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

> 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@gmail.com>
> ---
>  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)