mv: Fix spurious warning when moving a file in presence of submodules

In commit 0656781fa "git mv" learned to update the submodule path in the
.gitmodules file when moving a submodule in the work tree. But since that
commit update_path_in_gitmodules() gets called no matter if we moved a
submodule or a regular file, which is wrong and leads to a bogus warning
when moving a regular file in a repo containing a .gitmodules file:

    warning: Could not find section in .gitmodules where path=<filename>

Fix that by only calling update_path_in_gitmodules() when moving a
submodule. To achieve that, we introduce the special SUBMODULE_WITH_GITDIR
define to distinguish the cases where we also have to connect work tree
and git directory from those where we only need to update the .gitmodules
setting.

A test for submodules using a .git directory together with a .gitmodules
file has been added to t7001. Even though newer git versions will always
use a gitfile when cloning submodules, repositories cloned with older git
versions will still use this layout.

Reported-by: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>

builtin/mv.c

@@ -55,6 +55,7 @@ static const char *add_slash(const char *path)
 }
 
 static struct lock_file lock_file;
+#define SUBMODULE_WITH_GITDIR ((const char *)1)
 
 int cmd_mv(int argc, const char **argv, const char *prefix)
 {
@@ -132,6 +133,8 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 				submodule_gitfile[i] = read_gitfile(submodule_dotgit.buf);
 				if (submodule_gitfile[i])
 					submodule_gitfile[i] = xstrdup(submodule_gitfile[i]);
+				else
+					submodule_gitfile[i] = SUBMODULE_WITH_GITDIR;
 				strbuf_release(&submodule_dotgit);
 			} else {
 				const char *src_w_slash = add_slash(src);
@@ -230,10 +233,12 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 		if (!show_only && mode != INDEX) {
 			if (rename(src, dst) < 0 && !ignore_errors)
 				die_errno (_("renaming '%s' failed"), src);
-			if (submodule_gitfile[i])
-				connect_work_tree_and_git_dir(dst, submodule_gitfile[i]);
-			if (!update_path_in_gitmodules(src, dst))
-				gitmodules_modified = 1;
+			if (submodule_gitfile[i]) {
+				if (submodule_gitfile[i] != SUBMODULE_WITH_GITDIR)
+					connect_work_tree_and_git_dir(dst, submodule_gitfile[i]);
+				if (!update_path_in_gitmodules(src, dst))
+					gitmodules_modified = 1;
+			}
 		}
 
 		if (mode == WORKING_DIRECTORY)

t/t7001-mv.sh

@@ -293,6 +293,32 @@ test_expect_success 'git mv moves a submodule with a .git directory and no .gitm
 	git diff-files --quiet
 '
 
+test_expect_success 'git mv moves a submodule with a .git directory and .gitmodules' '
+	rm -rf mod &&
+	git reset --hard &&
+	git submodule update &&
+	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	(
+		cd sub &&
+		rm -f .git &&
+		cp -a ../.git/modules/sub .git &&
+		GIT_WORK_TREE=. git config --unset core.worktree
+	) &&
+	mkdir mod &&
+	git mv sub mod/sub &&
+	! test -e sub &&
+	[ "$entry" = "$(git ls-files --stage mod/sub | cut -f 1)" ] &&
+	(
+		cd mod/sub &&
+		git status
+	) &&
+	echo mod/sub >expected &&
+	git config -f .gitmodules submodule.sub.path >actual &&
+	test_cmp expected actual &&
+	git update-index --refresh &&
+	git diff-files --quiet
+'
+
 test_expect_success 'git mv moves a submodule with gitfile' '
 	rm -rf mod/sub &&
 	git reset --hard &&