2 files changed, 80 insertions, 3 deletions
diff --git a/merge-ort.c b/merge-ort.c
index 325b19b182..e7bdcf7b96 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -2879,6 +2879,20 @@ static int process_renames(struct merge_options *opt,
 		}
 
 		/*
+		 * Directory renames can result in rename-to-self; the code
+		 * below assumes we have A->B with different A & B, and tries
+		 * to move all entries to path B.  If A & B are the same path,
+		 * the logic can get confused, so skip further processing when
+		 * A & B are already the same path.
+		 *
+		 * As a reminder, we can avoid strcmp here because all paths
+		 * are interned in opt->priv->paths; see the comment above
+		 * "paths" in struct merge_options_internal.
+		 */
+		if (oldpath == newpath)
+			continue;
+
+		/*
 		 * If pair->one->path isn't in opt->priv->paths, that means
 		 * that either directory rename detection removed that
 		 * path, or a parent directory of oldpath was resolved and
diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index e1251b4e12..49eb10392b 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 &&