Subject: [PATCH v2 0/3] Fix bugs from interesting renaming pairs: one side renames A/file -> B/file, the other B/ -> A/

From: "Elijah Newren via GitGitGadget" <[email-masked]>
Date: Wed, 30 Jun 2021 17:29:57 +0000

Anders Kaseorg recently reported a few issues in an interesting rename
case[1]. I was able to duplicate and find multiple bugs from it; two in
merge-recursive, and one in merge-ort. This series has some fixes.

Changes since v1:

 * Added a third testcase

[1]
https://lore.kernel.org/git/CABPp-BGDfucqae=HNES_QmmsjpDbdHrR6CG=[email-masked]/

Elijah Newren (3):
  t6423: test directory renames causing rename-to-self
  merge-ort: ensure we consult df_conflict and path_conflicts
  merge-recursive: handle rename-to-self case

 merge-ort.c                         |   6 +-
 merge-recursive.c                   |  19 ++-
 t/t6423-merge-rename-directories.sh | 175 ++++++++++++++++++++++++++++
 3 files changed, 193 insertions(+), 7 deletions(-)

base-commit: 670b81a890388c60b7032a4f5b879f2ece8c4558
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1039%2Fnewren%2Frename-plus-dir-rename-cancel-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1039/newren/rename-plus-dir-rename-cancel-v2
Pull-Request: https://github.com/git/git/pull/1039

Range-diff vs v1:

 1:  d3572e8bc85 ! 1:  86b2eaea75e t6423: test directory renames causing rename-to-self
     @@ t/t6423-merge-rename-directories.sh: test_expect_failure '12h: renaming a file w
      +		test_cmp expect actual
      +	)
      +'
     ++
     ++# Testcase 12k, Directory rename with sibling causes rename-to-self
     ++#   Commit O: dirB/foo, dirA/{bar, baz_1}
     ++#   Commit A: dirA/{foo, bar, baz_1}
     ++#   Commit B: dirB/{foo, bar}, dirA/baz_2
     ++#   Expected: dirA/{foo, bar, baz_2}, with conflicts on dirA/bar vs. dirB/bar
     ++
     ++test_setup_12k () {
     ++	test_create_repo 12k &&
     ++	(
     ++		cd 12k &&
     ++
     ++		mkdir dirA dirB &&
     ++		echo foo >dirB/foo &&
     ++		echo bar >dirA/bar &&
     ++		echo baz >dirA/baz &&
     ++		git add . &&
     ++		git commit -m orig &&
     ++
     ++		git branch O &&
     ++		git branch A &&
     ++		git branch B &&
     ++
     ++		git switch A &&
     ++		git mv dirB/* dirA/ &&
     ++		git commit -m A &&
     ++
     ++		git switch B &&
     ++		git mv dirA/bar dirB/bar &&
     ++		echo more baz >>dirA/baz &&
     ++		git commit -m B
     ++	)
     ++}
     ++
     ++test_expect_merge_algorithm failure failure '12k: Directory rename with sibling causes rename-to-self' '
     ++	test_setup_12k &&
     ++	(
     ++		cd 12k &&
     ++
     ++		git checkout A^0 &&
     ++
     ++		test_must_fail git -c merge.directoryRenames=conflict merge -s recursive B^0 &&
     ++
     ++		test_path_is_missing dirB &&
     ++		test_path_is_file dirA/bar &&
     ++		test_path_is_file dirA/baz &&
     ++
     ++		git ls-files | uniq >tracked &&
     ++		test_line_count = 3 tracked &&
     ++
     ++		git status --porcelain -uno >actual &&
     ++		cat >expect <<-\EOF &&
     ++		UU dirA/bar
     ++		 M dirA/baz
     ++		EOF
     ++		test_cmp expect actual
     ++	)
     ++'
      +
       ###########################################################################
       # SECTION 13: Checking informational and conflict messages
 2:  052f40c3c1a ! 2:  6e7ef18bf53 merge-ort: ensure we consult df_conflict and path_conflicts
     @@ t/t6423-merge-rename-directories.sh: test_setup_12j () {
       	test_setup_12j &&
       	(
       		cd 12j &&
     +@@ t/t6423-merge-rename-directories.sh: test_setup_12k () {
     + 	)
     + }
     + 
     +-test_expect_merge_algorithm failure failure '12k: Directory rename with sibling causes rename-to-self' '
     ++test_expect_merge_algorithm failure success '12k: Directory rename with sibling causes rename-to-self' '
     + 	test_setup_12k &&
     + 	(
     + 		cd 12k &&
 3:  dea97c25e52 ! 3:  7c96d6c7a0a merge-recursive: handle rename-to-self case
     @@ t/t6423-merge-rename-directories.sh: test_setup_12j () {
       	test_setup_12j &&
       	(
       		cd 12j &&
     +@@ t/t6423-merge-rename-directories.sh: test_setup_12k () {
     + 	)
     + }
     + 
     +-test_expect_merge_algorithm failure success '12k: Directory rename with sibling causes rename-to-self' '
     ++test_expect_success '12k: Directory rename with sibling causes rename-to-self' '
     + 	test_setup_12k &&
     + 	(
     + 		cd 12k &&

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