From: Elijah Newren <newren@gmail.com>
To: git@vger.kernel.org
Cc: Elijah Newren <newren@gmail.com>
Subject: [PATCH 11/30] directory rename detection: testcases exploring possibly suboptimal merges
Date: Fri, 10 Nov 2017 11:05:31 -0800 [thread overview]
Message-ID: <20171110190550.27059-12-newren@gmail.com> (raw)
In-Reply-To: <20171110190550.27059-1-newren@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
---
t/t6043-merge-rename-directories.sh | 371 ++++++++++++++++++++++++++++++++++++
1 file changed, 371 insertions(+)
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
index 115d0d2622..bdfd943c88 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6043-merge-rename-directories.sh
@@ -1683,4 +1683,375 @@ test_expect_failure '7e-check: transitive rename in rename/delete AND dirs in th
test $(git hash-object y/d~C^0) = $(git rev-parse A:x/d)
'
+
+###########################################################################
+# SECTION 8: Suboptimal merges
+#
+# As alluded to in the last section, the ruleset we have built up for
+# detecting directory renames unfortunately has some special cases where it
+# results in slightly suboptimal or non-intuitive behavior. This section
+# explores these cases.
+#
+# To be fair, we already had non-intuitive or suboptimal behavior for most
+# of these cases in git before introducing implicit directory rename
+# detection, but it'd be nice if there was a modified ruleset out there
+# that handled these cases a bit better.
+###########################################################################
+
+# Testcase 8a, Dual-directory rename, one into the others' way
+# Commit A. x/{a,b}, y/{c,d}
+# Commit B. x/{a,b,e}, y/{c,d,f}
+# Commit C. y/{a,b}, z/{c,d}
+#
+# Possible Resolutions:
+# Previous git: y/{a,b,f}, z/{c,d}, x/e
+# Expected: y/{a,b,e,f}, z/{c,d}
+# Preferred: y/{a,b,e}, z/{c,d,f}
+#
+# Note: Both x and y got renamed and it'd be nice to detect both, and we do
+# better with directory rename detection than git did previously, but the
+# simple rule from section 5 prevents me from handling this as optimally as
+# we potentially could.
+
+test_expect_success '8a-setup: Dual-directory rename, one into the others way' '
+ git rm -rf . &&
+ git clean -fdqx &&
+ rm -rf .git &&
+ git init &&
+
+ mkdir x &&
+ mkdir y &&
+ echo a >x/a &&
+ echo b >x/b &&
+ echo c >y/c &&
+ echo d >y/d &&
+ git add x y &&
+ test_tick &&
+ git commit -m "A" &&
+
+ git branch A &&
+ git branch B &&
+ git branch C &&
+
+ git checkout B &&
+ echo e >x/e &&
+ echo f >y/f &&
+ git add x/e y/f &&
+ test_tick &&
+ git commit -m "B" &&
+
+ git checkout C &&
+ git mv y z &&
+ git mv x y &&
+ test_tick &&
+ git commit -m "C"
+'
+
+test_expect_failure '8a-check: Dual-directory rename, one into the others way' '
+ git checkout B^0 &&
+
+ git merge -s recursive C^0 &&
+
+ test 6 -eq $(git ls-files -s | wc -l) &&
+ test 0 -eq $(git ls-files -u | wc -l) &&
+ test 0 -eq $(git ls-files -o | wc -l) &&
+
+ test $(git rev-parse HEAD:y/a) = $(git rev-parse A:x/a) &&
+ test $(git rev-parse HEAD:y/b) = $(git rev-parse A:x/b) &&
+ test $(git rev-parse HEAD:y/e) = $(git rev-parse B:x/e) &&
+ test $(git rev-parse HEAD:y/f) = $(git rev-parse B:y/f) &&
+ test $(git rev-parse HEAD:z/c) = $(git rev-parse A:y/c) &&
+ test $(git rev-parse HEAD:z/d) = $(git rev-parse A:y/d)
+'
+
+# Testcase 8b, Dual-directory rename, one into the others' way, with conflicting filenames
+# Commit A. x/{a_1,b_1}, y/{a_2,b_2}
+# Commit B. x/{a_1,b_1,e_1}, y/{a_2,b_2,e_2}
+# Commit C. y/{a_1,b_1}, z/{a_2,b_2}
+#
+# Possible Resolutions:
+# Previous git: y/{a_1,b_1,e_2}, z/{a_2,b_2}, x/e_1
+# Scary: y/{a_1,b_1}, z/{a_2,b_2}, CONFLICT(add/add, e_1 vs. e_2)
+# Preferred: y/{a_1,b_1,e_1}, z/{a_2,b_2,e_2}
+#
+# Note: Very similar to 8a, except instead of 'e' and 'f' in directories x and
+# y, both are named 'e'. Without directory rename detection, neither file
+# moves directories. Implment directory rename detection suboptimally, and
+# you get an add/add conflict, but both files were added in commit B, so this
+# is an add/add conflict where one side of history added both files --
+# something we can't represent in the index. Obviously, we'd prefer the last
+# resolution, but our previous rules are too coarse to allow it. Using both
+# the rules from section 4 and section 5 save us from the Scary resolution,
+# making us fall back to pre-directory-rename-detection behavior for both
+# e_1 and e_2.
+
+test_expect_success '8b-setup: Dual-directory rename, one into the others way, with conflicting filenames' '
+ git rm -rf . &&
+ git clean -fdqx &&
+ rm -rf .git &&
+ git init &&
+
+ mkdir x &&
+ mkdir y &&
+ echo a1 >x/a &&
+ echo b1 >x/b &&
+ echo a2 >y/a &&
+ echo b2 >y/b &&
+ git add x y &&
+ test_tick &&
+ git commit -m "A" &&
+
+ git branch A &&
+ git branch B &&
+ git branch C &&
+
+ git checkout B &&
+ echo e1 >x/e &&
+ echo e2 >y/e &&
+ git add x/e y/e &&
+ test_tick &&
+ git commit -m "B" &&
+
+ git checkout C &&
+ git mv y z &&
+ git mv x y &&
+ test_tick &&
+ git commit -m "C"
+'
+
+test_expect_success '8b-check: Dual-directory rename, one into the others way, with conflicting filenames' '
+ git checkout B^0 &&
+
+ git merge -s recursive C^0 &&
+
+ test 6 -eq $(git ls-files -s | wc -l) &&
+ test 0 -eq $(git ls-files -u | wc -l) &&
+ test 0 -eq $(git ls-files -o | wc -l) &&
+
+ test $(git rev-parse HEAD:y/a) = $(git rev-parse A:x/a) &&
+ test $(git rev-parse HEAD:y/b) = $(git rev-parse A:x/b) &&
+ test $(git rev-parse HEAD:z/a) = $(git rev-parse A:y/a) &&
+ test $(git rev-parse HEAD:z/b) = $(git rev-parse A:y/b) &&
+ test $(git rev-parse HEAD:x/e) = $(git rev-parse B:x/e) &&
+ test $(git rev-parse HEAD:y/e) = $(git rev-parse B:y/e)
+'
+
+# Testcase 8c, rename+modify/delete
+# (Related to testcases 5b and 8d)
+# Commit A: z/{b,c,d}
+# Commit B: y/{b,c}
+# Commit C: z/{b,c,d_modified,e}
+# Expected: y/{b,c,e}, CONFLICT(rename+modify/delete: x/d -> y/d or deleted)
+#
+# Note: This testcase doesn't present any concerns for me...until you
+# compare it with testcases 5b and 8d. See notes in 8d for more
+# details.
+
+test_expect_success '8c-setup: rename+modify/delete' '
+ git rm -rf . &&
+ git clean -fdqx &&
+ rm -rf .git &&
+ git init &&
+
+ mkdir z &&
+ echo b >z/b &&
+ echo c >z/c &&
+ test_seq 1 10 >z/d &&
+ git add z &&
+ test_tick &&
+ git commit -m "A" &&
+
+ git branch A &&
+ git branch B &&
+ git branch C &&
+
+ git checkout B &&
+ git rm z/d &&
+ git mv z y &&
+ test_tick &&
+ git commit -m "B" &&
+
+ git checkout C &&
+ echo 11 >z/d &&
+ test_chmod +x z/d &&
+ echo e >z/e &&
+ git add z/d z/e &&
+ test_tick &&
+ git commit -m "C"
+'
+
+test_expect_failure '8c-check: rename+modify/delete' '
+ git checkout B^0 &&
+
+ test_must_fail git merge -s recursive C^0 >out &&
+ test_i18ngrep "CONFLICT (rename/delete).* z/d.*y/d" out &&
+
+ test 4 -eq $(git ls-files -s | wc -l) &&
+ test 1 -eq $(git ls-files -u | wc -l) &&
+ test 1 -eq $(git ls-files -o | wc -l) &&
+
+ test $(git rev-parse :0:y/b) = $(git rev-parse A:z/b) &&
+ test $(git rev-parse :0:y/c) = $(git rev-parse A:z/c) &&
+ test $(git rev-parse :0:y/e) = $(git rev-parse C:z/e) &&
+
+ test_must_fail git rev-parse :1:y/d &&
+ test_must_fail git rev-parse :2:y/d &&
+ test $(git rev-parse :3:y/d) = $(git rev-parse C:z/d) &&
+ git ls-files -s y/d | grep ^100755 &&
+ test -f y/d
+'
+
+# Testcase 8d, rename/delete...or not?
+# (Related to testcase 5b; these may appear slightly inconsistent to users;
+# Also related to testcases 7d and 7e)
+# Commit A: z/{b,c,d}
+# Commit B: y/{b,c}
+# Commit C: z/{b,c,d,e}
+# Expected: y/{b,c,e}
+#
+# Note: It would also be somewhat reasonable to resolve this as
+# y/{b,c,e}, CONFLICT(rename/delete: x/d -> y/d or deleted)
+# The logic being that the only difference between this testcase and 8c
+# is that there is no modification to d. That suggests that instead of a
+# rename/modify vs. delete conflict, we should just have a rename/delete
+# conflict, otherwise we are being inconsistent.
+#
+# However...as far as consistency goes, we didn't report a conflict for
+# path d_1 in testcase 5b due to a different file being in the way. So,
+# we seem to be forced to have cases where users can change things
+# slightly and get what they may perceive as inconsistent results. It
+# would be nice to avoid that, but I'm not sure I see how.
+#
+# In this case, I'm leaning towards: commit B was the one that deleted z/d
+# and it did the rename of z to y, so the two "conflicts" (rename vs.
+# delete) are both coming from commit B, which is non-sensical. Conflicts
+# during merging are supposed to be about opposite sides doing things
+# differently.
+
+test_expect_success '8d-setup: rename/delete...or not?' '
+ git rm -rf . &&
+ git clean -fdqx &&
+ rm -rf .git &&
+ git init &&
+
+ mkdir z &&
+ echo b >z/b &&
+ echo c >z/c &&
+ test_seq 1 10 >z/d &&
+ git add z &&
+ test_tick &&
+ git commit -m "A" &&
+
+ git branch A &&
+ git branch B &&
+ git branch C &&
+
+ git checkout B &&
+ git rm z/d &&
+ git mv z y &&
+ test_tick &&
+ git commit -m "B" &&
+
+ git checkout C &&
+ echo e >z/e &&
+ git add z/e &&
+ test_tick &&
+ git commit -m "C"
+'
+
+test_expect_failure '8d-check: rename/delete...or not?' '
+ git checkout B^0 &&
+
+ git merge -s recursive C^0 &&
+
+ test 3 -eq $(git ls-files -s | wc -l) &&
+
+ test $(git rev-parse HEAD:y/b) = $(git rev-parse A:z/b) &&
+ test $(git rev-parse HEAD:y/c) = $(git rev-parse A:z/c) &&
+ test $(git rev-parse HEAD:y/e) = $(git rev-parse C:z/e)
+'
+
+# Testcase 8e, Both sides rename, one side adds to original directory
+# Commit A: z/{b,c}
+# Commit B: y/{b,c}
+# Commit C: w/{b,c}, z/d
+#
+# Possible Resolutions:
+# Previous git: z/d, CONFLICT(z/b -> y/b vs. w/b), CONFLICT(z/c -> y/c vs. w/c)
+# Expected: y/d, CONFLICT(z/b -> y/b vs. w/b), CONFLICT(z/c -> y/c vs. w/c)
+# Preferred: ??
+#
+# Notes: In commit B, directory z got renamed to y. In commit C, directory z
+# did NOT get renamed; the directory is still present; instead it is
+# considered to have just renamed a subset of paths in directory z
+# elsewhere. Therefore, the directory rename done in commit B to z/
+# applies to z/d and maps it to y/d.
+#
+# It's possible that users would get confused about this, but what
+# should we do instead? Silently leaving at z/d seems just as bad or
+# maybe even worse. Perhaps we could print a big warning about z/d
+# and how we're moving to y/d in this case, but when I started thinking
+# abouty the ramifications of doing that, I didn't know how to rule out
+# that opening other weird edge and corner cases so I just punted.
+
+test_expect_success '8e-setup: Both sides rename, one side adds to original directory' '
+ git rm -rf . &&
+ git clean -fdqx &&
+ rm -rf .git &&
+ git init &&
+
+ mkdir z &&
+ echo b >z/b &&
+ echo c >z/c &&
+ git add z &&
+ test_tick &&
+ git commit -m "A" &&
+
+ git branch A &&
+ git branch B &&
+ git branch C &&
+
+ git checkout B &&
+ git mv z y &&
+ test_tick &&
+ git commit -m "B" &&
+
+ git checkout C &&
+ git mv z w &&
+ mkdir z &&
+ echo d >z/d &&
+ git add z/d &&
+ test_tick &&
+ git commit -m "C"
+'
+
+test_expect_failure '8e-check: Both sides rename, one side adds to original directory' '
+ git checkout B^0 &&
+
+ test_must_fail git merge -s recursive C^0 >out 2>err &&
+
+ test 7 -eq $(git ls-files -s | wc -l) &&
+ test 6 -eq $(git ls-files -u | wc -l) &&
+ test 2 -eq $(git ls-files -o | wc -l) &&
+
+ test $(git rev-parse :0:y/d) = $(git rev-parse C:z/d) &&
+
+ test $(git rev-parse :1:z/b) = $(git rev-parse A:z/b) &&
+ test $(git rev-parse :2:y/b) = $(git rev-parse A:z/b) &&
+ test $(git rev-parse :3:w/b) = $(git rev-parse A:z/b) &&
+ test ! -f z/b &&
+ test $(git hash-object y/b) = $(git rev-parse A:z/b) &&
+ test $(git hash-object w/b) = $(git rev-parse A:z/b) &&
+
+ test $(git rev-parse :1:z/c) = $(git rev-parse A:z/c) &&
+ test $(git rev-parse :2:y/c) = $(git rev-parse A:z/c) &&
+ test $(git rev-parse :3:w/c) = $(git rev-parse A:z/c) &&
+ test ! -f z/c &&
+ test $(git hash-object y/c) = $(git rev-parse A:z/c) &&
+ test $(git hash-object w/c) = $(git rev-parse A:z/c) &&
+
+ test_i18ngrep CONFLICT.*rename/rename.*z/c.*y/c.*w/c out &&
+ test_i18ngrep CONFLICT.*rename/rename.*z/b.*y/b.*w/b out
+'
+
test_done
--
2.15.0.5.g9567be9905
next prev parent reply other threads:[~2017-11-10 19:06 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
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 ` Elijah Newren [this message]
2017-11-14 20:33 ` [PATCH 11/30] directory rename detection: testcases exploring possibly suboptimal merges 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171110190550.27059-12-newren@gmail.com \
--to=newren@gmail.com \
--cc=git@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).