren1_other;
 	struct diff_filespec ren2_other;
 };
 
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
-					      struct diff_filepair *pair1,
-					      struct diff_filepair *pair2,
+					      struct merge_options *opt,
+					      struct rename *ren1,
+					      struct rename *ren2,
 					      const char *branch1,
 					      const char *branch2,
-					      struct stage_data *dst_entry1,
-					      struct stage_data *dst_entry2,
-					      struct merge_options *opt,
 					      struct stage_data *src_entry1,
 					      struct stage_data *src_entry2)
 {
@@ -269,31 +265,27 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (dst_entry2 && branch1 != opt->branch1) {
+	if (ren2 && branch1 != opt->branch1) {
 		setup_rename_conflict_info(rename_type,
-					   pair2,      pair1,
-					   branch2,    branch1,
-					   dst_entry2, dst_entry1,
 					   opt,
+					   ren2,       ren1,
+					   branch2,    branch1,
 					   src_entry2, src_entry1);
 		return;
 	}
 
 	ci = xcalloc(1, sizeof(struct rename_conflict_info));
 	ci->rename_type = rename_type;
-	ci->pair1 = pair1;
+	ci->ren1 = ren1;
+	ci->ren2 = ren2;
 	ci->branch1 = branch1;
 	ci->branch2 = branch2;
 
-	ci->dst_entry1 = dst_entry1;
-	dst_entry1->rename_conflict_info = ci;
-	dst_entry1->processed = 0;
+	ci->ren1->dst_entry->processed = 0;
+	ci->ren1->dst_entry->rename_conflict_info = ci;
 
-	assert(!pair2 == !dst_entry2);
-	if (dst_entry2) {
-		ci->dst_entry2 = dst_entry2;
-		ci->pair2 = pair2;
-		dst_entry2->rename_conflict_info = ci;
+	if (ren2) {
+		ci->ren2->dst_entry->rename_conflict_info = ci;
 	}
 
 	/*
@@ -305,7 +297,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	    rename_type == RENAME_TWO_FILES_TO_ONE) {
 		ostage1 = opt->branch1 == branch1 ? 3 : 2;
 
-		ci->ren1_other.path = pair1->one->path;
+		ci->ren1_other.path = ren1->pair->one->path;
 		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
 		ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 	}
@@ -313,7 +305,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 		ostage2 = ostage1 ^ 1;
 
-		ci->ren2_other.path = pair2->one->path;
+		ci->ren2_other.path = ren2->pair->one->path;
 		oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
 		ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 	}
@@ -1694,8 +1686,8 @@ static int handle_rename_add(struct merge_options *opt,
 			     struct rename_conflict_info *ci)
 {
 	/* a was renamed to c, and a separate c was added. */
-	struct diff_filespec *a = ci->pair1->one;
-	struct diff_filespec *c = ci->pair1->two;
+	struct diff_filespec *a = ci->ren1->pair->one;
+	struct diff_filespec *c = ci->ren1->pair->two;
 	char *path = c->path;
 	char *prev_path_desc;
 	struct merge_file_info mfi;
@@ -1718,8 +1710,8 @@ static int handle_rename_add(struct merge_options *opt,
 				     c->path, a->path, NULL,
 				     ci->branch1, ci->branch2,
 				     &mfi.oid, mfi.mode,
-				     &ci->dst_entry1->stages[other_stage].oid,
-				     ci->dst_entry1->stages[other_stage].mode);
+				     &ci->ren1->dst_entry->stages[other_stage].oid,
+				     ci->ren1->dst_entry->stages[other_stage].mode);
 }
 
 static char *find_path_for_conflict(struct merge_options *opt,
@@ -1750,9 +1742,9 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	struct merge_file_info mfi;
 	struct diff_filespec other;
 	struct diff_filespec *add;
-	struct diff_filespec *o = ci->pair1->one;
-	struct diff_filespec *a = ci->pair1->two;
-	struct diff_filespec *b = ci->pair2->two;
+	struct diff_filespec *o = ci->ren1->pair->one;
+	struct diff_filespec *a = ci->ren1->pair->two;
+	struct diff_filespec *b = ci->ren2->pair->two;
 	char *path_desc;
 
 	output(opt, 1, _("CONFLICT (rename/rename): "
@@ -1788,14 +1780,14 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * such cases, we should keep the added file around,
 		 * resolving the conflict at that path in its favor.
 		 */
-		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
+		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
 		if (add) {
 			if (update_file(opt, 0, &add->oid, add->mode, a->path))
 				return -1;
 		}
 		else
 			remove_file_from_index(opt->repo->index, a->path);
-		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
+		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
 		if (add) {
 			if (update_file(opt, 0, &add->oid, add->mode, b->path))
 				return -1;
@@ -1808,7 +1800,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * rename/add collision.  If not, we can write the file out
 		 * to the specified location.
 		 */
-		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
+		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
 		if (add) {
 			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
@@ -1827,7 +1819,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 				return -1;
 		}
 
-		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
+		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
 		if (add) {
 			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
@@ -1854,10 +1846,10 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 				     struct rename_conflict_info *ci)
 {
 	/* Two files, a & b, were renamed to the same thing, c. */
-	struct diff_filespec *a = ci->pair1->one;
-	struct diff_filespec *b = ci->pair2->one;
-	struct diff_filespec *c1 = ci->pair1->two;
-	struct diff_filespec *c2 = ci->pair2->two;
+	struct diff_filespec *a = ci->ren1->pair->one;
+	struct diff_filespec *b = ci->ren2->pair->one;
+	struct diff_filespec *c1 = ci->ren1->pair->two;
+	struct diff_filespec *c2 = ci->ren2->pair->two;
 	char *path = c1->path; /* == c2->path */
 	char *path_side_1_desc;
 	char *path_side_2_desc;
@@ -2732,13 +2724,11 @@ static int process_renames(struct merge_options *opt,
 					     ren2->pair->two);
 			}
 			setup_rename_conflict_info(rename_type,
-						   ren1->pair,
-						   ren2->pair,
+						   opt,
+						   ren1,
+						   ren2,
 						   branch1,
 						   branch2,
-						   ren1->dst_entry,
-						   ren2->dst_entry,
-						   opt,
 						   NULL,
 						   NULL);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
@@ -2759,13 +2749,11 @@ static int process_renames(struct merge_options *opt,
 			ren2->src_entry->processed = 1;
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
-						   ren1->pair,
-						   ren2->pair,
+						   opt,
+						   ren1,
+						   ren2,
 						   branch1,
 						   branch2,
-						   ren1->dst_entry,
-						   ren2->dst_entry,
-						   opt,
 						   ren1->src_entry,
 						   ren2->src_entry);
 
@@ -2802,24 +2790,20 @@ static int process_renames(struct merge_options *opt,
 			if (oid_eq(&src_other.oid, &null_oid) &&
 			    ren1->add_turned_into_rename) {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   NULL,
 							   NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   NULL,
 							   NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
@@ -2848,13 +2832,11 @@ static int process_renames(struct merge_options *opt,
 				 * file, then the merge will be clean.
 				 */
 				setup_rename_conflict_info(RENAME_ADD,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   ren1->src_entry,
 							   NULL);
 			} else
@@ -2876,13 +2858,11 @@ static int process_renames(struct merge_options *opt,
 				}
 				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
-							   ren1->pair,
+							   opt,
+							   ren1,
 							   NULL,
 							   branch1,
 							   NULL,
-							   ren1->dst_entry,
-							   NULL,
-							   opt,
 							   NULL,
 							   NULL);
 			}
@@ -3119,15 +3099,15 @@ static int handle_content_merge(struct merge_options *opt,
 	b.mode = b_mode;
 
 	if (ci) {
-		struct diff_filepair *pair1 = ci->pair1;
+		struct diff_filepair *pair1 = ci->ren1->pair;
 
 		path1 = (opt->branch1 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
-		/* If ci->pair2 != NULL, we are in
+		/* If ci->ren2->pair != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
-		path2 = (ci->pair2 ||
+		path2 = ((ci->ren2 && ci->ren2->pair) ||
 			 opt->branch2 == ci->branch1) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
@@ -3264,7 +3244,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci->pair1, ci->branch1))
+			if (handle_rename_via_dir(opt, ci->ren1->pair, ci->branch1))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3278,7 +3258,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(opt, ci->pair1,
+			if (handle_rename_delete(opt, ci->ren1->pair,
 						 ci->branch1, ci->branch2))
 				clean_merge = -1;
 			break;
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 08/15] merge-recursive: remove ren[12]_other fields from rename_conflict_info

[Elijah Newren]

The ren1_other and ren2_other fields were synthesized from information
in ren1->src_entry and ren2->src_entry.  Since we already have the
necessary information in ren1 and ren2, just use those.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 71 ++++++++++++++---------------------------------
 1 file changed, 21 insertions(+), 50 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index e05f8f22f5..e66b47cfa1 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -242,8 +242,6 @@ struct rename_conflict_info {
 	struct rename *ren2;
 	const char *branch1;
 	const char *branch2;
-	struct diff_filespec ren1_other;
-	struct diff_filespec ren2_other;
 };
 
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
@@ -251,11 +249,8 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      struct rename *ren1,
 					      struct rename *ren2,
 					      const char *branch1,
-					      const char *branch2,
-					      struct stage_data *src_entry1,
-					      struct stage_data *src_entry2)
+					      const char *branch2)
 {
-	int ostage1 = 0, ostage2;
 	struct rename_conflict_info *ci;
 
 	/*
@@ -269,8 +264,7 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 		setup_rename_conflict_info(rename_type,
 					   opt,
 					   ren2,       ren1,
-					   branch2,    branch1,
-					   src_entry2, src_entry1);
+					   branch2,    branch1);
 		return;
 	}
 
@@ -287,28 +281,6 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	if (ren2) {
 		ci->ren2->dst_entry->rename_conflict_info = ci;
 	}
-
-	/*
-	 * For each rename, there could have been
-	 * modifications on the side of history where that
-	 * file was not renamed.
-	 */
-	if (rename_type == RENAME_ADD ||
-	    rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage1 = opt->branch1 == branch1 ? 3 : 2;
-
-		ci->ren1_other.path = ren1->pair->one->path;
-		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
-		ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
-	}
-
-	if (rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage2 = ostage1 ^ 1;
-
-		ci->ren2_other.path = ren2->pair->one->path;
-		oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
-		ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
-	}
 }
 
 static int show(struct merge_options *opt, int v)
@@ -1688,6 +1660,7 @@ static int handle_rename_add(struct merge_options *opt,
 	/* a was renamed to c, and a separate c was added. */
 	struct diff_filespec *a = ci->ren1->pair->one;
 	struct diff_filespec *c = ci->ren1->pair->two;
+	struct diff_filespec tmp;
 	char *path = c->path;
 	char *prev_path_desc;
 	struct merge_file_info mfi;
@@ -1699,8 +1672,12 @@ static int handle_rename_add(struct merge_options *opt,
 	       a->path, c->path, ci->branch1,
 	       c->path, ci->branch2);
 
+	filespec_from_entry(&tmp, ci->ren1->src_entry, other_stage);
+	tmp.path = a->path;
+
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(opt, a, c, &ci->ren1_other, prev_path_desc,
+	if (merge_mode_and_contents(opt, a, c, &tmp,
+				    prev_path_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi))
 		return -1;
@@ -1850,6 +1827,7 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	struct diff_filespec *b = ci->ren2->pair->one;
 	struct diff_filespec *c1 = ci->ren1->pair->two;
 	struct diff_filespec *c2 = ci->ren2->pair->two;
+	struct diff_filespec tmp1, tmp2;
 	char *path = c1->path; /* == c2->path */
 	char *path_side_1_desc;
 	char *path_side_2_desc;
@@ -1862,12 +1840,17 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	       a->path, c1->path, ci->branch1,
 	       b->path, c2->path, ci->branch2);
 
+	filespec_from_entry(&tmp1, ci->ren1->src_entry, 3);
+	tmp1.path = a->path;
+	filespec_from_entry(&tmp2, ci->ren2->src_entry, 2);
+	tmp2.path = b->path;
+
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	if (merge_mode_and_contents(opt, a, c1, &ci->ren1_other, path_side_1_desc,
+	if (merge_mode_and_contents(opt, a, c1, &tmp1, path_side_1_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(opt, b, &ci->ren2_other, c2, path_side_2_desc,
+	    merge_mode_and_contents(opt, b, &tmp2, c2, path_side_2_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c2))
 		return -1;
@@ -2728,9 +2711,7 @@ static int process_renames(struct merge_options *opt,
 						   ren1,
 						   ren2,
 						   branch1,
-						   branch2,
-						   NULL,
-						   NULL);
+						   branch2);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
 			/* Two different files renamed to the same thing */
 			char *ren2_dst;
@@ -2753,9 +2734,7 @@ static int process_renames(struct merge_options *opt,
 						   ren1,
 						   ren2,
 						   branch1,
-						   branch2,
-						   ren1->src_entry,
-						   ren2->src_entry);
+						   branch2);
 
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
@@ -2794,18 +2773,14 @@ static int process_renames(struct merge_options *opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   branch2,
-							   NULL,
-							   NULL);
+							   branch2);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
 							   opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   branch2,
-							   NULL,
-							   NULL);
+							   branch2);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
 				   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
 				/*
@@ -2836,9 +2811,7 @@ static int process_renames(struct merge_options *opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   branch2,
-							   ren1->src_entry,
-							   NULL);
+							   branch2);
 			} else
 				try_merge = 1;
 
@@ -2862,8 +2835,6 @@ static int process_renames(struct merge_options *opt,
 							   ren1,
 							   NULL,
 							   branch1,
-							   NULL,
-							   NULL,
 							   NULL);
 			}
 		}
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 09/15] merge-recursive: track branch where rename occurred in rename struct

[Elijah Newren]

We previously tracked the branch associated with a rename in a separate
field in rename_conflict_info, but since it is directly associated with
the rename it makes more sense to move it into the rename struct.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 113 +++++++++++++++++-----------------------------
 1 file changed, 42 insertions(+), 71 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index e66b47cfa1..f85c276f35 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -211,6 +211,7 @@ struct stage_data {
 
 struct rename {
 	struct diff_filepair *pair;
+	const char *branch; /* branch that the rename occurred on */
 	/*
 	 * Purpose of src_entry and dst_entry:
 	 *
@@ -240,16 +241,12 @@ struct rename_conflict_info {
 	enum rename_type rename_type;
 	struct rename *ren1;
 	struct rename *ren2;
-	const char *branch1;
-	const char *branch2;
 };
 
 static inline void setup_rename_conflict_info(enum rename_type rename_type,
 					      struct merge_options *opt,
 					      struct rename *ren1,
-					      struct rename *ren2,
-					      const char *branch1,
-					      const char *branch2)
+					      struct rename *ren2)
 {
 	struct rename_conflict_info *ci;
 
@@ -260,11 +257,8 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (ren2 && branch1 != opt->branch1) {
-		setup_rename_conflict_info(rename_type,
-					   opt,
-					   ren2,       ren1,
-					   branch2,    branch1);
+	if (ren2 && ren1->branch != opt->branch1) {
+		setup_rename_conflict_info(rename_type, opt, ren2, ren1);
 		return;
 	}
 
@@ -272,8 +266,6 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 	ci->rename_type = rename_type;
 	ci->ren1 = ren1;
 	ci->ren2 = ren2;
-	ci->branch1 = branch1;
-	ci->branch2 = branch2;
 
 	ci->ren1->dst_entry->processed = 0;
 	ci->ren1->dst_entry->rename_conflict_info = ci;
@@ -1665,12 +1657,15 @@ static int handle_rename_add(struct merge_options *opt,
 	char *prev_path_desc;
 	struct merge_file_info mfi;
 
-	int other_stage = (ci->branch1 == opt->branch1 ? 3 : 2);
+	const char *rename_branch = ci->ren1->branch;
+	const char *add_branch = (opt->branch1 == rename_branch ?
+				  opt->branch2 : opt->branch1);
+	int other_stage = (ci->ren1->branch == opt->branch1 ? 3 : 2);
 
 	output(opt, 1, _("CONFLICT (rename/add): "
 	       "Rename %s->%s in %s.  Added %s in %s"),
-	       a->path, c->path, ci->branch1,
-	       c->path, ci->branch2);
+	       a->path, c->path, rename_branch,
+	       c->path, add_branch);
 
 	filespec_from_entry(&tmp, ci->ren1->src_entry, other_stage);
 	tmp.path = a->path;
@@ -1685,7 +1680,7 @@ static int handle_rename_add(struct merge_options *opt,
 
 	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
-				     ci->branch1, ci->branch2,
+				     rename_branch, add_branch,
 				     &mfi.oid, mfi.mode,
 				     &ci->ren1->dst_entry->stages[other_stage].oid,
 				     ci->ren1->dst_entry->stages[other_stage].mode);
@@ -1727,14 +1722,14 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
-	       o->path, a->path, ci->branch1,
-	       o->path, b->path, ci->branch2,
+	       o->path, a->path, ci->ren1->branch,
+	       o->path, b->path, ci->ren2->branch,
 	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
 			    a->path, b->path, o->path);
 	if (merge_mode_and_contents(opt, o, a, b, path_desc,
-				    ci->branch1, ci->branch2,
+				    ci->ren1->branch, ci->ren2->branch,
 				    opt->call_depth * 2, &mfi))
 		return -1;
 	free(path_desc);
@@ -1781,14 +1776,15 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		if (add) {
 			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
-						  ci->branch1, ci->branch2,
+						  ci->ren1->branch,
+						  ci->ren2->branch,
 						  &mfi.oid, mfi.mode,
 						  &add->oid, add->mode) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, a->path,
-								ci->branch1,
-								ci->branch2);
+								ci->ren1->branch,
+								ci->ren2->branch);
 			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
@@ -1800,14 +1796,15 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		if (add) {
 			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
-						  ci->branch1, ci->branch2,
+						  ci->ren1->branch,
+						  ci->ren2->branch,
 						  &add->oid, add->mode,
 						  &mfi.oid, mfi.mode) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, b->path,
-								ci->branch2,
-								ci->branch1);
+								ci->ren2->branch,
+								ci->ren1->branch);
 			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
 				return -1;
 			free(new_path);
@@ -1837,8 +1834,8 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
 	       "Rename %s->%s in %s"),
-	       a->path, c1->path, ci->branch1,
-	       b->path, c2->path, ci->branch2);
+	       a->path, c1->path, ci->ren1->branch,
+	       b->path, c2->path, ci->ren2->branch);
 
 	filespec_from_entry(&tmp1, ci->ren1->src_entry, 3);
 	tmp1.path = a->path;
@@ -1858,7 +1855,7 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	free(path_side_2_desc);
 
 	return handle_file_collision(opt, path, a->path, b->path,
-				     ci->branch1, ci->branch2,
+				     ci->ren1->branch, ci->ren2->branch,
 				     &mfi_c1.oid, mfi_c1.mode,
 				     &mfi_c2.oid, mfi_c2.mode);
 }
@@ -2542,6 +2539,7 @@ static void apply_directory_rename_modifications(struct merge_options *opt,
  * information; tree is always equal to either a_tree or b_tree.
  */
 static struct string_list *get_renames(struct merge_options *opt,
+				       const char *branch,
 				       struct diff_queue_struct *pairs,
 				       struct hashmap *dir_renames,
 				       struct hashmap *dir_rename_exclusions,
@@ -2585,6 +2583,7 @@ static struct string_list *get_renames(struct merge_options *opt,
 		re->processed = 0;
 		re->add_turned_into_rename = 0;
 		re->pair = pair;
+		re->branch = branch;
 		item = string_list_lookup(entries, re->pair->one->path);
 		if (!item)
 			re->src_entry = insert_stage_data(re->pair->one->path,
@@ -2639,7 +2638,6 @@ static int process_renames(struct merge_options *opt,
 	for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 		struct string_list *renames1, *renames2Dst;
 		struct rename *ren1 = NULL, *ren2 = NULL;
-		const char *branch1, *branch2;
 		const char *ren1_src, *ren1_dst;
 		struct string_list_item *lookup;
 
@@ -2660,13 +2658,9 @@ static int process_renames(struct merge_options *opt,
 		if (ren1) {
 			renames1 = a_renames;
 			renames2Dst = &b_by_dst;
-			branch1 = opt->branch1;
-			branch2 = opt->branch2;
 		} else {
 			renames1 = b_renames;
 			renames2Dst = &a_by_dst;
-			branch1 = opt->branch2;
-			branch2 = opt->branch1;
 			SWAP(ren2, ren1);
 		}
 
@@ -2706,12 +2700,7 @@ static int process_renames(struct merge_options *opt,
 					     ren1->pair->two,
 					     ren2->pair->two);
 			}
-			setup_rename_conflict_info(rename_type,
-						   opt,
-						   ren1,
-						   ren2,
-						   branch1,
-						   branch2);
+			setup_rename_conflict_info(rename_type, opt, ren1, ren2);
 		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
 			/* Two different files renamed to the same thing */
 			char *ren2_dst;
@@ -2730,11 +2719,7 @@ static int process_renames(struct merge_options *opt,
 			ren2->src_entry->processed = 1;
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
-						   opt,
-						   ren1,
-						   ren2,
-						   branch1,
-						   branch2);
+						   opt, ren1, ren2);
 
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
@@ -2769,18 +2754,10 @@ static int process_renames(struct merge_options *opt,
 			if (oid_eq(&src_other.oid, &null_oid) &&
 			    ren1->add_turned_into_rename) {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   branch2);
+							   opt, ren1, NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   branch2);
+							   opt, ren1, NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
 				   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
 				/*
@@ -2807,11 +2784,7 @@ static int process_renames(struct merge_options *opt,
 				 * file, then the merge will be clean.
 				 */
 				setup_rename_conflict_info(RENAME_ADD,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   branch2);
+							   opt, ren1, NULL);
 			} else
 				try_merge = 1;
 
@@ -2831,11 +2804,7 @@ static int process_renames(struct merge_options *opt,
 				}
 				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
-							   opt,
-							   ren1,
-							   NULL,
-							   branch1,
-							   NULL);
+							   opt, ren1, NULL);
 			}
 		}
 	}
@@ -2904,13 +2873,13 @@ static int detect_and_process_renames(struct merge_options *opt,
 		dir_rename_init(dir_re_merge);
 	}
 
-	ri->head_renames  = get_renames(opt, head_pairs,
+	ri->head_renames  = get_renames(opt, opt->branch1, head_pairs,
 					dir_re_merge, dir_re_head, head,
 					common, head, merge, entries,
 					&clean);
 	if (clean < 0)
 		goto cleanup;
-	ri->merge_renames = get_renames(opt, merge_pairs,
+	ri->merge_renames = get_renames(opt, opt->branch2, merge_pairs,
 					dir_re_head, dir_re_merge, merge,
 					common, head, merge, entries,
 					&clean);
@@ -3072,14 +3041,14 @@ static int handle_content_merge(struct merge_options *opt,
 	if (ci) {
 		struct diff_filepair *pair1 = ci->ren1->pair;
 
-		path1 = (opt->branch1 == ci->branch1) ?
+		path1 = (opt->branch1 == ci->ren1->branch) ?
 			pair1->two->path : pair1->one->path;
 		/* If ci->ren2->pair != NULL, we are in
 		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
 		 * normal rename.
 		 */
 		path2 = ((ci->ren2 && ci->ren2->pair) ||
-			 opt->branch2 == ci->branch1) ?
+			 opt->branch2 == ci->ren1->branch) ?
 			pair1->two->path : pair1->one->path;
 		one.path = pair1->one->path;
 		a.path = (char *)path1;
@@ -3157,7 +3126,7 @@ static int handle_content_merge(struct merge_options *opt,
 			}
 
 		}
-		new_path = unique_path(opt, path, ci->branch1);
+		new_path = unique_path(opt, path, ci->ren1->branch);
 		if (is_dirty) {
 			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
@@ -3215,7 +3184,8 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci->ren1->pair, ci->branch1))
+			if (handle_rename_via_dir(opt, ci->ren1->pair,
+						  ci->ren1->branch))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3230,7 +3200,8 @@ static int process_entry(struct merge_options *opt,
 		case RENAME_DELETE:
 			clean_merge = 0;
 			if (handle_rename_delete(opt, ci->ren1->pair,
-						 ci->branch1, ci->branch2))
+						 ci->ren1->branch,
+						 ci->ren1->branch == opt->branch1 ? opt->branch2 : opt->branch1))
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 10/15] merge-recursive: cleanup handle_rename_* function signatures

[Elijah Newren]

Instead of passing various bits and pieces of 'ci', just pass it
directly.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index f85c276f35..ada1c19ed2 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1357,8 +1357,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 }
 
 static int handle_rename_via_dir(struct merge_options *opt,
-				 struct diff_filepair *pair,
-				 const char *rename_branch)
+				 struct rename_conflict_info *ci)
 {
 	/*
 	 * Handle file adds that need to be renamed due to directory rename
@@ -1366,10 +1365,11 @@ static int handle_rename_via_dir(struct merge_options *opt,
 	 * there is no content merge to do; just move the file into the
 	 * desired final location.
 	 */
-	const struct diff_filespec *dest = pair->two;
+	const struct rename *ren = ci->ren1;
+	const struct diff_filespec *dest = ren->pair->two;
 
 	if (!opt->call_depth && would_lose_untracked(opt, dest->path)) {
-		char *alt_path = unique_path(opt, dest->path, rename_branch);
+		char *alt_path = unique_path(opt, dest->path, ren->branch);
 
 		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
 			       "writing to %s instead."),
@@ -1383,8 +1383,8 @@ static int handle_rename_via_dir(struct merge_options *opt,
 			return -1;
 		free(alt_path);
 		return update_stages(opt, dest->path, NULL,
-				     rename_branch == opt->branch1 ? dest : NULL,
-				     rename_branch == opt->branch1 ? NULL : dest);
+				     ren->branch == opt->branch1 ? dest : NULL,
+				     ren->branch == opt->branch1 ? NULL : dest);
 	}
 
 	/* Update dest->path both in index and in worktree */
@@ -1476,12 +1476,14 @@ static int handle_change_delete(struct merge_options *opt,
 }
 
 static int handle_rename_delete(struct merge_options *opt,
-				struct diff_filepair *pair,
-				const char *rename_branch,
-				const char *delete_branch)
+				struct rename_conflict_info *ci)
 {
-	const struct diff_filespec *orig = pair->one;
-	const struct diff_filespec *dest = pair->two;
+	const struct rename *ren = ci->ren1;
+	const struct diff_filespec *orig = ren->pair->one;
+	const struct diff_filespec *dest = ren->pair->two;
+	const char *rename_branch = ren->branch;
+	const char *delete_branch = (opt->branch1 == ren->branch ?
+				     opt->branch2 : opt->branch1);
 
 	if (handle_change_delete(opt,
 				 opt->call_depth ? orig->path : dest->path,
@@ -3184,8 +3186,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_VIA_DIR:
 			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci->ren1->pair,
-						  ci->ren1->branch))
+			if (handle_rename_via_dir(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_ADD:
@@ -3199,9 +3200,7 @@ static int process_entry(struct merge_options *opt,
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(opt, ci->ren1->pair,
-						 ci->ren1->branch,
-						 ci->ren1->branch == opt->branch1 ? opt->branch2 : opt->branch1))
+			if (handle_rename_delete(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 11/15] merge-recursive: switch from (oid,mode) pairs to a diff_filespec

[Elijah Newren]

There was a significant inconsistency in the various parts of the API
used in merge-recursive; many places used a pair of (oid, mode) to track
file version/contents, while other parts used a diff_filespec (which
have an oid and mode embedded in it).  This inconsistency caused lots of
places to need to pack and unpack data to call into other functions.
This has been the subject of some past cleanups (see e.g. commit
0270a07ad0b2 ("merge-recursive: remove final remaining caller of
merge_file_one()", 2018-09-19)), but let's just remove the underlying
mess altogether by switching to use diff_filespec.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 483 +++++++++++++++++++++-------------------------
 1 file changed, 215 insertions(+), 268 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index ada1c19ed2..1d2c9e1772 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -201,10 +201,7 @@ enum rename_type {
  * for these (temporary) data.
  */
 struct stage_data {
-	struct {
-		unsigned short mode;
-		struct object_id oid;
-	} stages[4];
+	struct diff_filespec stages[4]; /* mostly for oid & mode; maybe path */
 	struct rename_conflict_info *rename_conflict_info;
 	unsigned processed:1;
 };
@@ -269,7 +266,6 @@ static inline void setup_rename_conflict_info(enum rename_type rename_type,
 
 	ci->ren1->dst_entry->processed = 0;
 	ci->ren1->dst_entry->rename_conflict_info = ci;
-
 	if (ren2) {
 		ci->ren2->dst_entry->rename_conflict_info = ci;
 	}
@@ -326,14 +322,14 @@ static void output_commit_title(struct merge_options *opt, struct commit *commit
 }
 
 static int add_cacheinfo(struct merge_options *opt,
-			 unsigned int mode, const struct object_id *oid,
+			 const struct diff_filespec *blob,
 			 const char *path, int stage, int refresh, int options)
 {
 	struct index_state *istate = opt->repo->index;
 	struct cache_entry *ce;
 	int ret;
 
-	ce = make_cache_entry(istate, mode, oid ? oid : &null_oid, path, stage, 0);
+	ce = make_cache_entry(istate, blob->mode, &blob->oid, path, stage, 0);
 	if (!ce)
 		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
@@ -464,15 +460,14 @@ static void get_files_dirs(struct merge_options *opt, struct tree *tree)
 
 static int get_tree_entry_if_blob(const struct object_id *tree,
 				  const char *path,
-				  struct object_id *hashy,
-				  unsigned short *mode_o)
+				  struct diff_filespec *dfs)
 {
 	int ret;
 
-	ret = get_tree_entry(tree, path, hashy, mode_o);
-	if (S_ISDIR(*mode_o)) {
-		oidcpy(hashy, &null_oid);
-		*mode_o = 0;
+	ret = get_tree_entry(tree, path, &dfs->oid, &dfs->mode);
+	if (S_ISDIR(dfs->mode)) {
+		oidcpy(&dfs->oid, &null_oid);
+		dfs->mode = 0;
 	}
 	return ret;
 }
@@ -487,12 +482,9 @@ static struct stage_data *insert_stage_data(const char *path,
 {
 	struct string_list_item *item;
 	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
-	get_tree_entry_if_blob(&o->object.oid, path,
-			       &e->stages[1].oid, &e->stages[1].mode);
-	get_tree_entry_if_blob(&a->object.oid, path,
-			       &e->stages[2].oid, &e->stages[2].mode);
-	get_tree_entry_if_blob(&b->object.oid, path,
-			       &e->stages[3].oid, &e->stages[3].mode);
+	get_tree_entry_if_blob(&o->object.oid, path, &e->stages[1]);
+	get_tree_entry_if_blob(&a->object.oid, path, &e->stages[2]);
+	get_tree_entry_if_blob(&b->object.oid, path, &e->stages[3]);
 	item = string_list_insert(entries, path);
 	item->util = e;
 	return e;
@@ -648,13 +640,13 @@ static int update_stages(struct merge_options *opt, const char *path,
 		if (remove_file_from_index(opt->repo->index, path))
 			return -1;
 	if (o)
-		if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
+		if (add_cacheinfo(opt, o, path, 1, 0, options))
 			return -1;
 	if (a)
-		if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
+		if (add_cacheinfo(opt, a, path, 2, 0, options))
 			return -1;
 	if (b)
-		if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
+		if (add_cacheinfo(opt, b, path, 3, 0, options))
 			return -1;
 	return 0;
 }
@@ -767,7 +759,7 @@ static int dir_in_way(struct index_state *istate, const char *path,
  * and its oid and mode match the specified values
  */
 static int was_tracked_and_matches(struct merge_options *opt, const char *path,
-				   const struct object_id *oid, unsigned mode)
+				   const struct diff_filespec *blob)
 {
 	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 	struct cache_entry *ce;
@@ -778,7 +770,7 @@ static int was_tracked_and_matches(struct merge_options *opt, const char *path,
 
 	/* See if the file we were tracking before matches */
 	ce = opt->orig_index.cache[pos];
-	return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
+	return (oid_eq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
 }
 
 /*
@@ -903,8 +895,7 @@ static int make_room_for_path(struct merge_options *opt, const char *path)
 }
 
 static int update_file_flags(struct merge_options *opt,
-			     const struct object_id *oid,
-			     unsigned mode,
+			     const struct diff_filespec *contents,
 			     const char *path,
 			     int update_cache,
 			     int update_wd)
@@ -919,7 +910,7 @@ static int update_file_flags(struct merge_options *opt,
 		void *buf;
 		unsigned long size;
 
-		if (S_ISGITLINK(mode)) {
+		if (S_ISGITLINK(contents->mode)) {
 			/*
 			 * We may later decide to recursively descend into
 			 * the submodule directory and update its index
@@ -929,14 +920,16 @@ static int update_file_flags(struct merge_options *opt,
 			goto update_index;
 		}
 
-		buf = read_object_file(oid, &type, &size);
+		buf = read_object_file(&contents->oid, &type, &size);
 		if (!buf)
-			return err(opt, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
+			return err(opt, _("cannot read object %s '%s'"),
+				   oid_to_hex(&contents->oid), path);
 		if (type != OBJ_BLOB) {
-			ret = err(opt, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
+			ret = err(opt, _("blob expected for %s '%s'"),
+				  oid_to_hex(&contents->oid), path);
 			goto free_buf;
 		}
-		if (S_ISREG(mode)) {
+		if (S_ISREG(contents->mode)) {
 			struct strbuf strbuf = STRBUF_INIT;
 			if (convert_to_working_tree(opt->repo->index, path, buf, size, &strbuf)) {
 				free(buf);
@@ -949,12 +942,11 @@ static int update_file_flags(struct merge_options *opt,
 			update_wd = 0;
 			goto free_buf;
 		}
-		if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
+		if (S_ISREG(contents->mode) ||
+		    (!has_symlinks && S_ISLNK(contents->mode))) {
 			int fd;
-			if (mode & 0100)
-				mode = 0777;
-			else
-				mode = 0666;
+			int mode = (contents->mode & 0100 ? 0777 : 0666);
+
 			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 			if (fd < 0) {
 				ret = err(opt, _("failed to open '%s': %s"),
@@ -963,7 +955,7 @@ static int update_file_flags(struct merge_options *opt,
 			}
 			write_in_full(fd, buf, size);
 			close(fd);
-		} else if (S_ISLNK(mode)) {
+		} else if (S_ISLNK(contents->mode)) {
 			char *lnk = xmemdupz(buf, size);
 			safe_create_leading_directories_const(path);
 			unlink(path);
@@ -974,13 +966,13 @@ static int update_file_flags(struct merge_options *opt,
 		} else
 			ret = err(opt,
 				  _("do not know what to do with %06o %s '%s'"),
-				  mode, oid_to_hex(oid), path);
+				  contents->mode, oid_to_hex(&contents->oid), path);
 	free_buf:
 		free(buf);
 	}
 update_index:
 	if (!ret && update_cache)
-		if (add_cacheinfo(opt, mode, oid, path, 0, update_wd,
+		if (add_cacheinfo(opt, contents, path, 0, update_wd,
 				  ADD_CACHE_OK_TO_ADD))
 			return -1;
 	return ret;
@@ -988,18 +980,17 @@ static int update_file_flags(struct merge_options *opt,
 
 static int update_file(struct merge_options *opt,
 		       int clean,
-		       const struct object_id *oid,
-		       unsigned mode,
+		       const struct diff_filespec *contents,
 		       const char *path)
 {
-	return update_file_flags(opt, oid, mode, path, opt->call_depth || clean, !opt->call_depth);
+	return update_file_flags(opt, contents, path,
+				 opt->call_depth || clean, !opt->call_depth);
 }
 
 /* Low level file merging, update and removal */
 
 struct merge_file_info {
-	struct object_id oid;
-	unsigned mode;
+	struct diff_filespec blob; /* mostly use oid & mode; sometimes path */
 	unsigned clean:1,
 		 merge:1;
 };
@@ -1039,6 +1030,7 @@ static int merge_3way(struct merge_options *opt,
 		}
 	}
 
+	assert(a->path && b->path);
 	if (strcmp(a->path, b->path) ||
 	    (opt->ancestor != NULL && strcmp(a->path, o->path) != 0)) {
 		base_name = opt->ancestor == NULL ? NULL :
@@ -1140,6 +1132,11 @@ static void print_commit(struct commit *commit)
 	strbuf_release(&sb);
 }
 
+static int is_valid(const struct diff_filespec *dfs)
+{
+	return dfs->mode != 0 && !is_null_oid(&dfs->oid);
+}
+
 static int merge_submodule(struct merge_options *opt,
 			   struct object_id *result, const char *path,
 			   const struct object_id *base, const struct object_id *a,
@@ -1278,11 +1275,11 @@ static int merge_mode_and_contents(struct merge_options *opt,
 	if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 		result->clean = 0;
 		if (S_ISREG(a->mode)) {
-			result->mode = a->mode;
-			oidcpy(&result->oid, &a->oid);
+			result->blob.mode = a->mode;
+			oidcpy(&result->blob.oid, &a->oid);
 		} else {
-			result->mode = b->mode;
-			oidcpy(&result->oid, &b->oid);
+			result->blob.mode = b->mode;
+			oidcpy(&result->blob.oid, &b->oid);
 		}
 	} else {
 		if (!oid_eq(&a->oid, &o->oid) && !oid_eq(&b->oid, &o->oid))
@@ -1292,9 +1289,9 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		 * Merge modes
 		 */
 		if (a->mode == b->mode || a->mode == o->mode)
-			result->mode = b->mode;
+			result->blob.mode = b->mode;
 		else {
-			result->mode = a->mode;
+			result->blob.mode = a->mode;
 			if (b->mode != o->mode) {
 				result->clean = 0;
 				result->merge = 1;
@@ -1302,9 +1299,9 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		}
 
 		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &o->oid))
-			oidcpy(&result->oid, &b->oid);
+			oidcpy(&result->blob.oid, &b->oid);
 		else if (oid_eq(&b->oid, &o->oid))
-			oidcpy(&result->oid, &a->oid);
+			oidcpy(&result->blob.oid, &a->oid);
 		else if (S_ISREG(a->mode)) {
 			mmbuffer_t result_buf;
 			int ret = 0, merge_status;
@@ -1318,7 +1315,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 
 			if (!ret &&
 			    write_object_file(result_buf.ptr, result_buf.size,
-					      blob_type, &result->oid))
+					      blob_type, &result->blob.oid))
 				ret = err(opt, _("Unable to add %s to database"),
 					  a->path);
 
@@ -1327,7 +1324,7 @@ static int merge_mode_and_contents(struct merge_options *opt,
 				return ret;
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(opt, &result->oid,
+			result->clean = merge_submodule(opt, &result->blob.oid,
 							o->path,
 							&o->oid,
 							&a->oid,
@@ -1335,15 +1332,15 @@ static int merge_mode_and_contents(struct merge_options *opt,
 		} else if (S_ISLNK(a->mode)) {
 			switch (opt->recursive_variant) {
 			case MERGE_RECURSIVE_NORMAL:
-				oidcpy(&result->oid, &a->oid);
+				oidcpy(&result->blob.oid, &a->oid);
 				if (!oid_eq(&a->oid, &b->oid))
 					result->clean = 0;
 				break;
 			case MERGE_RECURSIVE_OURS:
-				oidcpy(&result->oid, &a->oid);
+				oidcpy(&result->blob.oid, &a->oid);
 				break;
 			case MERGE_RECURSIVE_THEIRS:
-				oidcpy(&result->oid, &b->oid);
+				oidcpy(&result->blob.oid, &b->oid);
 				break;
 			}
 		} else
@@ -1379,7 +1376,7 @@ static int handle_rename_via_dir(struct merge_options *opt,
 		 * index.  Instead, write to dest->path for the index but
 		 * only at the higher appropriate stage.
 		 */
-		if (update_file(opt, 0, &dest->oid, dest->mode, alt_path))
+		if (update_file(opt, 0, dest, alt_path))
 			return -1;
 		free(alt_path);
 		return update_stages(opt, dest->path, NULL,
@@ -1388,16 +1385,15 @@ static int handle_rename_via_dir(struct merge_options *opt,
 	}
 
 	/* Update dest->path both in index and in worktree */
-	if (update_file(opt, 1, &dest->oid, dest->mode, dest->path))
+	if (update_file(opt, 1, dest, dest->path))
 		return -1;
 	return 0;
 }
 
 static int handle_change_delete(struct merge_options *opt,
 				const char *path, const char *old_path,
-				const struct object_id *o_oid, int o_mode,
-				const struct object_id *changed_oid,
-				int changed_mode,
+				const struct diff_filespec *o,
+				const struct diff_filespec *changed,
 				const char *change_branch,
 				const char *delete_branch,
 				const char *change, const char *change_past)
@@ -1419,7 +1415,7 @@ static int handle_change_delete(struct merge_options *opt,
 		 */
 		ret = remove_file_from_index(opt->repo->index, path);
 		if (!ret)
-			ret = update_file(opt, 0, o_oid, o_mode, update_path);
+			ret = update_file(opt, 0, o, update_path);
 	} else {
 		/*
 		 * Despite the four nearly duplicate messages and argument
@@ -1468,7 +1464,7 @@ static int handle_change_delete(struct merge_options *opt,
 		 * and update_wd=0, but that's a no-op.
 		 */
 		if (change_branch != opt->branch1 || alt_path)
-			ret = update_file(opt, 0, changed_oid, changed_mode, update_path);
+			ret = update_file(opt, 0, changed, update_path);
 	}
 	free(alt_path);
 
@@ -1488,8 +1484,7 @@ static int handle_rename_delete(struct merge_options *opt,
 	if (handle_change_delete(opt,
 				 opt->call_depth ? orig->path : dest->path,
 				 opt->call_depth ? NULL : orig->path,
-				 &orig->oid, orig->mode,
-				 &dest->oid, dest->mode,
+				 orig, dest,
 				 rename_branch, delete_branch,
 				 _("rename"), _("renamed")))
 		return -1;
@@ -1502,31 +1497,16 @@ static int handle_rename_delete(struct merge_options *opt,
 				     rename_branch == opt->branch1 ? NULL : dest);
 }
 
-static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
-						 struct stage_data *entry,
-						 int stage)
-{
-	struct object_id *oid = &entry->stages[stage].oid;
-	unsigned mode = entry->stages[stage].mode;
-	if (mode == 0 || is_null_oid(oid))
-		return NULL;
-	oidcpy(&target->oid, oid);
-	target->mode = mode;
-	return target;
-}
-
 static int handle_file_collision(struct merge_options *opt,
 				 const char *collide_path,
 				 const char *prev_path1,
 				 const char *prev_path2,
 				 const char *branch1, const char *branch2,
-				 const struct object_id *a_oid,
-				 unsigned int a_mode,
-				 const struct object_id *b_oid,
-				 unsigned int b_mode)
+				 struct diff_filespec *a,
+				 struct diff_filespec *b)
 {
 	struct merge_file_info mfi;
-	struct diff_filespec null, a, b;
+	struct diff_filespec null;
 	char *alt_path = NULL;
 	const char *update_path = collide_path;
 
@@ -1540,29 +1520,28 @@ static int handle_file_collision(struct merge_options *opt,
 		return handle_file_collision(opt, collide_path,
 					     prev_path2, prev_path1,
 					     branch2, branch1,
-					     b_oid, b_mode,
-					     a_oid, a_mode);
+					     b, a);
 	}
 
 	/*
 	 * In the recursive case, we just opt to undo renames
 	 */
 	if (opt->call_depth && (prev_path1 || prev_path2)) {
-		/* Put first file (a_oid, a_mode) in its original spot */
+		/* Put first file (a->oid, a->mode) in its original spot */
 		if (prev_path1) {
-			if (update_file(opt, 1, a_oid, a_mode, prev_path1))
+			if (update_file(opt, 1, a, prev_path1))
 				return -1;
 		} else {
-			if (update_file(opt, 1, a_oid, a_mode, collide_path))
+			if (update_file(opt, 1, a, collide_path))
 				return -1;
 		}
 
-		/* Put second file (b_oid, b_mode) in its original spot */
+		/* Put second file (b->oid, b->mode) in its original spot */
 		if (prev_path2) {
-			if (update_file(opt, 1, b_oid, b_mode, prev_path2))
+			if (update_file(opt, 1, b, prev_path2))
 				return -1;
 		} else {
-			if (update_file(opt, 1, b_oid, b_mode, collide_path))
+			if (update_file(opt, 1, b, collide_path))
 				return -1;
 		}
 
@@ -1616,26 +1595,18 @@ static int handle_file_collision(struct merge_options *opt,
 	}
 
 	/* Store things in diff_filespecs for functions that need it */
-	memset(&a, 0, sizeof(struct diff_filespec));
-	memset(&b, 0, sizeof(struct diff_filespec));
-	null.path = a.path = b.path = (char *)collide_path;
+	null.path = (char *)collide_path;
 	oidcpy(&null.oid, &null_oid);
 	null.mode = 0;
-	oidcpy(&a.oid, a_oid);
-	a.mode = a_mode;
-	a.oid_valid = 1;
-	oidcpy(&b.oid, b_oid);
-	b.mode = b_mode;
-	b.oid_valid = 1;
-
-	if (merge_mode_and_contents(opt, &null, &a, &b, collide_path,
+
+	if (merge_mode_and_contents(opt, &null, a, b, collide_path,
 				    branch1, branch2, opt->call_depth * 2, &mfi))
 		return -1;
 	mfi.clean &= !alt_path;
-	if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, update_path))
+	if (update_file(opt, mfi.clean, &mfi.blob, update_path))
 		return -1;
 	if (!mfi.clean && !opt->call_depth &&
-	    update_stages(opt, collide_path, NULL, &a, &b))
+	    update_stages(opt, collide_path, NULL, a, b))
 		return -1;
 	free(alt_path);
 	/*
@@ -1654,7 +1625,6 @@ static int handle_rename_add(struct merge_options *opt,
 	/* a was renamed to c, and a separate c was added. */
 	struct diff_filespec *a = ci->ren1->pair->one;
 	struct diff_filespec *c = ci->ren1->pair->two;
-	struct diff_filespec tmp;
 	char *path = c->path;
 	char *prev_path_desc;
 	struct merge_file_info mfi;
@@ -1669,23 +1639,21 @@ static int handle_rename_add(struct merge_options *opt,
 	       a->path, c->path, rename_branch,
 	       c->path, add_branch);
 
-	filespec_from_entry(&tmp, ci->ren1->src_entry, other_stage);
-	tmp.path = a->path;
-
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(opt, a, c, &tmp,
+	if (merge_mode_and_contents(opt, a, c,
+				    &ci->ren1->src_entry->stages[other_stage],
 				    prev_path_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi))
 		return -1;
 	free(prev_path_desc);
 
+	ci->ren1->dst_entry->stages[other_stage].path = mfi.blob.path = c->path;
 	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
 				     rename_branch, add_branch,
-				     &mfi.oid, mfi.mode,
-				     &ci->ren1->dst_entry->stages[other_stage].oid,
-				     ci->ren1->dst_entry->stages[other_stage].mode);
+				     &mfi.blob,
+				     &ci->ren1->dst_entry->stages[other_stage]);
 }
 
 static char *find_path_for_conflict(struct merge_options *opt,
@@ -1714,7 +1682,6 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 {
 	/* One file was renamed in both branches, but to different names. */
 	struct merge_file_info mfi;
-	struct diff_filespec other;
 	struct diff_filespec *add;
 	struct diff_filespec *o = ci->ren1->pair->one;
 	struct diff_filespec *a = ci->ren1->pair->two;
@@ -1743,7 +1710,7 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(opt, 0, &mfi.oid, mfi.mode, o->path))
+		if (update_file(opt, 0, &mfi.blob, o->path))
 			return -1;
 
 		/*
@@ -1754,16 +1721,16 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * such cases, we should keep the added file around,
 		 * resolving the conflict at that path in its favor.
 		 */
-		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
-		if (add) {
-			if (update_file(opt, 0, &add->oid, add->mode, a->path))
+		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		if (is_valid(add)) {
+			if (update_file(opt, 0, add, a->path))
 				return -1;
 		}
 		else
 			remove_file_from_index(opt->repo->index, a->path);
-		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
-		if (add) {
-			if (update_file(opt, 0, &add->oid, add->mode, b->path))
+		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		if (is_valid(add)) {
+			if (update_file(opt, 0, add, b->path))
 				return -1;
 		}
 		else
@@ -1774,40 +1741,42 @@ static int handle_rename_rename_1to2(struct merge_options *opt,
 		 * rename/add collision.  If not, we can write the file out
 		 * to the specified location.
 		 */
-		add = filespec_from_entry(&other, ci->ren1->dst_entry, 2 ^ 1);
-		if (add) {
+		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		if (is_valid(add)) {
+			add->path = mfi.blob.path = a->path;
 			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
 						  ci->ren1->branch,
 						  ci->ren2->branch,
-						  &mfi.oid, mfi.mode,
-						  &add->oid, add->mode) < 0)
+						  &mfi.blob, add) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, a->path,
 								ci->ren1->branch,
 								ci->ren2->branch);
-			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
+			if (update_file(opt, 0, &mfi.blob,
+					new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
 			if (update_stages(opt, a->path, NULL, a, NULL))
 				return -1;
 		}
 
-		add = filespec_from_entry(&other, ci->ren2->dst_entry, 3 ^ 1);
-		if (add) {
+		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		if (is_valid(add)) {
+			add->path = mfi.blob.path = b->path;
 			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
 						  ci->ren1->branch,
 						  ci->ren2->branch,
-						  &add->oid, add->mode,
-						  &mfi.oid, mfi.mode) < 0)
+						  add, &mfi.blob) < 0)
 				return -1;
 		} else {
 			char *new_path = find_path_for_conflict(opt, b->path,
 								ci->ren2->branch,
 								ci->ren1->branch);
-			if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
+			if (update_file(opt, 0, &mfi.blob,
+					new_path ? new_path : b->path))
 				return -1;
 			free(new_path);
 			if (update_stages(opt, b->path, NULL, NULL, b))
@@ -1826,12 +1795,12 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	struct diff_filespec *b = ci->ren2->pair->one;
 	struct diff_filespec *c1 = ci->ren1->pair->two;
 	struct diff_filespec *c2 = ci->ren2->pair->two;
-	struct diff_filespec tmp1, tmp2;
 	char *path = c1->path; /* == c2->path */
 	char *path_side_1_desc;
 	char *path_side_2_desc;
 	struct merge_file_info mfi_c1;
 	struct merge_file_info mfi_c2;
+	int ostage1, ostage2;
 
 	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
@@ -1839,27 +1808,31 @@ static int handle_rename_rename_2to1(struct merge_options *opt,
 	       a->path, c1->path, ci->ren1->branch,
 	       b->path, c2->path, ci->ren2->branch);
 
-	filespec_from_entry(&tmp1, ci->ren1->src_entry, 3);
-	tmp1.path = a->path;
-	filespec_from_entry(&tmp2, ci->ren2->src_entry, 2);
-	tmp2.path = b->path;
-
 	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
 	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	if (merge_mode_and_contents(opt, a, c1, &tmp1, path_side_1_desc,
+	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
+	ostage2 = ostage1 ^ 1;
+	ci->ren1->src_entry->stages[ostage1].path = a->path;
+	ci->ren2->src_entry->stages[ostage2].path = b->path;
+	if (merge_mode_and_contents(opt, a, c1,
+				    &ci->ren1->src_entry->stages[ostage1],
+				    path_side_1_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(opt, b, &tmp2, c2, path_side_2_desc,
+	    merge_mode_and_contents(opt, b,
+				    &ci->ren2->src_entry->stages[ostage2],
+				    c2, path_side_2_desc,
 				    opt->branch1, opt->branch2,
 				    1 + opt->call_depth * 2, &mfi_c2))
 		return -1;
 	free(path_side_1_desc);
 	free(path_side_2_desc);
+	mfi_c1.blob.path = path;
+	mfi_c2.blob.path = path;
 
 	return handle_file_collision(opt, path, a->path, b->path,
 				     ci->ren1->branch, ci->ren2->branch,
-				     &mfi_c1.oid, mfi_c1.mode,
-				     &mfi_c2.oid, mfi_c2.mode);
+				     &mfi_c1.blob, &mfi_c2.blob);
 }
 
 /*
@@ -2722,7 +2695,6 @@ static int process_renames(struct merge_options *opt,
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
 						   opt, ren1, ren2);
-
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
 			/* we only use sha1 and mode of these */
@@ -2771,8 +2743,7 @@ static int process_renames(struct merge_options *opt,
 				 * update_file().
 				 */
 				if (update_file_flags(opt,
-						      &ren1->pair->two->oid,
-						      ren1->pair->two->mode,
+						      ren1->pair->two,
 						      ren1_dst,
 						      1, /* update_cache */
 						      0  /* update_wd    */))
@@ -2923,11 +2894,6 @@ static void final_cleanup_renames(struct rename_info *re_info)
 	final_cleanup_rename(re_info->merge_renames);
 }
 
-static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
-{
-	return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
-}
-
 static int read_oid_strbuf(struct merge_options *opt,
 			   const struct object_id *oid,
 			   struct strbuf *dst)
@@ -2947,10 +2913,8 @@ static int read_oid_strbuf(struct merge_options *opt,
 }
 
 static int blob_unchanged(struct merge_options *opt,
-			  const struct object_id *o_oid,
-			  unsigned o_mode,
-			  const struct object_id *a_oid,
-			  unsigned a_mode,
+			  const struct diff_filespec *o,
+			  const struct diff_filespec *a,
 			  int renormalize, const char *path)
 {
 	struct strbuf obuf = STRBUF_INIT;
@@ -2958,16 +2922,15 @@ static int blob_unchanged(struct merge_options *opt,
 	int ret = 0; /* assume changed for safety */
 	const struct index_state *idx = opt->repo->index;
 
-	if (a_mode != o_mode)
+	if (a->mode != o->mode)
 		return 0;
-	if (oid_eq(o_oid, a_oid))
+	if (oid_eq(&o->oid, &a->oid))
 		return 1;
 	if (!renormalize)
 		return 0;
 
-	assert(o_oid && a_oid);
-	if (read_oid_strbuf(opt, o_oid, &obuf) ||
-	    read_oid_strbuf(opt, a_oid, &abuf))
+	if (read_oid_strbuf(opt, &o->oid, &obuf) ||
+	    read_oid_strbuf(opt, &a->oid, &abuf))
 		goto error_return;
 	/*
 	 * Note: binary | is used so that both renormalizations are
@@ -2986,30 +2949,26 @@ static int blob_unchanged(struct merge_options *opt,
 
 static int handle_modify_delete(struct merge_options *opt,
 				const char *path,
-				struct object_id *o_oid, int o_mode,
-				struct object_id *a_oid, int a_mode,
-				struct object_id *b_oid, int b_mode)
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b)
 {
 	const char *modify_branch, *delete_branch;
-	struct object_id *changed_oid;
-	int changed_mode;
+	const struct diff_filespec *changed;
 
-	if (a_oid) {
+	if (is_valid(a)) {
 		modify_branch = opt->branch1;
 		delete_branch = opt->branch2;
-		changed_oid = a_oid;
-		changed_mode = a_mode;
+		changed = a;
 	} else {
 		modify_branch = opt->branch2;
 		delete_branch = opt->branch1;
-		changed_oid = b_oid;
-		changed_mode = b_mode;
+		changed = b;
 	}
 
 	return handle_change_delete(opt,
 				    path, NULL,
-				    o_oid, o_mode,
-				    changed_oid, changed_mode,
+				    o, changed,
 				    modify_branch, delete_branch,
 				    _("modify"), _("modified"));
 }
@@ -3017,50 +2976,24 @@ static int handle_modify_delete(struct merge_options *opt,
 static int handle_content_merge(struct merge_options *opt,
 				const char *path,
 				int is_dirty,
-				struct object_id *o_oid, int o_mode,
-				struct object_id *a_oid, int a_mode,
-				struct object_id *b_oid, int b_mode,
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b,
 				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
-	const char *path1 = NULL, *path2 = NULL;
 	struct merge_file_info mfi;
-	struct diff_filespec one, a, b;
 	unsigned df_conflict_remains = 0;
 
-	if (!o_oid) {
+	if (!is_valid(o))
 		reason = _("add/add");
-		o_oid = (struct object_id *)&null_oid;
-	}
-	one.path = a.path = b.path = (char *)path;
-	oidcpy(&one.oid, o_oid);
-	one.mode = o_mode;
-	oidcpy(&a.oid, a_oid);
-	a.mode = a_mode;
-	oidcpy(&b.oid, b_oid);
-	b.mode = b_mode;
-
-	if (ci) {
-		struct diff_filepair *pair1 = ci->ren1->pair;
-
-		path1 = (opt->branch1 == ci->ren1->branch) ?
-			pair1->two->path : pair1->one->path;
-		/* If ci->ren2->pair != NULL, we are in
-		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
-		 * normal rename.
-		 */
-		path2 = ((ci->ren2 && ci->ren2->pair) ||
-			 opt->branch2 == ci->ren1->branch) ?
-			pair1->two->path : pair1->one->path;
-		one.path = pair1->one->path;
-		a.path = (char *)path1;
-		b.path = (char *)path2;
-
-		if (dir_in_way(opt->repo->index, path, !opt->call_depth,
-			       S_ISGITLINK(pair1->two->mode)))
-			df_conflict_remains = 1;
-	}
-	if (merge_mode_and_contents(opt, &one, &a, &b, path,
+
+	assert(o->path && a->path && b->path);
+	if (ci && dir_in_way(opt->repo->index, path, !opt->call_depth,
+			     S_ISGITLINK(ci->ren1->pair->two->mode)))
+		df_conflict_remains = 1;
+
+	if (merge_mode_and_contents(opt, o, a, b, path,
 				    opt->branch1, opt->branch2,
 				    opt->call_depth * 2, &mfi))
 		return -1;
@@ -3071,14 +3004,13 @@ static int handle_content_merge(struct merge_options *opt,
 	 *   b) The merge matches what was in HEAD (content, mode, pathname)
 	 *   c) The target path is usable (i.e. not involved in D/F conflict)
 	 */
-	if (mfi.clean &&
-	    was_tracked_and_matches(opt, path, &mfi.oid, mfi.mode) &&
+	if (mfi.clean && was_tracked_and_matches(opt, path, &mfi.blob) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
 		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(opt, mfi.mode, &mfi.oid, path,
+		if (add_cacheinfo(opt, &mfi.blob, path,
 				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
@@ -3098,12 +3030,12 @@ static int handle_content_merge(struct merge_options *opt,
 	}
 
 	if (!mfi.clean) {
-		if (S_ISGITLINK(mfi.mode))
+		if (S_ISGITLINK(mfi.blob.mode))
 			reason = _("submodule");
 		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
 		if (ci && !df_conflict_remains)
-			if (update_stages(opt, path, &one, &a, &b))
+			if (update_stages(opt, path, o, a, b))
 				return -1;
 	}
 
@@ -3113,17 +3045,14 @@ static int handle_content_merge(struct merge_options *opt,
 			remove_file_from_index(opt->repo->index, path);
 		} else {
 			if (!mfi.clean) {
-				if (update_stages(opt, path, &one, &a, &b))
+				if (update_stages(opt, path, o, a, b))
 					return -1;
 			} else {
 				int file_from_stage2 = was_tracked(opt, path);
-				struct diff_filespec merged;
-				oidcpy(&merged.oid, &mfi.oid);
-				merged.mode = mfi.mode;
 
 				if (update_stages(opt, path, NULL,
-						  file_from_stage2 ? &merged : NULL,
-						  file_from_stage2 ? NULL : &merged))
+						  file_from_stage2 ? &mfi.blob : NULL,
+						  file_from_stage2 ? NULL : &mfi.blob))
 					return -1;
 			}
 
@@ -3134,28 +3063,27 @@ static int handle_content_merge(struct merge_options *opt,
 			       path);
 		}
 		output(opt, 1, _("Adding as %s instead"), new_path);
-		if (update_file(opt, 0, &mfi.oid, mfi.mode, new_path)) {
+		if (update_file(opt, 0, &mfi.blob, new_path)) {
 			free(new_path);
 			return -1;
 		}
 		free(new_path);
 		mfi.clean = 0;
-	} else if (update_file(opt, mfi.clean, &mfi.oid, mfi.mode, path))
+	} else if (update_file(opt, mfi.clean, &mfi.blob, path))
 		return -1;
 	return !is_dirty && mfi.clean;
 }
 
 static int handle_rename_normal(struct merge_options *opt,
 				const char *path,
-				struct object_id *o_oid, unsigned int o_mode,
-				struct object_id *a_oid, unsigned int a_mode,
-				struct object_id *b_oid, unsigned int b_mode,
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b,
 				struct rename_conflict_info *ci)
 {
 	/* Merge the content and write it out */
 	return handle_content_merge(opt, path, was_dirty(opt, path),
-				    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
-				    ci);
+				    o, a, b, ci);
 }
 
 /* Per entry merge function */
@@ -3164,24 +3092,36 @@ static int process_entry(struct merge_options *opt,
 {
 	int clean_merge = 1;
 	int normalize = opt->renormalize;
-	unsigned o_mode = entry->stages[1].mode;
-	unsigned a_mode = entry->stages[2].mode;
-	unsigned b_mode = entry->stages[3].mode;
-	struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
-	struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
-	struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
+
+	struct diff_filespec *o = &entry->stages[1];
+	struct diff_filespec *a = &entry->stages[2];
+	struct diff_filespec *b = &entry->stages[3];
+	int o_valid = is_valid(o);
+	int a_valid = is_valid(a);
+	int b_valid = is_valid(b);
+	o->path = a->path = b->path = (char*)path;
 
 	entry->processed = 1;
 	if (entry->rename_conflict_info) {
 		struct rename_conflict_info *ci = entry->rename_conflict_info;
+		struct diff_filespec *temp;
+
+		/*
+		 * For cases with a single rename, {o,a,b}->path have all been
+		 * set to the rename target path; we need to set two of these
+		 * back to the rename source.
+		 * For rename/rename conflicts, we'll manually fix paths below.
+		 */
+		temp = (opt->branch1 == ci->ren1->branch) ? b : a;
+		o->path = temp->path = ci->ren1->pair->one->path;
+		if (ci->ren2) {
+			assert(opt->branch1 == ci->ren1->branch);
+		}
+
 		switch (ci->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
-			clean_merge = handle_rename_normal(opt,
-							   path,
-							   o_oid, o_mode,
-							   a_oid, a_mode,
-							   b_oid, b_mode,
+			clean_merge = handle_rename_normal(opt, path, o, a, b,
 							   ci);
 			break;
 		case RENAME_VIA_DIR:
@@ -3204,11 +3144,27 @@ static int process_entry(struct merge_options *opt,
 				clean_merge = -1;
 			break;
 		case RENAME_ONE_FILE_TO_TWO:
+			/*
+			 * Manually fix up paths; note:
+			 * ren[12]->pair->one->path are equal.
+			 */
+			o->path = ci->ren1->pair->one->path;
+			a->path = ci->ren1->pair->two->path;
+			b->path = ci->ren2->pair->two->path;
+
 			clean_merge = 0;
 			if (handle_rename_rename_1to2(opt, ci))
 				clean_merge = -1;
 			break;
 		case RENAME_TWO_FILES_TO_ONE:
+			/*
+			 * Manually fix up paths; note,
+			 * ren[12]->pair->two->path are actually equal.
+			 */
+			o->path = NULL;
+			a->path = ci->ren1->pair->two->path;
+			b->path = ci->ren2->pair->two->path;
+
 			/*
 			 * Probably unclean merge, but if the two renamed
 			 * files merge cleanly and the two resulting files
@@ -3221,57 +3177,53 @@ static int process_entry(struct merge_options *opt,
 			entry->processed = 0;
 			break;
 		}
-	} else if (o_oid && (!a_oid || !b_oid)) {
+	} else if (o_valid && (!a_valid || !b_valid)) {
 		/* Case A: Deleted in one */
-		if ((!a_oid && !b_oid) ||
-		    (!b_oid && blob_unchanged(opt, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
-		    (!a_oid && blob_unchanged(opt, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
+		if ((!a_valid && !b_valid) ||
+		    (!b_valid && blob_unchanged(opt, o, a, normalize, path)) ||
+		    (!a_valid && blob_unchanged(opt, o, b, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
-			if (a_oid)
+			if (a_valid)
 				output(opt, 2, _("Removing %s"), path);
 			/* do not touch working file if it did not exist */
-			remove_file(opt, 1, path, !a_oid);
+			remove_file(opt, 1, path, !a_valid);
 		} else {
 			/* Modify/delete; deleted side may have put a directory in the way */
 			clean_merge = 0;
-			if (handle_modify_delete(opt, path, o_oid, o_mode,
-						 a_oid, a_mode, b_oid, b_mode))
+			if (handle_modify_delete(opt, path, o, a, b))
 				clean_merge = -1;
 		}
-	} else if ((!o_oid && a_oid && !b_oid) ||
-		   (!o_oid && !a_oid && b_oid)) {
+	} else if ((!o_valid && a_valid && !b_valid) ||
+		   (!o_valid && !a_valid && b_valid)) {
 		/* Case B: Added in one. */
 		/* [nothing|directory] -> ([nothing|directory], file) */
 
 		const char *add_branch;
 		const char *other_branch;
-		unsigned mode;
-		const struct object_id *oid;
 		const char *conf;
+		const struct diff_filespec *contents;
 
-		if (a_oid) {
+		if (a_valid) {
 			add_branch = opt->branch1;
 			other_branch = opt->branch2;
-			mode = a_mode;
-			oid = a_oid;
+			contents = a;
 			conf = _("file/directory");
 		} else {
 			add_branch = opt->branch2;
 			other_branch = opt->branch1;
-			mode = b_mode;
-			oid = b_oid;
+			contents = b;
 			conf = _("directory/file");
 		}
 		if (dir_in_way(opt->repo->index, path,
-			       !opt->call_depth && !S_ISGITLINK(a_mode),
+			       !opt->call_depth && !S_ISGITLINK(a->mode),
 			       0)) {
 			char *new_path = unique_path(opt, path, add_branch);
 			clean_merge = 0;
 			output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
 			       "Adding %s as %s"),
 			       conf, path, other_branch, path, new_path);
-			if (update_file(opt, 0, oid, mode, new_path))
+			if (update_file(opt, 0, contents, new_path))
 				clean_merge = -1;
 			else if (opt->call_depth)
 				remove_file_from_index(opt->repo->index, path);
@@ -3279,11 +3231,11 @@ static int process_entry(struct merge_options *opt,
 		} else {
 			output(opt, 2, _("Adding %s"), path);
 			/* do not overwrite file if already present */
-			if (update_file_flags(opt, oid, mode, path, 1, !a_oid))
+			if (update_file_flags(opt, contents, path, 1, !a_valid))
 				clean_merge = -1;
 		}
-	} else if (a_oid && b_oid) {
-		if (!o_oid) {
+	} else if (a_valid && b_valid) {
+		if (!o_valid) {
 			/* Case C: Added in both (check for same permissions) */
 			output(opt, 1,
 			       _("CONFLICT (add/add): Merge conflict in %s"),
@@ -3292,24 +3244,19 @@ static int process_entry(struct merge_options *opt,
 							    path, NULL, NULL,
 							    opt->branch1,
 							    opt->branch2,
-							    a_oid, a_mode,
-							    b_oid, b_mode);
+							    a, b);
 		} else {
 			/* case D: Modified in both, but differently. */
 			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(opt, path,
-							   is_dirty,
-							   o_oid, o_mode,
-							   a_oid, a_mode,
-							   b_oid, b_mode,
-							   NULL);
+			clean_merge = handle_content_merge(opt, path, is_dirty,
+							   o, a, b, NULL);
 		}
-	} else if (!o_oid && !a_oid && !b_oid) {
+	} else if (!o_valid && !a_valid && !b_valid) {
 		/*
 		 * this entry was deleted altogether. a_mode == 0 means
 		 * we had that path and want to actively remove it.
 		 */
-		remove_file(opt, 1, path, !a_mode);
+		remove_file(opt, 1, path, !a->mode);
 	} else
 		BUG("fatal merge failure, shouldn't happen.");
 
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 12/15] t6043: fix copied test description to match its purpose

[Elijah Newren]

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 t/t6043-merge-rename-directories.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
index 62c564707b..fe205be607 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6043-merge-rename-directories.sh
@@ -3910,7 +3910,7 @@ test_expect_success '12a-check: Moving one directory hierarchy into another' '
 #         To which, I can do no more than shrug my shoulders and say that
 #         even simple rules give weird results when given weird inputs.
 
-test_expect_success '12b-setup: Moving one directory hierarchy into another' '
+test_expect_success '12b-setup: Moving two directory hierarchies into each other' '
 	test_create_repo 12b &&
 	(
 		cd 12b &&
@@ -3940,7 +3940,7 @@ test_expect_success '12b-setup: Moving one directory hierarchy into another' '
 	)
 '
 
-test_expect_success '12b-check: Moving one directory hierarchy into another' '
+test_expect_success '12b-check: Moving two directory hierarchies into each other' '
 	(
 		cd 12b &&
 
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 13/15] merge-recursive: track information associated with directory renames

[Elijah Newren]

Directory rename detection previously silently applied.  In order to
allow printing information about paths that changed or printing a
conflict notification (and only doing so near other potential conflict
messages associated with the paths), save this information inside the
rename struct for later use.  A subsequent patch will make use of the
additional information.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 1d2c9e1772..938a526b20 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -207,8 +207,16 @@ struct stage_data {
 };
 
 struct rename {
+	unsigned processed:1;
 	struct diff_filepair *pair;
 	const char *branch; /* branch that the rename occurred on */
+	/*
+	 * If directory rename detection affected this rename, what was its
+	 * original type ('A' or 'R') and it's original destination before
+	 * the directory rename (otherwise, '\0' and NULL for these two vars).
+	 */
+	char dir_rename_original_type;
+	char *dir_rename_original_dest;
 	/*
 	 * Purpose of src_entry and dst_entry:
 	 *
@@ -230,8 +238,6 @@ struct rename {
 	 */
 	struct stage_data *src_entry;
 	struct stage_data *dst_entry;
-	unsigned add_turned_into_rename:1;
-	unsigned processed:1;
 };
 
 struct rename_conflict_info {
@@ -2484,16 +2490,18 @@ static void apply_directory_rename_modifications(struct merge_options *opt,
 		       &re->dst_entry->stages[stage].oid,
 		       &re->dst_entry->stages[stage].mode);
 
-	/* Update pair status */
-	if (pair->status == 'A') {
-		/*
-		 * Recording rename information for this add makes it look
-		 * like a rename/delete conflict.  Make sure we can
-		 * correctly handle this as an add that was moved to a new
-		 * directory instead of reporting a rename/delete conflict.
-		 */
-		re->add_turned_into_rename = 1;
-	}
+	/*
+	 * Record the original change status (or 'type' of change).  If it
+	 * was originally an add ('A'), this lets us differentiate later
+	 * between a RENAME_DELETE conflict and RENAME_VIA_DIR (they
+	 * otherwise look the same).  If it was originally a rename ('R'),
+	 * this lets us remember and report accurately about the transitive
+	 * renaming that occurred via the directory rename detection.  Also,
+	 * record the original destination name.
+	 */
+	re->dir_rename_original_type = pair->status;
+	re->dir_rename_original_dest = pair->two->path;
+
 	/*
 	 * We don't actually look at pair->status again, but it seems
 	 * pedagogically correct to adjust it.
@@ -2556,9 +2564,10 @@ static struct string_list *get_renames(struct merge_options *opt,
 
 		re = xmalloc(sizeof(*re));
 		re->processed = 0;
-		re->add_turned_into_rename = 0;
 		re->pair = pair;
 		re->branch = branch;
+		re->dir_rename_original_type = '\0';
+		re->dir_rename_original_dest = NULL;
 		item = string_list_lookup(entries, re->pair->one->path);
 		if (!item)
 			re->src_entry = insert_stage_data(re->pair->one->path,
@@ -2726,7 +2735,7 @@ static int process_renames(struct merge_options *opt,
 			try_merge = 0;
 
 			if (oid_eq(&src_other.oid, &null_oid) &&
-			    ren1->add_turned_into_rename) {
+			    ren1->dir_rename_original_type == 'A') {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
 							   opt, ren1, NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 14/15] merge-recursive: give callers of handle_content_merge() access to contents

[Elijah Newren]

Pass a merge_file_info struct to handle_content_merge() so that the
callers can access the oid and mode of the result afterward.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 938a526b20..2edfa01e43 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -2982,7 +2982,8 @@ static int handle_modify_delete(struct merge_options *opt,
 				    _("modify"), _("modified"));
 }
 
-static int handle_content_merge(struct merge_options *opt,
+static int handle_content_merge(struct merge_file_info *mfi,
+				struct merge_options *opt,
 				const char *path,
 				int is_dirty,
 				const struct diff_filespec *o,
@@ -2991,7 +2992,6 @@ static int handle_content_merge(struct merge_options *opt,
 				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
-	struct merge_file_info mfi;
 	unsigned df_conflict_remains = 0;
 
 	if (!is_valid(o))
@@ -3004,7 +3004,7 @@ static int handle_content_merge(struct merge_options *opt,
 
 	if (merge_mode_and_contents(opt, o, a, b, path,
 				    opt->branch1, opt->branch2,
-				    opt->call_depth * 2, &mfi))
+				    opt->call_depth * 2, mfi))
 		return -1;
 
 	/*
@@ -3013,13 +3013,13 @@ static int handle_content_merge(struct merge_options *opt,
 	 *   b) The merge matches what was in HEAD (content, mode, pathname)
 	 *   c) The target path is usable (i.e. not involved in D/F conflict)
 	 */
-	if (mfi.clean && was_tracked_and_matches(opt, path, &mfi.blob) &&
+	if (mfi->clean && was_tracked_and_matches(opt, path, &mfi->blob) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
 		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(opt, &mfi.blob, path,
+		if (add_cacheinfo(opt, &mfi->blob, path,
 				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
@@ -3035,11 +3035,11 @@ static int handle_content_merge(struct merge_options *opt,
 			ce = opt->repo->index->cache[pos];
 			ce->ce_flags |= CE_SKIP_WORKTREE;
 		}
-		return mfi.clean;
+		return mfi->clean;
 	}
 
-	if (!mfi.clean) {
-		if (S_ISGITLINK(mfi.blob.mode))
+	if (!mfi->clean) {
+		if (S_ISGITLINK(mfi->blob.mode))
 			reason = _("submodule");
 		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
@@ -3053,15 +3053,15 @@ static int handle_content_merge(struct merge_options *opt,
 		if (opt->call_depth) {
 			remove_file_from_index(opt->repo->index, path);
 		} else {
-			if (!mfi.clean) {
+			if (!mfi->clean) {
 				if (update_stages(opt, path, o, a, b))
 					return -1;
 			} else {
 				int file_from_stage2 = was_tracked(opt, path);
 
 				if (update_stages(opt, path, NULL,
-						  file_from_stage2 ? &mfi.blob : NULL,
-						  file_from_stage2 ? NULL : &mfi.blob))
+						  file_from_stage2 ? &mfi->blob : NULL,
+						  file_from_stage2 ? NULL : &mfi->blob))
 					return -1;
 			}
 
@@ -3072,15 +3072,15 @@ static int handle_content_merge(struct merge_options *opt,
 			       path);
 		}
 		output(opt, 1, _("Adding as %s instead"), new_path);
-		if (update_file(opt, 0, &mfi.blob, new_path)) {
+		if (update_file(opt, 0, &mfi->blob, new_path)) {
 			free(new_path);
 			return -1;
 		}
 		free(new_path);
-		mfi.clean = 0;
-	} else if (update_file(opt, mfi.clean, &mfi.blob, path))
+		mfi->clean = 0;
+	} else if (update_file(opt, mfi->clean, &mfi->blob, path))
 		return -1;
-	return !is_dirty && mfi.clean;
+	return !is_dirty && mfi->clean;
 }
 
 static int handle_rename_normal(struct merge_options *opt,
@@ -3091,7 +3091,8 @@ static int handle_rename_normal(struct merge_options *opt,
 				struct rename_conflict_info *ci)
 {
 	/* Merge the content and write it out */
-	return handle_content_merge(opt, path, was_dirty(opt, path),
+	struct merge_file_info mfi;
+	return handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
 				    o, a, b, ci);
 }
 
@@ -3256,8 +3257,10 @@ static int process_entry(struct merge_options *opt,
 							    a, b);
 		} else {
 			/* case D: Modified in both, but differently. */
+			struct merge_file_info mfi;
 			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(opt, path, is_dirty,
+			clean_merge = handle_content_merge(&mfi, opt, path,
+							   is_dirty,
 							   o, a, b, NULL);
 		}
 	} else if (!o_valid && !a_valid && !b_valid) {
-- 
2.21.0.211.g719c25afaf.dirty

[PATCH v3 15/15] merge-recursive: switch directory rename detection default

[Elijah Newren]

When all of x/a, x/b, and x/c have moved to z/a, z/b, and z/c on one
branch, there is a question about whether x/d added on a different
branch should remain at x/d or appear at z/d when the two branches are
merged.  There are different possible viewpoints here:

  A) The file was placed at x/d; it's unrelated to the other files in
     x/ so it doesn't matter that all the files from x/ moved to z/ on
     one branch; x/d should still remain at x/d.

  B) x/d is related to the other files in x/, and x/ was renamed to z/;
     therefore x/d should be moved to z/d.

Since there was no ability to detect directory renames prior to
git-2.18, users experienced (A) regardless of context.  Choice (B) was
implemented in git-2.18, with no option to go back to (A), and has been
in use since.  However, one user reported that the merge results did not
match their expectations, making the change of default problematic,
especially since there was no notice printed when directory rename
detection moved files.

Note that there is also a third possibility here:

  C) There are different answers depending on the context and content
     that cannot be determined by git, so this is a conflict.  Use a
     higher stage in the index to record the conflict and notify the
     user of the potential issue instead of silently selecting a
     resolution for them.

Add an option for users to specify their preference for whether to use
directory rename detection, and default to (C).  Even when directory
rename detection is on, add notice messages about files moved into new
directories.

As a sidenote, x/d did not have to be a new file here; it could have
already existed at some other path and been renamed to x/d, with
directory rename detection just renaming it again to z/d.  Thus, it's
not just new files, but also a modification to all rename types (normal
renames, rename/add, rename/delete, rename/rename(1to1),
rename/rename(1to2), and rename/rename(2to1)).

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 Documentation/config/merge.txt         |  19 +-
 merge-recursive.c                      | 146 ++++++--
 t/t3401-rebase-and-am-rename.sh        |   8 +-
 t/t6043-merge-rename-directories.sh    | 458 ++++++++++++++++++++++---
 t/t6046-merge-skip-unneeded-updates.sh |   8 +-
 5 files changed, 552 insertions(+), 87 deletions(-)

diff --git a/Documentation/config/merge.txt b/Documentation/config/merge.txt
index d389c73929..6a313937f8 100644
--- a/Documentation/config/merge.txt
+++ b/Documentation/config/merge.txt
@@ -39,9 +39,22 @@ merge.renameLimit::
 	is turned off.
 
 merge.renames::
-	Whether and how Git detects renames.  If set to "false",
-	rename detection is disabled. If set to "true", basic rename
-	detection is enabled.  Defaults to the value of diff.renames.
+	Whether Git detects renames.  If set to "false", rename detection
+	is disabled. If set to "true", basic rename detection is enabled.
+	Defaults to the value of diff.renames.
+
+merge.directoryRenames::
+	Whether Git detects directory renames, affecting what happens at
+	merge time to new files added to a directory on one side of
+	history when that directory was renamed on the other side of
+	history.  If merge.directoryRenames is set to "false", directory
+	rename detection is disabled, meaning that such new files will be
+	left behind in the old directory.  If set to "true", directory
+	rename detection is enabled, meaning that such new files will be
+	moved into the new directory.  If set to "conflict", a conflict
+	will be reported for such paths.  If merge.renames is false,
+	merge.directoryRenames is ignored and treated as false.  Defaults
+	to "conflict".
 
 merge.renormalize::
 	Tell Git that canonical representation of files in the
diff --git a/merge-recursive.c b/merge-recursive.c
index 2edfa01e43..36af441faa 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1370,30 +1370,39 @@ static int handle_rename_via_dir(struct merge_options *opt,
 	 */
 	const struct rename *ren = ci->ren1;
 	const struct diff_filespec *dest = ren->pair->two;
+	char *file_path = dest->path;
+	int mark_conflicted = (opt->detect_directory_renames == 1);
+	assert(ren->dir_rename_original_dest);
 
 	if (!opt->call_depth && would_lose_untracked(opt, dest->path)) {
-		char *alt_path = unique_path(opt, dest->path, ren->branch);
-
+		mark_conflicted = 1;
+		file_path = unique_path(opt, dest->path, ren->branch);
 		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
-			       "writing to %s instead."),
-		       dest->path, alt_path);
+				 "writing to %s instead."),
+		       dest->path, file_path);
+	}
+
+	if (mark_conflicted) {
 		/*
-		 * Write the file in worktree at alt_path, but not in the
-		 * index.  Instead, write to dest->path for the index but
-		 * only at the higher appropriate stage.
+		 * Write the file in worktree at file_path.  In the index,
+		 * only record the file at dest->path in the appropriate
+		 * higher stage.
 		 */
-		if (update_file(opt, 0, dest, alt_path))
+		if (update_file(opt, 0, dest, file_path))
 			return -1;
-		free(alt_path);
-		return update_stages(opt, dest->path, NULL,
-				     ren->branch == opt->branch1 ? dest : NULL,
-				     ren->branch == opt->branch1 ? NULL : dest);
+		if (file_path != dest->path)
+			free(file_path);
+		if (update_stages(opt, dest->path, NULL,
+				  ren->branch == opt->branch1 ? dest : NULL,
+				  ren->branch == opt->branch1 ? NULL : dest))
+			return -1;
+		return 0; /* not clean, but conflicted */
+	} else {
+		/* Update dest->path both in index and in worktree */
+		if (update_file(opt, 1, dest, dest->path))
+			return -1;
+		return 1; /* clean */
 	}
-
-	/* Update dest->path both in index and in worktree */
-	if (update_file(opt, 1, dest, dest->path))
-		return -1;
-	return 0;
 }
 
 static int handle_change_delete(struct merge_options *opt,
@@ -3090,10 +3099,88 @@ static int handle_rename_normal(struct merge_options *opt,
 				const struct diff_filespec *b,
 				struct rename_conflict_info *ci)
 {
-	/* Merge the content and write it out */
+	struct rename *ren = ci->ren1;
 	struct merge_file_info mfi;
-	return handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
-				    o, a, b, ci);
+	int clean;
+	int side = (ren->branch == opt->branch1 ? 2 : 3);
+
+	/* Merge the content and write it out */
+	clean = handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
+				     o, a, b, ci);
+
+	if (clean && opt->detect_directory_renames == 1 &&
+	    ren->dir_rename_original_dest) {
+		if (update_stages(opt, path,
+				  NULL,
+				  side == 2 ? &mfi.blob : NULL,
+				  side == 2 ? NULL : &mfi.blob))
+			return -1;
+		clean = 0; /* not clean, but conflicted */
+	}
+	return clean;
+}
+
+static void dir_rename_warning(const char *msg,
+			       int is_add,
+			       int clean,
+			       struct merge_options *opt,
+			       struct rename *ren)
+{
+	const char *other_branch;
+	other_branch = (ren->branch == opt->branch1 ?
+			opt->branch2 : opt->branch1);
+	if (is_add) {
+		output(opt, clean ? 2 : 1, msg,
+		       ren->pair->one->path, ren->branch,
+		       other_branch, ren->pair->two->path);
+		return;
+	}
+	output(opt, clean ? 2 : 1, msg,
+	       ren->pair->one->path, ren->dir_rename_original_dest, ren->branch,
+	       other_branch, ren->pair->two->path);
+}
+static int warn_about_dir_renamed_entries(struct merge_options *opt,
+					  struct rename *ren)
+{
+	const char *msg;
+	int clean = 1, is_add;
+
+	if (!ren)
+		return clean;
+
+	/* Return early if ren was not affected/created by a directory rename */
+	if (!ren->dir_rename_original_dest)
+		return clean;
+
+	/* Sanity checks */
+	assert(opt->detect_directory_renames > 0);
+	assert(ren->dir_rename_original_type == 'A' ||
+	       ren->dir_rename_original_type == 'R');
+
+	/* Check whether to treat directory renames as a conflict */
+	clean = (opt->detect_directory_renames == 2);
+
+	is_add = (ren->dir_rename_original_type == 'A');
+	if (ren->dir_rename_original_type == 'A' && clean) {
+		msg = _("Path updated: %s added in %s inside a "
+			"directory that was renamed in %s; moving it to %s.");
+	} else if (ren->dir_rename_original_type == 'A' && !clean) {
+		msg = _("CONFLICT (file location): %s added in %s "
+			"inside a directory that was renamed in %s, "
+			"suggesting it should perhaps be moved to %s.");
+	} else if (ren->dir_rename_original_type == 'R' && clean) {
+		msg = _("Path updated: %s renamed to %s in %s, inside a "
+			"directory that was renamed in %s; moving it to %s.");
+	} else if (ren->dir_rename_original_type == 'R' && !clean) {
+		msg = _("CONFLICT (file location): %s renamed to %s in %s, "
+			"inside a directory that was renamed in %s, "
+			"suggesting it should perhaps be moved to %s.");
+	} else {
+		BUG("Impossible dir_rename_original_type/clean combination");
+	}
+	dir_rename_warning(msg, is_add, clean, opt, ren);
+
+	return clean;
 }
 
 /* Per entry merge function */
@@ -3115,6 +3202,10 @@ static int process_entry(struct merge_options *opt,
 	if (entry->rename_conflict_info) {
 		struct rename_conflict_info *ci = entry->rename_conflict_info;
 		struct diff_filespec *temp;
+		int path_clean;
+
+		path_clean = warn_about_dir_renamed_entries(opt, ci->ren1);
+		path_clean &= warn_about_dir_renamed_entries(opt, ci->ren2);
 
 		/*
 		 * For cases with a single rename, {o,a,b}->path have all been
@@ -3135,9 +3226,7 @@ static int process_entry(struct merge_options *opt,
 							   ci);
 			break;
 		case RENAME_VIA_DIR:
-			clean_merge = 1;
-			if (handle_rename_via_dir(opt, ci))
-				clean_merge = -1;
+			clean_merge = handle_rename_via_dir(opt, ci);
 			break;
 		case RENAME_ADD:
 			/*
@@ -3187,6 +3276,8 @@ static int process_entry(struct merge_options *opt,
 			entry->processed = 0;
 			break;
 		}
+		if (path_clean < clean_merge)
+			clean_merge = path_clean;
 	} else if (o_valid && (!a_valid || !b_valid)) {
 		/* Case A: Deleted in one */
 		if ((!a_valid && !b_valid) ||
@@ -3558,6 +3649,15 @@ static void merge_recursive_config(struct merge_options *opt)
 		opt->merge_detect_rename = git_config_rename("merge.renames", value);
 		free(value);
 	}
+	if (!git_config_get_string("merge.directoryrenames", &value)) {
+		int boolval = git_parse_maybe_bool(value);
+		if (0 <= boolval) {
+			opt->detect_directory_renames = boolval ? 2 : 0;
+		} else if (!strcasecmp(value, "conflict")) {
+			opt->detect_directory_renames = 1;
+		} /* avoid erroring on values from future versions of git */
+		free(value);
+	}
 	git_config(git_xmerge_config, NULL);
 }
 
diff --git a/t/t3401-rebase-and-am-rename.sh b/t/t3401-rebase-and-am-rename.sh
index e0b5111993..a0b9438b22 100755
--- a/t/t3401-rebase-and-am-rename.sh
+++ b/t/t3401-rebase-and-am-rename.sh
@@ -42,7 +42,7 @@ test_expect_success 'rebase --interactive: directory rename detected' '
 		git checkout B^0 &&
 
 		set_fake_editor &&
-		FAKE_LINES="1" git rebase --interactive A &&
+		FAKE_LINES="1" git -c merge.directoryRenames=true rebase --interactive A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -58,7 +58,7 @@ test_expect_failure 'rebase (am): directory rename detected' '
 
 		git checkout B^0 &&
 
-		git rebase A &&
+		git -c merge.directoryRenames=true rebase A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -74,7 +74,7 @@ test_expect_success 'rebase --merge: directory rename detected' '
 
 		git checkout B^0 &&
 
-		git rebase --merge A &&
+		git -c merge.directoryRenames=true rebase --merge A &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -92,7 +92,7 @@ test_expect_failure 'am: directory rename detected' '
 
 		git format-patch -1 B &&
 
-		git am --3way 0001*.patch &&
+		git -c merge.directoryRenames=true am --3way 0001*.patch &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
index fe205be607..50b7543483 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6043-merge-rename-directories.sh
@@ -75,7 +75,7 @@ test_expect_success '1a-check: Simple directory rename detection' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -142,7 +142,7 @@ test_expect_success '1b-check: Merge a directory with another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -201,7 +201,7 @@ test_expect_success '1c-check: Transitive renaming' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -270,7 +270,7 @@ test_expect_success '1d-check: Directory renames cause a rename/rename(2to1) con
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 
 		git ls-files -s >out &&
@@ -350,7 +350,7 @@ test_expect_success '1e-check: Renamed directory, with all files being renamed t
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -416,7 +416,7 @@ test_expect_success '1f-check: Split a directory into two other directories' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -497,7 +497,7 @@ test_expect_success '2a-check: Directory split into two on one side, with equal
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT.*directory rename split" out &&
 
 		git ls-files -s >out &&
@@ -559,7 +559,7 @@ test_expect_success '2b-check: Directory split into two on one side, with equal
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -640,7 +640,7 @@ test_expect_success '3a-check: Avoid implicit rename if involved as source on ot
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -705,7 +705,7 @@ test_expect_success '3b-check: Avoid implicit rename if involved as source on cu
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/d.*x/d.*w/d out &&
 		test_i18ngrep ! CONFLICT.*rename/rename.*y/d out &&
 
@@ -826,7 +826,7 @@ test_expect_success '4a-check: Directory split, with original directory still pr
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 5 out &&
@@ -915,7 +915,7 @@ test_expect_success '5a-check: Merge directories, other side adds files to origi
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT.*implicit dir rename" out &&
 
 		git ls-files -s >out &&
@@ -989,7 +989,7 @@ test_expect_success '5b-check: Rename/delete in order to get add/add/add conflic
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
 
 		git ls-files -s >out &&
@@ -1069,7 +1069,7 @@ test_expect_success '5c-check: Transitive rename would cause rename/rename/renam
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*z/d" out &&
 		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
 
@@ -1153,7 +1153,7 @@ test_expect_success '5d-check: Directory/file/file conflict due to directory ren
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (file/directory).*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1243,7 +1243,7 @@ test_expect_success '6a-check: Tricky rename/delete' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*z/c.*y/c" out &&
 
 		git ls-files -s >out &&
@@ -1308,7 +1308,7 @@ test_expect_success '6b-check: Same rename done on both sides' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1370,7 +1370,7 @@ test_expect_success '6c-check: Rename only done on same side' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1432,7 +1432,7 @@ test_expect_success '6d-check: We do not always want transitive renaming' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -1495,7 +1495,7 @@ test_expect_success '6e-check: Add/add from one side' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -1591,7 +1591,7 @@ test_expect_success '7a-check: rename-dir vs. rename-dir (NOT split evenly) PLUS
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*z/b.*y/b.*w/b" out &&
 		test_i18ngrep "CONFLICT (rename/rename).*z/c.*y/c.*x/c" out &&
 
@@ -1663,7 +1663,7 @@ test_expect_success '7b-check: rename/rename(2to1), but only due to transitive r
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 
 		git ls-files -s >out &&
@@ -1740,7 +1740,7 @@ test_expect_success '7c-check: rename/rename(1to...2or3); transitive rename may
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1804,7 +1804,7 @@ test_expect_success '7d-check: transitive rename involved in rename/delete; how
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1894,7 +1894,7 @@ test_expect_success '7e-check: transitive rename in rename/delete AND dirs in th
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
 
 		git ls-files -s >out &&
@@ -1985,7 +1985,7 @@ test_expect_success '8a-check: Dual-directory rename, one into the others way' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -2063,7 +2063,7 @@ test_expect_success '8b-check: Dual-directory rename, one into the others way, w
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -2135,7 +2135,7 @@ test_expect_success '8c-check: modify/delete or rename+modify/delete' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "CONFLICT (modify/delete).* z/d" out &&
 
 		git ls-files -s >out &&
@@ -2212,7 +2212,7 @@ test_expect_success '8d-check: rename/delete...or not?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2287,7 +2287,7 @@ test_expect_success '8e-check: Both sides rename, one side adds to original dire
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/c.*y/c.*w/c out &&
 		test_i18ngrep CONFLICT.*rename/rename.*z/b.*y/b.*w/b out &&
 
@@ -2374,7 +2374,7 @@ test_expect_success '9a-check: Inner renamed directory within outer renamed dire
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 7 out &&
@@ -2444,7 +2444,7 @@ test_expect_success '9b-check: Transitive rename with content merge' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2534,7 +2534,7 @@ test_expect_success '9c-check: Doubly transitive rename?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "WARNING: Avoiding applying x -> z rename to x/f" out &&
 
 		git ls-files -s >out &&
@@ -2622,7 +2622,7 @@ test_expect_success '9d-check: N-way transitive rename?' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 >out &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		test_i18ngrep "WARNING: Avoiding applying z -> y rename to z/t" out &&
 		test_i18ngrep "WARNING: Avoiding applying y -> x rename to y/a" out &&
 		test_i18ngrep "WARNING: Avoiding applying x -> w rename to x/b" out &&
@@ -2704,7 +2704,7 @@ test_expect_success C_LOCALE_OUTPUT '9e-check: N-to-1 whammo' '
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 >out &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
 		grep "CONFLICT (implicit dir rename): Cannot map more than one path to combined/yo" out >error_line &&
 		grep -q dir1/yo error_line &&
 		grep -q dir2/yo error_line &&
@@ -2782,7 +2782,7 @@ test_expect_success '9f-check: Renamed directory that only contained immediate s
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2849,7 +2849,7 @@ test_expect_failure '9g-check: Renamed directory that only contained immediate s
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2918,7 +2918,7 @@ test_expect_success '9h-check: Avoid dir rename on merely modified path' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 3 out &&
@@ -2993,7 +2993,7 @@ test_expect_success '10a-check: Overwrite untracked with normal rename/delete' '
 		echo very >z/c &&
 		echo important >z/d &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "The following untracked working tree files would be overwritten by merge" err &&
 
 		git ls-files -s >out &&
@@ -3061,7 +3061,7 @@ test_expect_success '10b-check: Overwrite untracked with dir rename + delete' '
 		echo important >y/d &&
 		echo contents >y/e &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/delete).*Version B\^0 of y/d left in tree at y/d~B\^0" out &&
 		test_i18ngrep "Error: Refusing to lose untracked file at y/e; writing to y/e~B\^0 instead" out &&
 
@@ -3137,7 +3137,7 @@ test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)
 		git checkout A^0 &&
 		echo important >y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~B\^0 instead" out &&
 
@@ -3174,7 +3174,7 @@ test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)
 		mkdir y &&
 		echo important >y/c &&
 
-		test_must_fail git merge -s recursive A^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~HEAD instead" out &&
 
@@ -3249,7 +3249,7 @@ test_expect_success '10d-check: Delete untracked with dir rename/rename(2to1)' '
 		git checkout A^0 &&
 		echo important >y/wham &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose untracked file at y/wham" out &&
 
@@ -3327,7 +3327,7 @@ test_expect_failure '10e-check: Does git complain about untracked file that is n
 		mkdir z &&
 		echo random >z/c &&
 
-		git merge -s recursive B^0 >out 2>err &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep ! "following untracked working tree files would be overwritten by merge" err &&
 
 		git ls-files -s >out &&
@@ -3407,7 +3407,7 @@ test_expect_success '11a-check: Avoid losing dirty contents with simple rename'
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		test_seq 1 10 >expected &&
@@ -3479,7 +3479,7 @@ test_expect_success '11b-check: Avoid losing dirty file involved in directory re
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		git merge -s recursive B^0 >out 2>err &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		grep -q stuff z/c &&
@@ -3554,7 +3554,7 @@ test_expect_success '11c-check: Avoid losing not-uptodate with rename + D/F conf
 		git checkout A^0 &&
 		echo stuff >>y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "following files would be overwritten by merge" err &&
 
 		grep -q stuff y/c &&
@@ -3621,7 +3621,7 @@ test_expect_success '11d-check: Avoid losing not-uptodate with rename + D/F conf
 		git checkout A^0 &&
 		echo stuff >>z/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
 
 		grep -q stuff z/c &&
@@ -3700,7 +3700,7 @@ test_expect_success '11e-check: Avoid deleting not-uptodate with dir rename/rena
 		git checkout A^0 &&
 		echo mods >>y/c &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose dirty file at y/c" out &&
 
@@ -3782,7 +3782,7 @@ test_expect_success '11f-check: Avoid deleting not-uptodate with dir rename/rena
 		git checkout A^0 &&
 		echo important >>y/wham &&
 
-		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 		test_i18ngrep "CONFLICT (rename/rename)" out &&
 		test_i18ngrep "Refusing to lose dirty file at y/wham" out &&
 
@@ -3870,7 +3870,7 @@ test_expect_success '12a-check: Moving one directory hierarchy into another' '
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 6 out &&
@@ -3946,7 +3946,7 @@ test_expect_success '12b-check: Moving two directory hierarchies into each other
 
 		git checkout A^0 &&
 
-		git merge -s recursive B^0 &&
+		git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -4016,7 +4016,7 @@ test_expect_success '12c-check: Moving one directory hierarchy into another w/ c
 
 		git checkout A^0 &&
 
-		test_must_fail git merge -s recursive B^0 &&
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 &&
 
 		git ls-files -u >out &&
 		test_line_count = 12 out &&
@@ -4051,4 +4051,356 @@ test_expect_success '12c-check: Moving one directory hierarchy into another w/ c
 	)
 '
 
+###########################################################################
+# SECTION 13: Checking informational and conflict messages
+#
+# A year after directory rename detection became the default, it was
+# instead decided to report conflicts on the pathname on the basis that
+# some users may expect the new files added or moved into a directory to
+# be unrelated to all the other files in that directory, and thus that
+# directory rename detection is unexpected.  Test that the messages printed
+# match our expectation.
+###########################################################################
+
+# Testcase 13a, Basic directory rename with newly added files
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d,e/f}
+#   Expected: y/{b,c,d,e/f}, with notices/conflicts for both y/d and y/e/f
+
+test_expect_success '13a-setup: messages for newly added files' '
+	test_create_repo 13a &&
+	(
+		cd 13a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo d >z/d &&
+		mkdir z/e &&
+		echo f >z/e/f &&
+		git add z/d z/e/f &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13a-check(conflict): messages for newly added files' '
+	(
+		cd 13a &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT..file.location.*z/e/f.added.in.B^0.*y/e/f out &&
+		test_i18ngrep CONFLICT..file.location.*z/d.added.in.B^0.*y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/[de]" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d &&
+		test_path_is_missing z/e/f &&
+		test_path_is_file    y/e/f
+	)
+'
+
+test_expect_success '13a-check(info): messages for newly added files' '
+	(
+		cd 13a &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep Path.updated:.*z/e/f.added.in.B^0.*y/e/f out &&
+		test_i18ngrep Path.updated:.*z/d.added.in.B^0.*y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/[de]" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d &&
+		test_path_is_missing z/e/f &&
+		test_path_is_file    y/e/f
+	)
+'
+
+# Testcase 13b, Transitive rename with conflicted content merge and default
+#               "conflict" setting
+#   (Related to testcase 1c, 9b)
+#   Commit O: z/{b,c},   x/d_1
+#   Commit A: y/{b,c},   x/d_2
+#   Commit B: z/{b,c,d_3}
+#   Expected: y/{b,c,d_merged}, with two conflict messages for y/d,
+#             one about content, and one about file location
+
+test_expect_success '13b-setup: messages for transitive rename with conflicted content' '
+	test_create_repo 13b &&
+	(
+		cd 13b &&
+
+		mkdir x &&
+		mkdir z &&
+		test_seq 1 10 >x/d &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add x z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		echo 11 >>x/d &&
+		git add x/d &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo eleven >>x/d &&
+		git mv x/d z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13b-check(conflict): messages for transitive rename with conflicted content' '
+	(
+		cd 13b &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT.*content.*Merge.conflict.in.y/d out &&
+		test_i18ngrep CONFLICT..file.location.*x/d.renamed.to.z/d.*moved.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+test_expect_success '13b-check(info): messages for transitive rename with conflicted content' '
+	(
+		cd 13b &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT.*content.*Merge.conflict.in.y/d out &&
+		test_i18ngrep Path.updated:.*x/d.renamed.to.z/d.in.B^0.*moving.it.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+# Testcase 13c, Rename/rename(1to1) due to directory rename
+#   Commit O: z/{b,c},   x/{d,e}
+#   Commit A: y/{b,c,d}, x/e
+#   Commit B: z/{b,c,d}, x/e
+#   Expected: y/{b,c,d}, with info or conflict messages for d (
+#             A: renamed x/d -> z/d; B: renamed z/ -> y/ AND renamed x/d to y/d
+#             One could argue A had partial knowledge of what was done with
+#             d and B had full knowledge, but that's a slippery slope as
+#             shown in testcase 13d.
+
+test_expect_success '13c-setup: messages for rename/rename(1to1) via transitive rename' '
+	test_create_repo 13c &&
+	(
+		cd 13c &&
+
+		mkdir x &&
+		mkdir z &&
+		test_seq 1 10 >x/d &&
+		echo e >x/e &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add x z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git mv x/d y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13c-check(conflict): messages for rename/rename(1to1) via transitive rename' '
+	(
+		cd 13c &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT..file.location.*x/d.renamed.to.z/d.*moved.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+test_expect_success '13c-check(info): messages for rename/rename(1to1) via transitive rename' '
+	(
+		cd 13c &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep Path.updated:.*x/d.renamed.to.z/d.in.B^0.*moving.it.to.y/d out &&
+
+		git ls-files >paths &&
+		! grep z/ paths &&
+		grep "y/d" paths &&
+
+		test_path_is_missing z/d &&
+		test_path_is_file    y/d
+	)
+'
+
+# Testcase 13d, Rename/rename(1to1) due to directory rename on both sides
+#   Commit O: a/{z,y}, b/x,     c/w
+#   Commit A: a/z,     b/{y,x}, d/w
+#   Commit B: a/z,     d/x,     c/{y,w}
+#   Expected: a/z, d/{y,x,w} with no file location conflict for x
+#             Easy cases:
+#               * z is always in a; so it stays in a.
+#               * x starts in b, only modified on one side to move into d/
+#               * w starts in c, only modified on one side to move into d/
+#             Hard case:
+#               * A renames a/y to b/y, and B renames b/->d/ => a/y -> d/y
+#               * B renames a/y to c/y, and A renames c/->d/ => a/y -> d/y
+#               No conflict in where a/y ends up, so put it in d/y.
+
+test_expect_success '13d-setup: messages for rename/rename(1to1) via dual transitive rename' '
+	test_create_repo 13d &&
+	(
+		cd 13d &&
+
+		mkdir a &&
+		mkdir b &&
+		mkdir c &&
+		echo z >a/z &&
+		echo y >a/y &&
+		echo x >b/x &&
+		echo w >c/w &&
+		git add a b c &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv a/y b/ &&
+		git mv c/ d/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv a/y c/ &&
+		git mv b/ d/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '13d-check(conflict): messages for rename/rename(1to1) via dual transitive rename' '
+	(
+		cd 13d &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep CONFLICT..file.location.*a/y.renamed.to.b/y.*moved.to.d/y out &&
+		test_i18ngrep CONFLICT..file.location.*a/y.renamed.to.c/y.*moved.to.d/y out &&
+
+		git ls-files >paths &&
+		! grep b/ paths &&
+		! grep c/ paths &&
+		grep "d/y" paths &&
+
+		test_path_is_missing b/y &&
+		test_path_is_missing c/y &&
+		test_path_is_file    d/y
+	)
+'
+
+test_expect_success '13d-check(info): messages for rename/rename(1to1) via dual transitive rename' '
+	(
+		cd 13d &&
+
+		git reset --hard &&
+		git checkout A^0 &&
+
+		git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep Path.updated.*a/y.renamed.to.b/y.*moving.it.to.d/y out &&
+		test_i18ngrep Path.updated.*a/y.renamed.to.c/y.*moving.it.to.d/y out &&
+
+		git ls-files >paths &&
+		! grep b/ paths &&
+		! grep c/ paths &&
+		grep "d/y" paths &&
+
+		test_path_is_missing b/y &&
+		test_path_is_missing c/y &&
+		test_path_is_file    d/y
+	)
+'
+
 test_done
diff --git a/t/t6046-merge-skip-unneeded-updates.sh b/t/t6046-merge-skip-unneeded-updates.sh
index 38e24f787c..3a47623ed3 100755
--- a/t/t6046-merge-skip-unneeded-updates.sh
+++ b/t/t6046-merge-skip-unneeded-updates.sh
@@ -466,7 +466,7 @@ test_expect_success '3a-check-L: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout A^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
@@ -495,7 +495,7 @@ test_expect_success '3a-check-R: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout B^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
@@ -560,7 +560,7 @@ test_expect_success '3b-check-L: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout A^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive B^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
@@ -589,7 +589,7 @@ test_expect_success '3b-check-R: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
 
 		git checkout B^0 &&
 
-		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+		GIT_MERGE_VERBOSITY=3 git -c merge.directoryRenames=true merge -s recursive A^0 >out 2>err &&
 
 		test_i18ngrep ! "Skipped bar/bq" out &&
 		test_must_be_empty err &&
-- 
2.21.0.211.g719c25afaf.dirty

Re: [PATCH v3 00/15] Switch directory rename detection default

[Jacob Keller]

On Fri, Apr 5, 2019 at 8:03 AM Elijah Newren <newren@gmail.com> wrote:
>
> This series adds a new configuration option, merge.directoryRenames,
> for setting how to make use of directory rename detection heuristics.
> The default becomes "conflict", meaning that conflicts are reported
> instead of silently moving paths according to the heuristics.  Also,
> even when merge.directoryRenames config setting is "true", this series
> changes behavior in that it now prints informational messages about
> paths that are adjusted by the directory rename detection heuristics.
>

I read through the v2 series, and the range diff on v3. I thought it
looked good.

> Changes since v2 (range-diff below):
>   * Made use of git_parse_maybe_bool() as suggested by Ævar, and made
>     the parsing of the merge.directoryRenames setting look more like
>     that for merge.ff.
>
> I didn't get much review of round 2, which maybe means everyone is
> happy with what they see.  If anyone would like to take a look at just
> part of the series, the pieces I'd most like folks to look at are:
>   * Patch 15, particularly looking over the new testcases (13a-13d) in
>     t6043 and the documentation.

The documentation made sense to me. I can't speak much towards the
implementation, but I definitely agree that conflicting is a suitable
default, and better than silently renaming.

>   * Should I have switched the type of "mode" from 'unsigned short' to
>     'unsigned' instead of vice-versa in patch 1?

I think switching to unsigned short is better. Unless we need the full
integer width for some reason? but since it's already short I don't
see why we would..

>   * Similarly, does anyone have a reason to prefer oid,mode pair over
>     using a diff_filespec (in patch 11 I convert half the sites to the
>     latter)?
>


>
> Elijah Newren (15):
>   Use 'unsigned short' for mode, like diff_filespec does
>   merge-recursive: rename merge_options argument from 'o' to 'opt'
>   merge-recursive: rename diff_filespec 'one' to 'o'
>   merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
>   merge-recursive: use 'ci' for rename_conflict_info variable name
>   merge-recursive: move some struct declarations together
>   merge-recursive: shrink rename_conflict_info
>   merge-recursive: remove ren[12]_other fields from rename_conflict_info
>   merge-recursive: track branch where rename occurred in rename struct
>   merge-recursive: cleanup handle_rename_* function signatures
>   merge-recursive: switch from (oid,mode) pairs to a diff_filespec
>   t6043: fix copied test description to match its purpose
>   merge-recursive: track information associated with directory renames
>   merge-recursive: give callers of handle_content_merge() access to
>     contents
>   merge-recursive: switch directory rename detection default
>
>  Documentation/config/merge.txt         |   19 +-
>  archive.c                              |    2 +-
>  blame.c                                |    2 +-
>  blame.h                                |    2 +-
>  builtin/rm.c                           |    2 +-
>  builtin/update-index.c                 |    2 +-
>  cache.h                                |    2 +-
>  fsck.c                                 |    2 +-
>  line-log.c                             |    2 +-
>  match-trees.c                          |    8 +-
>  merge-recursive.c                      | 1853 ++++++++++++------------
>  notes.c                                |    2 +-
>  sha1-name.c                            |    2 +-
>  t/t3401-rebase-and-am-rename.sh        |    8 +-
>  t/t6043-merge-rename-directories.sh    |  462 +++++-
>  t/t6046-merge-skip-unneeded-updates.sh |    8 +-
>  tree-diff.c                            |    2 +-
>  tree-walk.c                            |    6 +-
>  tree-walk.h                            |    6 +-
>  19 files changed, 1367 insertions(+), 1025 deletions(-)
>
> Range-diff:
>  1:  bb5b410a61 =  1:  bb5b410a61 Use 'unsigned short' for mode, like diff_filespec does
>  2:  f91c28257e =  2:  f91c28257e merge-recursive: rename merge_options argument from 'o' to 'opt'
>  3:  e3fe8baa15 =  3:  e3fe8baa15 merge-recursive: rename diff_filespec 'one' to 'o'
>  4:  c6bd963ffb =  4:  c6bd963ffb merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
>  5:  eca30e7571 =  5:  eca30e7571 merge-recursive: use 'ci' for rename_conflict_info variable name
>  6:  07f0d5fa8e =  6:  07f0d5fa8e merge-recursive: move some struct declarations together
>  7:  4cdd1ecbcb =  7:  4cdd1ecbcb merge-recursive: shrink rename_conflict_info
>  8:  3490324bdd =  8:  3490324bdd merge-recursive: remove ren[12]_other fields from rename_conflict_info
>  9:  fb73a2c55d =  9:  fb73a2c55d merge-recursive: track branch where rename occurred in rename struct
> 10:  124ee08ed8 = 10:  124ee08ed8 merge-recursive: cleanup handle_rename_* function signatures
> 11:  78a5916efe = 11:  78a5916efe merge-recursive: switch from (oid,mode) pairs to a diff_filespec
> 12:  a8309326c1 = 12:  a8309326c1 t6043: fix copied test description to match its purpose
> 13:  b362f4db1e = 13:  b362f4db1e merge-recursive: track information associated with directory renames
> 14:  2e0258a358 = 14:  2e0258a358 merge-recursive: give callers of handle_content_merge() access to contents
> 15:  719c25afaf ! 15:  428cdf62b3 merge-recursive: switch directory rename detection default
>     @@ -262,17 +262,12 @@
>                 free(value);
>         }
>      +  if (!git_config_get_string("merge.directoryrenames", &value)) {
>     -+          if (!strcasecmp(value, "true"))
>     -+                  opt->detect_directory_renames = 2;
>     -+          else if (!strcasecmp(value, "false"))
>     -+                  opt->detect_directory_renames = 0;
>     -+          else if (!strcasecmp(value, "conflict"))
>     ++          int boolval = git_parse_maybe_bool(value);
>     ++          if (0 <= boolval) {
>     ++                  opt->detect_directory_renames = boolval ? 2 : 0;
>     ++          } else if (!strcasecmp(value, "conflict")) {
>      +                  opt->detect_directory_renames = 1;
>     -+          else {
>     -+                  error(_("Invalid value for merge.directoryRenames: %s"),
>     -+                        value);
>     -+                  opt->detect_directory_renames = 1;
>     -+          }
>     ++          } /* avoid erroring on values from future versions of git */
>      +          free(value);
>      +  }
>         git_config(git_xmerge_config, NULL);
> --
> 2.21.0.211.g719c25afaf.dirty
>