Rename resolve_ref() to resolve_ref_unsafe()

resolve_ref() may return a pointer to a shared buffer and can be
overwritten by the next resolve_ref() calls. Callers need to
pay attention, not to keep the pointer when the next call happens.

Rename with "_unsafe" suffix to warn developers (or reviewers) before
introducing new call sites.

This patch is generated using the following command

git grep -l 'resolve_ref(' -- '*.[ch]'|xargs sed -i 's/resolve_ref(/resolve_ref_unsafe(/g'

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pclouds

branch.c

@@ -182,7 +182,7 @@ int validate_new_branchname(const char *name, struct strbuf *ref,
 		const char *head;
 		unsigned char sha1[20];
 
-		head = resolve_ref("HEAD", sha1, 0, NULL);
+		head = resolve_ref_unsafe("HEAD", sha1, 0, NULL);
 		if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 			die("Cannot force update the current branch.");
 	}

builtin/branch.c

@@ -252,7 +252,7 @@ static char *resolve_symref(const char *src, const char *prefix)
 	int flag;
 	const char *dst, *cp;
 
-	dst = resolve_ref(src, sha1, 0, &flag);
+	dst = resolve_ref_unsafe(src, sha1, 0, &flag);
 	if (!(dst && (flag & REF_ISSYMREF)))
 		return NULL;
 	if (prefix && (cp = skip_prefix(dst, prefix)))

builtin/commit.c

@@ -1304,7 +1304,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref("HEAD", junk_sha1, 0, NULL);
+	head = resolve_ref_unsafe("HEAD", junk_sha1, 0, NULL);
 	printf("[%s%s ",
 		!prefixcmp(head, "refs/heads/") ?
 			head + 11 :

builtin/fsck.c

@@ -563,7 +563,7 @@ static int fsck_head_link(void)
 	if (verbose)
 		fprintf(stderr, "Checking HEAD link\n");
 
-	head_points_at = resolve_ref("HEAD", head_sha1, 0, &flag);
+	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, 0, &flag);
 	if (!head_points_at)
 		return error("Invalid HEAD");
 	if (!strcmp(head_points_at, "HEAD"))

builtin/log.c

@@ -1040,7 +1040,7 @@ static char *find_branch_name(struct rev_info *rev)
 	if (positive < 0)
 		return NULL;
 	strbuf_addf(&buf, "refs/heads/%s", rev->cmdline.rev[positive].name);
-	branch = resolve_ref(buf.buf, branch_sha1, 1, NULL);
+	branch = resolve_ref_unsafe(buf.buf, branch_sha1, 1, NULL);
 	if (!branch ||
 	    prefixcmp(branch, "refs/heads/") ||
 	    hashcmp(rev->cmdline.rev[positive].item->sha1, branch_sha1))
@@ -1268,7 +1268,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 
 			rev.pending.objects[0].item->flags |= UNINTERESTING;
 			add_head_to_pending(&rev);
-			ref = resolve_ref("HEAD", sha1, 1, NULL);
+			ref = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
 			if (ref && !prefixcmp(ref, "refs/heads/"))
 				branch_name = xstrdup(ref + strlen("refs/heads/"));
 			else

builtin/receive-pack.c

@@ -572,7 +572,7 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
-	dst_name = resolve_ref(buf.buf, sha1, 0, &flag);
+	dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
 	strbuf_release(&buf);
 
 	if (!(flag & REF_ISSYMREF))

builtin/remote.c

@@ -573,7 +573,7 @@ static int read_remote_branches(const char *refname,
 	strbuf_addf(&buf, "refs/remotes/%s/", rename->old);
 	if (!prefixcmp(refname, buf.buf)) {
 		item = string_list_append(rename->remote_branches, xstrdup(refname));
-		symref = resolve_ref(refname, orig_sha1, 1, &flag);
+		symref = resolve_ref_unsafe(refname, orig_sha1, 1, &flag);
 		if (flag & REF_ISSYMREF)
 			item->util = xstrdup(symref);
 		else

builtin/show-branch.c

@@ -789,7 +789,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		}
 	}
 
-	head_p = resolve_ref("HEAD", head_sha1, 1, NULL);
+	head_p = resolve_ref_unsafe("HEAD", head_sha1, 1, NULL);
 	if (head_p) {
 		head_len = strlen(head_p);
 		memcpy(head, head_p, head_len + 1);

builtin/symbolic-ref.c

@@ -12,7 +12,7 @@ static void check_symref(const char *HEAD, int quiet)
 {
 	unsigned char sha1[20];
 	int flag;
-	const char *refs_heads_master = resolve_ref(HEAD, sha1, 0, &flag);
+	const char *refs_heads_master = resolve_ref_unsafe(HEAD, sha1, 0, &flag);
 
 	if (!refs_heads_master)
 		die("No such ref: %s", HEAD);

cache.h

@@ -865,7 +865,7 @@ extern int read_ref(const char *filename, unsigned char *sha1);
  *
  * errno is sometimes set on errors, but not always.
  */
-extern const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag);
+extern const char *resolve_ref_unsafe(const char *ref, unsigned char *sha1, int reading, int *flag);
 extern char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag);
 
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);