refs: pass NULL to resolve_refdup() if hash is not needed

This allows us to get rid of several write-only variables.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/checkout.c

@@ -1116,9 +1116,8 @@ static int checkout_branch(struct checkout_opts *opts,
 
 	if (new->path && !opts->force_detach && !opts->new_branch &&
 	    !opts->ignore_other_worktrees) {
-		struct object_id oid;
 		int flag;
-		char *head_ref = resolve_refdup("HEAD", 0, oid.hash, &flag);
+		char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
 		if (head_ref &&
 		    (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
 			die_if_checked_out(new->path, 1);

builtin/receive-pack.c

@@ -1458,7 +1458,6 @@ static void execute_commands(struct command *commands,
 {
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	struct command *cmd;
-	struct object_id oid;
 	struct iterate_data data;
 	struct async muxer;
 	int err_fd = 0;
@@ -1515,7 +1514,7 @@ static void execute_commands(struct command *commands,
 	check_aliased_updates(commands);
 
 	free(head_name_to_free);
-	head_name = head_name_to_free = resolve_refdup("HEAD", 0, oid.hash, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", 0, NULL, NULL);
 
 	if (use_atomic)
 		execute_commands_atomic(commands, si);

ref-filter.c

@@ -295,9 +295,7 @@ static void if_atom_parser(const struct ref_format *format, struct used_atom *at
 
 static void head_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
 {
-	struct object_id unused;
-
-	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, unused.hash, NULL);
+	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
 }
 
 static struct {
@@ -1317,9 +1315,8 @@ static void populate_value(struct ref_array_item *ref)
 	ref->value = xcalloc(used_atom_cnt, sizeof(struct atom_value));
 
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
-		struct object_id unused1;
 		ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
-					     unused1.hash, NULL);
+					     NULL, NULL);
 		if (!ref->symref)
 			ref->symref = "";
 	}

reflog-walk.c

@@ -61,11 +61,10 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 	reflogs->ref = xstrdup(ref);
 	for_each_reflog_ent(ref, read_one_reflog, reflogs);
 	if (reflogs->nr == 0) {
-		struct object_id oid;
 		const char *name;
 		void *name_to_free;
 		name = name_to_free = resolve_refdup(ref, RESOLVE_REF_READING,
-						     oid.hash, NULL);
+						     NULL, NULL);
 		if (name) {
 			for_each_reflog_ent(name, read_one_reflog, reflogs);
 			free(name_to_free);
@@ -151,9 +150,8 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 		reflogs = item->util;
 	else {
 		if (*branch == '\0') {
-			struct object_id oid;
 			free(branch);
-			branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
+			branch = resolve_refdup("HEAD", 0, NULL, NULL);
 			if (!branch)
 				die ("No current branch");
 

transport.c

@@ -471,11 +471,10 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 {
 	struct ref *ref;
 	int n = 0;
-	struct object_id head_oid;
 	char *head;
 	int summary_width = transport_summary_width(refs);
 
-	head = resolve_refdup("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL);
+	head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
 
 	if (verbose) {
 		for (ref = refs; ref; ref = ref->next)

wt-status.c

@@ -121,15 +121,13 @@ static void status_printf_more(struct wt_status *s, const char *color,
 
 void wt_status_prepare(struct wt_status *s)
 {
-	struct object_id oid;
-
 	memset(s, 0, sizeof(*s));
 	memcpy(s->color_palette, default_wt_status_colors,
 	       sizeof(default_wt_status_colors));
 	s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 	s->use_color = -1;
 	s->relative_paths = 1;
-	s->branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
+	s->branch = resolve_refdup("HEAD", 0, NULL, NULL);
 	s->reference = "HEAD";
 	s->fp = stdout;
 	s->index_file = get_index_file();