submodule--helper: fix a leak in "clone_submodule"

Fix a memory leak of the "clone_data_path" variable that we copy or
derive from the "struct module_clone_data" in clone_submodule(). This
code was refactored in preceding commits, but the leak has been with
us since f8eaa0ba98b (submodule--helper, module_clone: always operate
on absolute paths, 2016-03-31).

For the "else" case we don't need to xstrdup() the "clone_data->path",
and we don't need to free our own "clone_data_path". We can therefore
assign the "clone_data->path" to our own "clone_data_path" right away,
and only override it (and remember to free it!) if we need to
xstrfmt() a replacement.

In the case of the module_clone() caller it's from "argv", and doesn't
need to be free'd, and in the case of the add_submodule() caller we
get a pointer to "sm_path", which doesn't need to be directly free'd
either.

Fixing this leak makes several tests pass, so let's mark them as
passing with TEST_PASSES_SANITIZE_LEAK=true.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 3a2a92da51..d308b14904 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1587,13 +1587,12 @@ static int clone_submodule(const struct module_clone_data *clone_data,
 	char *sm_gitdir = clone_submodule_sm_gitdir(clone_data->name);
 	char *sm_alternate = NULL, *error_strategy = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
-	const char *clone_data_path;
+	const char *clone_data_path = clone_data->path;
+	char *to_free = NULL;
 
 	if (!is_absolute_path(clone_data->path))
-		clone_data_path = xstrfmt("%s/%s", get_git_work_tree(),
-					  clone_data->path);
-	else
-		clone_data_path = xstrdup(clone_data->path);
+		clone_data_path = to_free = xstrfmt("%s/%s", get_git_work_tree(),
+						    clone_data->path);
 
 	if (validate_submodule_git_dir(sm_gitdir, clone_data->name) < 0)
 		die(_("refusing to create/use '%s' in another submodule's "
@@ -1678,6 +1677,7 @@ static int clone_submodule(const struct module_clone_data *clone_data,
 
 	free(sm_gitdir);
 	free(p);
+	free(to_free);
 	return 0;
 }