Merge branch 'bk/submodule-in-recursive-merge'

* bk/submodule-in-recursive-merge:
  submodule: Search for merges only at end of recursive merge
  submodule: Demonstrate known breakage during recursive merge

4 files changed, 61 insertions, 4 deletions

diff --git a/merge-recursive.c b/merge-recursive.c
index c34a4f148b..cc664c39b6 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -946,8 +946,10 @@ static struct merge_file_info merge_file_1(struct merge_options *o,
 			free(result_buf.ptr);
 			result.clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result.clean = merge_submodule(result.sha, one->path, one->sha1,
-						       a->sha1, b->sha1);
+			result.clean = merge_submodule(result.sha,
+						       one->path, one->sha1,
+						       a->sha1, b->sha1,
+						       !o->call_depth);
 		} else if (S_ISLNK(a->mode)) {
 			hashcpy(result.sha, a->sha1);
 
diff --git a/submodule.c b/submodule.c
index 0b709bc291..0fd10a0fdb 100644
--- a/submodule.c
+++ b/submodule.c
@@ -794,7 +794,7 @@ static void print_commit(struct commit *commit)
 
 int merge_submodule(unsigned char result[20], const char *path,
 		    const unsigned char base[20], const unsigned char a[20],
-		    const unsigned char b[20])
+		    const unsigned char b[20], int search)
 {
 	struct commit *commit_base, *commit_a, *commit_b;
 	int parent_count;
@@ -849,6 +849,10 @@ int merge_submodule(unsigned char result[20], const char *path,
 	 * user needs to confirm the resolution.
 	 */
 
+	/* Skip the search if makes no sense to the calling context.  */
+	if (!search)
+		return 0;
+
 	/* find commit which merges them */
 	parent_count = find_first_merges(&merges, path, commit_a, commit_b);
 	switch (parent_count) {
diff --git a/submodule.h b/submodule.h
index 799c22d6c6..80e04f3c8c 100644
--- a/submodule.h
+++ b/submodule.h
@@ -28,7 +28,7 @@ int fetch_populated_submodules(int num_options, const char **options,
 			       int quiet);
 unsigned is_submodule_modified(const char *path, int ignore_untracked);
 int merge_submodule(unsigned char result[20], const char *path, const unsigned char base[20],
-		    const unsigned char a[20], const unsigned char b[20]);
+		    const unsigned char a[20], const unsigned char b[20], int search);
 int check_submodule_needs_pushing(unsigned char new_sha1[20], const char *remotes_name);
 
 #endif
diff --git a/t/t7405-submodule-merge.sh b/t/t7405-submodule-merge.sh
index a8fb30b792..0d5b42a25b 100755
--- a/t/t7405-submodule-merge.sh
+++ b/t/t7405-submodule-merge.sh
@@ -228,4 +228,55 @@ test_expect_success 'merging with a modify/modify conflict between merge bases'
 	git merge d
 '
 
+# canonical criss-cross history in top and submodule
+test_expect_success 'setup for recursive merge with submodule' '
+	mkdir merge-recursive &&
+	(cd merge-recursive &&
+	 git init &&
+	 mkdir sub &&
+	 (cd sub &&
+	  git init &&
+	  test_commit a &&
+	  git checkout -b sub-b master &&
+	  test_commit b &&
+	  git checkout -b sub-c master &&
+	  test_commit c &&
+	  git checkout -b sub-bc sub-b &&
+	  git merge sub-c &&
+	  git checkout -b sub-cb sub-c &&
+	  git merge sub-b &&
+	  git checkout master) &&
+	 git add sub &&
+	 git commit -m a &&
+	 git checkout -b top-b master &&
+	 (cd sub && git checkout sub-b) &&
+	 git add sub &&
+	 git commit -m b &&
+	 git checkout -b top-c master &&
+	 (cd sub && git checkout sub-c) &&
+	 git add sub &&
+	 git commit -m c &&
+	 git checkout -b top-bc top-b &&
+	 git merge -s ours --no-commit top-c &&
+	 (cd sub && git checkout sub-bc) &&
+	 git add sub &&
+	 git commit -m bc &&
+	 git checkout -b top-cb top-c &&
+	 git merge -s ours --no-commit top-b &&
+	 (cd sub && git checkout sub-cb) &&
+	 git add sub &&
+	 git commit -m cb)
+'
+
+# merge should leave submodule unmerged in index
+test_expect_success 'recursive merge with submodule' '
+	(cd merge-recursive &&
+	 test_must_fail git merge top-bc &&
+	 echo "160000 $(git rev-parse top-cb:sub) 2	sub" > expect2 &&
+	 echo "160000 $(git rev-parse top-bc:sub) 3	sub" > expect3 &&
+	 git ls-files -u > actual &&
+	 grep "$(cat expect2)" actual > /dev/null &&
+	 grep "$(cat expect3)" actual > /dev/null)
+'
+
 test_done