[PATCH v5 16/17] submodule--helper: free rest of "displaypath" in "struct update_data"

[Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>]

Fix a leak in code added in c51f8f94e5b (submodule--helper: run update
procedures from C, 2021-08-24), we clobber the "displaypath" member of
the passed-in "struct update_data" both so that die() messages in this
update_submodule() function itself can use it, and for the
run_update_procedure() called within this function.

To make managing that clobbering easier let's wrap the
update_submodule() in a new update_submodule_outer() function, which
will do the clobbering and free(to_free) dance for us.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
 builtin/submodule--helper.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 79eca6c439b..cc8f42ae6df 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2482,13 +2482,6 @@ static int update_submodule(struct update_data *update_data)
 {
 	int ret;
 
-	ret = ensure_core_worktree(update_data->sm_path);
-	if (ret)
-		return ret;
-
-	update_data->displaypath = get_submodule_displaypath(
-		update_data->sm_path, update_data->prefix);
-
 	ret = determine_submodule_update_strategy(the_repository,
 						  update_data->just_cloned,
 						  update_data->sm_path,
@@ -2554,6 +2547,24 @@ static int update_submodule(struct update_data *update_data)
 	return 0;
 }
 
+static int update_submodule_outer(struct update_data *update_data)
+{
+	char *to_free, *restore = update_data->displaypath;
+	int ret;
+
+	ensure_core_worktree(update_data->sm_path);
+
+	update_data->displaypath = to_free = get_submodule_displaypath(
+		update_data->sm_path, update_data->prefix);
+
+	ret = update_submodule(update_data);
+
+	free(to_free);
+	update_data->displaypath = restore;
+
+	return ret;
+}
+
 static int update_submodules(struct update_data *update_data)
 {
 	int i, ret = 0;
@@ -2586,7 +2597,7 @@ static int update_submodules(struct update_data *update_data)
 		update_data->just_cloned = ucd.just_cloned;
 		update_data->sm_path = ucd.sub->path;
 
-		code = update_submodule(update_data);
+		code = update_submodule_outer(update_data);
 		if (code)
 			ret = code;
 		if (code == 128)
-- 
2.37.1.1233.ge8b09efaedc