[PATCH v2 5/6] merge-ort: fix incorrect file handling

From

Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>

Date

Aug 5, 2025, 19:35 UTC

Message-ID

<a8a7535fa5ed9c609c5f0f6db9ea135e2fb02a62.1754422546.git.gitgitgadget@gmail.com>

In-Reply-To

<pull.1943.v2.git.1754422546.gitgitgadget@gmail.com>

From: Elijah Newren <newren@gmail.com>

In summary, we have the following bugs with rename-to-self cases:
  * silent deletion of file expected to be kept (t6423 testcase 12i2)
  * silent retention of file expected to be removed (t6423 testcase 12n2)
  * wrong number of extries left in the index (t6423 testcase 12n)

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-ort.c                         | 11 +++++
 t/t6423-merge-rename-directories.sh | 69 +++++++++++++++++++++++++++--
 2 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/merge-ort.c b/merge-ort.c
index 9b9d82ed10f7..feb06720c7e1 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -2873,6 +2873,17 @@ static int process_renames(struct merge_options *opt,
 			newinfo = new_ent->value;
 		}
 
+		/*
+		 * Directory renames can result in rename-to-self, which we
+		 * want to skip so we don't mark oldpath for deletion.
+		 *
+		 * Note that we can avoid strcmp here because of prior
+		 * diligence in apply_directory_rename_modifications() to
+		 * ensure we reused existing paths from opt->priv->paths.
+		 */
+		if (oldpath == newpath)
+			continue;
+
 		/*
 		 * If pair->one->path isn't in opt->priv->paths, that means
 		 * that either directory rename detection removed that
diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index e1251b4e12ce..49eb10392bed 100755
--- a/t/t6423-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -4731,7 +4731,7 @@ test_setup_12i () {
 
 		mkdir -p source/subdir &&
 		echo foo >source/subdir/foo &&
-		echo bar >source/bar &&
+		printf "%d\n" 1 2 3 4 5 6 7 >source/bar &&
 		echo baz >source/baz &&
 		git add source &&
 		git commit -m orig &&
@@ -4778,6 +4778,69 @@ test_expect_success '12i: Directory rename causes rename-to-self' '
 	)
 '
 
+# Testcase 12i2, Identical to 12i except that source/subdir/bar modified on unrenamed side
+#   Commit O: source/{subdir/foo, bar, baz_1}
+#   Commit A: source/{foo, bar_2, baz_1}
+#   Commit B: source/{subdir/{foo, bar}, baz_2}
+#   Expected: source/{foo, bar, baz_2}, with conflicts on
+#                source/bar vs. source/subdir/bar
+
+test_setup_12i2 () {
+	git init 12i2 &&
+	(
+		cd 12i2 &&
+
+		mkdir -p source/subdir &&
+		echo foo >source/subdir/foo &&
+		printf "%d\n" 1 2 3 4 5 6 7 >source/bar &&
+		echo baz >source/baz &&
+		git add source &&
+		git commit -m orig &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git switch A &&
+		git mv source/subdir/foo source/foo &&
+		echo 8 >> source/bar &&
+		git add source/bar &&
+		git commit -m A &&
+
+		git switch B &&
+		git mv source/bar source/subdir/bar &&
+		echo more baz >>source/baz &&
+		git add source/baz &&
+		git commit -m B
+	)
+}
+
+test_expect_success '12i2: Directory rename causes rename-to-self' '
+	test_setup_12i2 &&
+	(
+		cd 12i2 &&
+
+		git checkout A^0 &&
+
+		test_must_fail git -c merge.directoryRenames=conflict merge -s recursive B^0 &&
+
+		test_path_is_missing source/subdir &&
+		test_path_is_file source/bar &&
+		test_path_is_file source/baz &&
+
+		git ls-files >actual &&
+		uniq <actual >tracked &&
+		test_line_count = 3 tracked &&
+
+		git status --porcelain -uno >actual &&
+		cat >expect <<-\EOF &&
+		UU source/bar
+		M  source/baz
+		EOF
+		test_cmp expect actual
+	)
+'
+
 # Testcase 12j, Directory rename to root causes rename-to-self
 #   Commit O: {subdir/foo, bar, baz_1}
 #   Commit A: {foo, bar, baz_1}
@@ -5106,7 +5169,7 @@ test_setup_12n () {
 	)
 }
 
-test_expect_failure '12n: Directory rename transitively makes rename back to self' '
+test_expect_success '12n: Directory rename transitively makes rename back to self' '
 	test_setup_12n &&
 	(
 		cd 12n &&
@@ -5166,7 +5229,7 @@ test_setup_12n2 () {
 	)
 }
 
-test_expect_failure '12n2: Directory rename transitively makes rename back to self' '
+test_expect_success '12n2: Directory rename transitively makes rename back to self' '
 	test_setup_12n2 &&
 	(
 		cd 12n2 &&

-- 
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