test that git status works with merge conflict in, .gitmodules

For example: Two users independently adding a submodule will result in a
merge conflict in .gitmodules. Since configuration of the status and
diff machinery depends on the file being parseable they currently
fail to produce useable output in case .gitmodules is marked with a
merge conflict.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7506-status-submodule.sh

@@ -4,17 +4,21 @@ test_description='git status for submodule'
 
 . ./test-lib.sh
 
-test_expect_success 'setup' '
-	test_create_repo sub &&
+test_create_repo_with_commit () {
+	test_create_repo "$1" &&
 	(
-		cd sub &&
+		cd "$1" &&
 		: >bar &&
 		git add bar &&
 		git commit -m " Add bar" &&
 		: >foo &&
 		git add foo &&
 		git commit -m " Add foo"
-	) &&
+	)
+}
+
+test_expect_success 'setup' '
+	test_create_repo_with_commit sub &&
 	echo output > .gitignore &&
 	git add sub .gitignore &&
 	git commit -m "Add submodule sub"
@@ -187,4 +191,84 @@ test_expect_success C_LOCALE_OUTPUT 'status -a clean (empty submodule dir)' '
 	grep "nothing to commit" output
 '
 
+cat >status_expect <<\EOF
+AA .gitmodules
+A  sub1
+EOF
+
+test_expect_failure 'status with merge conflict in .gitmodules' '
+	git clone . super &&
+	test_create_repo_with_commit sub1 &&
+	test_tick &&
+	test_create_repo_with_commit sub2 &&
+	(
+		cd super &&
+		prev=$(git rev-parse HEAD) &&
+		git checkout -b add_sub1 &&
+		git submodule add ../sub1 &&
+		git commit -m "add sub1" &&
+		git checkout -b add_sub2 $prev &&
+		git submodule add ../sub2 &&
+		git commit -m "add sub2" &&
+		git checkout -b merge_conflict_gitmodules &&
+		test_must_fail git merge add_sub1 &&
+		git status -s >../status_actual 2>&1
+	) &&
+	test_cmp status_actual status_expect
+'
+
+sha1_merge_sub1=$(cd sub1 && git rev-parse HEAD)
+sha1_merge_sub2=$(cd sub2 && git rev-parse HEAD)
+short_sha1_merge_sub1=$(cd sub1 && git rev-parse --short HEAD)
+short_sha1_merge_sub2=$(cd sub2 && git rev-parse --short HEAD)
+cat >diff_expect <<\EOF
+diff --cc .gitmodules
+index badaa4c,44f999a..0000000
+--- a/.gitmodules
++++ b/.gitmodules
+@@@ -1,3 -1,3 +1,9 @@@
+++<<<<<<< HEAD
+ +[submodule "sub2"]
+ +	path = sub2
+ +	url = ../sub2
+++=======
++ [submodule "sub1"]
++ 	path = sub1
++ 	url = ../sub1
+++>>>>>>> add_sub1
+EOF
+
+cat >diff_submodule_expect <<\EOF
+diff --cc .gitmodules
+index badaa4c,44f999a..0000000
+--- a/.gitmodules
++++ b/.gitmodules
+@@@ -1,3 -1,3 +1,9 @@@
+++<<<<<<< HEAD
+ +[submodule "sub2"]
+ +	path = sub2
+ +	url = ../sub2
+++=======
++ [submodule "sub1"]
++ 	path = sub1
++ 	url = ../sub1
+++>>>>>>> add_sub1
+EOF
+
+test_expect_failure 'diff with merge conflict in .gitmodules' '
+	(
+		cd super &&
+		git diff >../diff_actual 2>&1
+	) &&
+	test_cmp diff_actual diff_expect
+'
+
+test_expect_failure 'diff --submodule with merge conflict in .gitmodules' '
+	(
+		cd super &&
+		git diff --submodule >../diff_submodule_actual 2>&1
+	) &&
+	test_cmp diff_submodule_actual diff_submodule_expect
+'
+
 test_done