Re: [PATCH v3 30/32] submodule--helper: libify more "die" paths for module_update()

> As noted in a preceding commit the get_default_remote_submodule() and
> remote_submodule_branch() functions would invoke die(), and thus leave
> update_submodule() only partially lib-ified. Let's address the former
> of those cases.
>
> Change the functions to return an int exit code (non-zero on failure),
> while leaving the get_default_remote() function for the callers that
> still want the die() semantics.
>
> This change addresses 1/2 of the "die" issue in these two lines in
> update_submodule():
>
> 	char *remote_name = get_default_remote_submodule(update_data->sm_path);
> 	const char *branch = remote_submodule_branch(update_data->sm_path);
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  builtin/submodule--helper.c | 58 +++++++++++++++++++++++--------------
>  1 file changed, 37 insertions(+), 21 deletions(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 88fc01320f3..9e4069b36cb 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -31,48 +31,57 @@
>  typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
>  				  void *cb_data);
>  
> -static char *repo_get_default_remote(struct repository *repo)
> +static int repo_get_default_remote(struct repository *repo, char **default_remote)
>  {
> -	char *dest = NULL, *ret;
> +	char *dest = NULL;
>  	struct strbuf sb = STRBUF_INIT;
>  	struct ref_store *store = get_main_ref_store(repo);
>  	const char *refname = refs_resolve_ref_unsafe(store, "HEAD", 0, NULL,
>  						      NULL);
>  
>  	if (!refname)
> -		die(_("No such ref: %s"), "HEAD");
> +		return die_message(_("No such ref: %s"), "HEAD");
>  
>  	/* detached HEAD */
> -	if (!strcmp(refname, "HEAD"))
> -		return xstrdup("origin");
> +	if (!strcmp(refname, "HEAD")) {
> +		*default_remote = xstrdup("origin");
> +		return 0;
> +	}
>  
>  	if (!skip_prefix(refname, "refs/heads/", &refname))
> -		die(_("Expecting a full ref name, got %s"), refname);
> +		return die_message(_("Expecting a full ref name, got %s"),
> +				   refname);
>  
>  	strbuf_addf(&sb, "branch.%s.remote", refname);
>  	if (repo_config_get_string(repo, sb.buf, &dest))
> -		ret = xstrdup("origin");
> +		*default_remote = xstrdup("origin");
>  	else
> -		ret = dest;
> +		*default_remote = dest;
>  
>  	strbuf_release(&sb);
> -	return ret;
> +	return 0;
>  }

>  
> -static char *get_default_remote_submodule(const char *module_path)
> +static int get_default_remote_submodule(const char *module_path, char **default_remote)
>  {
>  	struct repository subrepo;
>  
>  	if (repo_submodule_init(&subrepo, the_repository, module_path,
>  				null_oid()) < 0)
> -		die(_("could not get a repository handle for submodule '%s'"),
> -		    module_path);
> -	return repo_get_default_remote(&subrepo);
> +		return die_message(_("could not get a repository handle for submodule '%s'"),
> +				   module_path);
> +	return repo_get_default_remote(&subrepo, default_remote);
>  }
>  
>  static char *get_default_remote(void)
>  {
> -	return repo_get_default_remote(the_repository);
> +	char *default_remote;
> +	int code = repo_get_default_remote(the_repository, &default_remote);
> +
> +	if (code)
> +		exit(code);
> +
> +	return default_remote;
>  }

> @@ -1159,6 +1168,7 @@ static void sync_submodule(const char *path, const char *prefix,
>  	char *sub_origin_url, *super_config_url, *displaypath, *default_remote;
>  	struct strbuf sb = STRBUF_INIT;
>  	char *sub_config_path = NULL;
> +	int code;
>  
>  	if (!is_submodule_active(the_repository, path))
>  		return;
> @@ -1198,10 +1208,9 @@ static void sync_submodule(const char *path, const char *prefix,
>  		goto cleanup;
>  
>  	strbuf_reset(&sb);
> -	default_remote = get_default_remote_submodule(path);
> -	if (!default_remote)
> -		die(_("failed to get the default remote for submodule '%s'"),
> -		      path);
> +	code = get_default_remote_submodule(path, &default_remote);
> +	if (code)
> +		exit(code);