submodule--helper: use submodule_name_to_gitdir in add_submodule

While testing submodule gitdir path encoding, I noticed submodule--helper
is still using a hardcoded modules gitdir path leading to test failures.

Call the submodule_name_to_gitdir() helper instead, which was invented
exactly for this purpose and is already used by all the other locations
which work on gitdirs.

Also narrow the scope of the submod_gitdir_path variable which is not
used anymore in the updated "else" branch.

Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: 10ne1

builtin/submodule--helper.c

@@ -3187,13 +3187,13 @@ static void append_fetch_remotes(struct strbuf *msg, const char *git_dir_path)
 
 static int add_submodule(const struct add_data *add_data)
 {
-	char *submod_gitdir_path;
 	struct module_clone_data clone_data = MODULE_CLONE_DATA_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
 	int ret = -1;
 
 	/* perhaps the path already exists and is already a git repo, else clone it */
 	if (is_directory(add_data->sm_path)) {
+		char *submod_gitdir_path;
 		struct strbuf sm_path = STRBUF_INIT;
 		strbuf_addstr(&sm_path, add_data->sm_path);
 		submod_gitdir_path = xstrfmt("%s/.git", add_data->sm_path);
@@ -3207,10 +3207,11 @@ static int add_submodule(const struct add_data *add_data)
 		free(submod_gitdir_path);
 	} else {
 		struct child_process cp = CHILD_PROCESS_INIT;
+		struct strbuf submod_gitdir = STRBUF_INIT;
 
-		submod_gitdir_path = xstrfmt(".git/modules/%s", add_data->sm_name);
+		submodule_name_to_gitdir(&submod_gitdir, the_repository, add_data->sm_name);
 
-		if (is_directory(submod_gitdir_path)) {
+		if (is_directory(submod_gitdir.buf)) {
 			if (!add_data->force) {
 				struct strbuf msg = STRBUF_INIT;
 				char *die_msg;
@@ -3219,8 +3220,8 @@ static int add_submodule(const struct add_data *add_data)
 						    "locally with remote(s):\n"),
 					    add_data->sm_name);
 
-				append_fetch_remotes(&msg, submod_gitdir_path);
-				free(submod_gitdir_path);
+				append_fetch_remotes(&msg, submod_gitdir.buf);
+				strbuf_release(&submod_gitdir);
 
 				strbuf_addf(&msg, _("If you want to reuse this local git "
 						    "directory instead of cloning again from\n"
@@ -3238,7 +3239,7 @@ static int add_submodule(const struct add_data *add_data)
 					 "submodule '%s'\n"), add_data->sm_name);
 			}
 		}
-		free(submod_gitdir_path);
+		strbuf_release(&submod_gitdir);
 
 		clone_data.prefix = add_data->prefix;
 		clone_data.path = add_data->sm_path;