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From: Stefan Beller <sbeller@google.com>
To: Elijah Newren <newren@gmail.com>
Cc: git <git@vger.kernel.org>
Subject: Re: [PATCH 03/30] merge-recursive: Add explanation for src_entry and dst_entry
Date: Mon, 13 Nov 2017 13:06:37 -0800	[thread overview]
Message-ID: <CAGZ79kZ7d7fMp3Cw3Yy4bq9-Mh5Z_jhM5XDQbkVLoqzm6ONzDg@mail.gmail.com> (raw)
In-Reply-To: <20171110190550.27059-4-newren@gmail.com>

On Fri, Nov 10, 2017 at 11:05 AM, Elijah Newren <newren@gmail.com> wrote:
> If I have to walk through the debugger and inspect the values found in
> here in order to figure out their meaning, despite having known these
> things inside and out some years back, then they probably need a comment
> for the casual reader to explain their purpose.
>
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
>  merge-recursive.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/merge-recursive.c b/merge-recursive.c
> index 52521faf09..3526c8d0b8 100644
> --- a/merge-recursive.c
> +++ b/merge-recursive.c
> @@ -513,6 +513,28 @@ static void record_df_conflict_files(struct merge_options *o,
>
>  struct rename {
>         struct diff_filepair *pair;
> +       /*
> +        * Because I keep forgetting every few years what src_entry and
> +        * dst_entry are and have to walk through a debugger and puzzle
> +        * through it to remind myself...

This repeats the commit message; and doesn't help me understanding the
{src/dst}_entry. (Maybe drop the first part here?) I'll read on.

> +        *
> +        * 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 versions of
> +        * 'after' from the merge_base, HEAD, and MERGE in stages 1, 2, and
> +        * 3.

So src == before, dst = after; no trickery with the stages (the same
stage number
before and after; only the order needs to be conveyed:
base, HEAD (ours?), MERGE (theirs?)

I can understand that, so I wonder if we can phrase it to mention (base,
HEAD, MERGE) just once.

>     Thus, we have a total of six modes and oids, though some
> +        * will be null.  (Stage 0 is ignored; we're interested in handling

s/will be/may be/ or /can be/?

> +        * 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.

Oh. That explains the choice of /will be/ above. Thanks!

> +        * 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.

That makes sense.

Thanks,
Stefan

> +        */
>         struct stage_data *src_entry;
>         struct stage_data *dst_entry;
>         unsigned processed:1;
> --
> 2.15.0.5.g9567be9905
>

  reply	other threads:[~2017-11-13 21:06 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-10 19:05 [PATCH 00/30] Add directory rename detection to git Elijah Newren
2017-11-10 19:05 ` [PATCH 01/30] Tighten and correct a few testcases for merging and cherry-picking Elijah Newren
2017-11-13 19:32   ` Stefan Beller
2017-11-10 19:05 ` [PATCH 02/30] merge-recursive: Fix logic ordering issue Elijah Newren
2017-11-13 19:48   ` Stefan Beller
2017-11-13 22:04     ` Elijah Newren
2017-11-13 22:12       ` Stefan Beller
2017-11-13 23:39         ` Elijah Newren
2017-11-13 23:46           ` Stefan Beller
2017-11-10 19:05 ` [PATCH 03/30] merge-recursive: Add explanation for src_entry and dst_entry Elijah Newren
2017-11-13 21:06   ` Stefan Beller [this message]
2017-11-13 22:57     ` Elijah Newren
2017-11-13 23:11       ` Stefan Beller
2017-11-14  1:26   ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 04/30] directory rename detection: basic testcases Elijah Newren
2017-11-13 22:04   ` Stefan Beller
2017-11-14  0:57     ` Elijah Newren
2017-11-14  1:21       ` Stefan Beller
2017-11-14  1:40         ` Elijah Newren
2017-11-14  2:03     ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 05/30] directory rename detection: directory splitting testcases Elijah Newren
2017-11-13 23:20   ` Stefan Beller
2017-11-10 19:05 ` [PATCH 06/30] directory rename detection: testcases to avoid taking detection too far Elijah Newren
2017-11-13 23:25   ` Stefan Beller
2017-11-14  1:02     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 07/30] directory rename detection: partially renamed directory testcase/discussion Elijah Newren
2017-11-14  0:07   ` Stefan Beller
2017-11-10 19:05 ` [PATCH 08/30] directory rename detection: files/directories in the way of some renames Elijah Newren
2017-11-14  0:15   ` Stefan Beller
2017-11-14  1:19     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 09/30] directory rename detection: testcases checking which side did the rename Elijah Newren
2017-11-14  0:25   ` Stefan Beller
2017-11-14  1:30     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 10/30] directory rename detection: more involved edge/corner testcases Elijah Newren
2017-11-14  0:42   ` Stefan Beller
2017-11-14 21:11     ` Elijah Newren
2017-11-14 22:47       ` Stefan Beller
2017-11-10 19:05 ` [PATCH 11/30] directory rename detection: testcases exploring possibly suboptimal merges Elijah Newren
2017-11-14 20:33   ` Stefan Beller
2017-11-14 21:42     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 12/30] directory rename detection: miscellaneous testcases to complete coverage Elijah Newren
2017-11-15 20:03   ` Stefan Beller
2017-11-16 21:17     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 13/30] directory rename detection: tests for handling overwriting untracked files Elijah Newren
2017-11-10 19:05 ` [PATCH 14/30] directory rename detection: tests for handling overwriting dirty files Elijah Newren
2017-11-10 19:05 ` [PATCH 15/30] merge-recursive: Move the get_renames() function Elijah Newren
2017-11-14  4:46   ` Junio C Hamano
2017-11-14 17:41     ` Elijah Newren
2017-11-15  1:20       ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 16/30] merge-recursive: Introduce new functions to handle rename logic Elijah Newren
2017-11-14  4:56   ` Junio C Hamano
2017-11-14  5:14     ` Junio C Hamano
2017-11-14 18:24       ` Elijah Newren
2017-11-10 19:05 ` [PATCH 17/30] merge-recursive: Fix leaks of allocated renames and diff_filepairs Elijah Newren
2017-11-14  4:58   ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 18/30] merge-recursive: Make !o->detect_rename codepath more obvious Elijah Newren
2017-11-10 19:05 ` [PATCH 19/30] merge-recursive: Split out code for determining diff_filepairs Elijah Newren
2017-11-14  5:20   ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 20/30] merge-recursive: Add a new hashmap for storing directory renames Elijah Newren
2017-11-10 19:05 ` [PATCH 21/30] merge-recursive: Add get_directory_renames() Elijah Newren
2017-11-14  5:30   ` Junio C Hamano
2017-11-14 18:38     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 22/30] merge-recursive: Check for directory level conflicts Elijah Newren
2017-11-10 19:05 ` [PATCH 23/30] merge-recursive: Add a new hashmap for storing file collisions Elijah Newren
2017-11-10 19:05 ` [PATCH 24/30] merge-recursive: Add computation of collisions due to dir rename & merging Elijah Newren
2018-06-10 10:56   ` René Scharfe
2018-06-10 11:03     ` René Scharfe
2018-06-10 20:44     ` Jeff King
2018-06-11 15:03     ` Elijah Newren
2018-06-14 17:36     ` Junio C Hamano
2017-11-10 19:05 ` [PATCH 25/30] merge-recursive: Check for file level conflicts then get new name Elijah Newren
2017-11-10 19:05 ` [PATCH 26/30] merge-recursive: When comparing files, don't include trees Elijah Newren
2017-11-10 19:05 ` [PATCH 27/30] merge-recursive: Apply necessary modifications for directory renames Elijah Newren
2017-11-15 20:23   ` Stefan Beller
2017-11-16  3:54     ` Elijah Newren
2017-11-10 19:05 ` [PATCH 28/30] merge-recursive: Avoid clobbering untracked files with " Elijah Newren
2017-11-10 19:05 ` [RFC PATCH 29/30] merge-recursive: Fix overwriting dirty files involved in renames Elijah Newren
2017-11-10 19:05 ` [PATCH 30/30] merge-recursive: Fix remaining directory rename + dirty overwrite cases Elijah Newren
2017-11-10 22:27 ` [PATCH 00/30] Add directory rename detection to git Philip Oakley
2017-11-10 23:26   ` Elijah Newren
2017-11-13 15:04     ` Philip Oakley

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