refs.c: change resolve_ref_unsafe reading argument to be a flags field

resolve_ref_unsafe takes a boolean argument for reading (a nonexistent ref
resolves successfully for writing but not for reading).  Change this to be
a flags field instead, and pass the new constant RESOLVE_REF_READING when
we want this behaviour.

While at it, swap two of the arguments in the function to put output
arguments at the end.  As a nice side effect, this ensures that we can
catch callers that were unaware of the new API so they can be audited.

Give the wrapper functions resolve_refdup and read_ref_full the same
treatment for consistency.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

15 files changed, 32 insertions, 24 deletions

diff --git a/builtin/blame.c b/builtin/blame.c
index 3838be2b02..303e217ae9 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -2286,7 +2286,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	commit->date = now;
 	parent_tail = &commit->parents;
 
-	if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
+	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
 		die("no such ref: HEAD");
 
 	parent_tail = append_parent(parent_tail, head_sha1);
diff --git a/builtin/branch.c b/builtin/branch.c
index 67850975e7..6491bacd69 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -131,7 +131,8 @@ static int branch_merged(int kind, const char *name,
 		    branch->merge[0] &&
 		    branch->merge[0]->dst &&
 		    (reference_name = reference_name_to_free =
-		     resolve_refdup(branch->merge[0]->dst, sha1, 1, NULL)) != NULL)
+		     resolve_refdup(branch->merge[0]->dst, RESOLVE_REF_READING,
+				    sha1, NULL)) != NULL)
 			reference_rev = lookup_commit_reference(sha1);
 	}
 	if (!reference_rev)
@@ -235,7 +236,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		free(name);
 
 		name = mkpathdup(fmt, bname.buf);
-		target = resolve_ref_unsafe(name, sha1, 0, &flags);
+		target = resolve_ref_unsafe(name, 0, sha1, &flags);
 		if (!target ||
 		    (!(flags & REF_ISSYMREF) && is_null_sha1(sha1))) {
 			error(remote_branch
@@ -299,7 +300,7 @@ static char *resolve_symref(const char *src, const char *prefix)
 	int flag;
 	const char *dst;
 
-	dst = resolve_ref_unsafe(src, sha1, 0, &flag);
+	dst = resolve_ref_unsafe(src, 0, sha1, &flag);
 	if (!(dst && (flag & REF_ISSYMREF)))
 		return NULL;
 	if (prefix)
@@ -869,7 +870,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 	track = git_branch_track;
 
-	head = resolve_refdup("HEAD", head_sha1, 0, NULL);
+	head = resolve_refdup("HEAD", 0, head_sha1, NULL);
 	if (!head)
 		die(_("Failed to resolve HEAD as a valid ref."));
 	if (!strcmp(head, "HEAD"))
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b4decd5b19..5410dacea0 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -355,7 +355,7 @@ static int checkout_paths(const struct checkout_opts *opts,
 	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 		die(_("unable to write new index file"));
 
-	read_ref_full("HEAD", rev, 0, &flag);
+	read_ref_full("HEAD", 0, rev, &flag);
 	head = lookup_commit_reference_gently(rev, 1);
 
 	errs |= post_checkout_hook(head, head, 0);
@@ -775,7 +775,7 @@ static int switch_branches(const struct checkout_opts *opts,
 	unsigned char rev[20];
 	int flag, writeout_error = 0;
 	memset(&old, 0, sizeof(old));
-	old.path = path_to_free = resolve_refdup("HEAD", rev, 0, &flag);
+	old.path = path_to_free = resolve_refdup("HEAD", 0, rev, &flag);
 	old.commit = lookup_commit_reference_gently(rev, 1);
 	if (!(flag & REF_ISSYMREF))
 		old.path = NULL;
@@ -1072,7 +1072,7 @@ static int checkout_branch(struct checkout_opts *opts,
 		unsigned char rev[20];
 		int flag;
 
-		if (!read_ref_full("HEAD", rev, 0, &flag) &&
+		if (!read_ref_full("HEAD", 0, rev, &flag) &&
 		    (flag & REF_ISSYMREF) && is_null_sha1(rev))
 			return switch_unborn_to_new_branch(opts);
 	}
diff --git a/builtin/clone.c b/builtin/clone.c
index d3bf9532d6..7f509d06a8 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -623,7 +623,7 @@ static int checkout(void)
 	if (option_no_checkout)
 		return 0;
 
-	head = resolve_refdup("HEAD", sha1, 1, NULL);
+	head = resolve_refdup("HEAD", RESOLVE_REF_READING, sha1, NULL);
 	if (!head) {
 		warning(_("remote HEAD refers to nonexistent ref, "
 			  "unable to checkout.\n"));
diff --git a/builtin/commit.c b/builtin/commit.c
index a7857ab560..aa0940e38f 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1515,7 +1515,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", junk_sha1, 0, NULL);
+	head = resolve_ref_unsafe("HEAD", 0, junk_sha1, NULL);
 	if (!strcmp(head, "HEAD"))
 		head = _("detached HEAD");
 	else
diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 79df05ef52..37177c6c29 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -602,7 +602,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
 	/* get current branch */
 	current_branch = current_branch_to_free =
-		resolve_refdup("HEAD", head_sha1, 1, NULL);
+		resolve_refdup("HEAD", RESOLVE_REF_READING, head_sha1, NULL);
 	if (!current_branch)
 		die("No current branch");
 	if (starts_with(current_branch, "refs/heads/"))
diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index fda0f04712..492265d9f9 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -635,7 +635,8 @@ static void populate_value(struct refinfo *ref)
 
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
 		unsigned char unused1[20];
-		ref->symref = resolve_refdup(ref->refname, unused1, 1, NULL);
+		ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
+					     unused1, NULL);
 		if (!ref->symref)
 			ref->symref = "";
 	}
@@ -693,7 +694,8 @@ static void populate_value(struct refinfo *ref)
 			const char *head;
 			unsigned char sha1[20];
 
-			head = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
+			head = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
+						  sha1, NULL);
 			if (!strcmp(ref->refname, head))
 				v->s = "*";
 			else
diff --git a/builtin/fsck.c b/builtin/fsck.c
index e9ba576c1f..a27515aeaa 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -556,7 +556,7 @@ static int fsck_head_link(void)
 	if (verbose)
 		fprintf(stderr, "Checking HEAD link\n");
 
-	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, 0, &flag);
+	head_points_at = resolve_ref_unsafe("HEAD", 0, head_sha1, &flag);
 	if (!head_points_at)
 		return error("Invalid HEAD");
 	if (!strcmp(head_points_at, "HEAD"))
diff --git a/builtin/log.c b/builtin/log.c
index 1202eba8b6..83c0b92707 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1400,7 +1400,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		if (check_head) {
 			unsigned char sha1[20];
 			const char *ref, *v;
-			ref = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
+			ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
+						 sha1, NULL);
 			if (ref && skip_prefix(ref, "refs/heads/", &v))
 				branch_name = xstrdup(v);
 			else
diff --git a/builtin/merge.c b/builtin/merge.c
index 4513fadc5f..bebbe5b308 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1101,7 +1101,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
 	 * current branch.
 	 */
-	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
+	branch = branch_to_free = resolve_refdup("HEAD", 0, head_sha1, &flag);
 	if (branch && starts_with(branch, "refs/heads/"))
 		branch += 11;
 	if (!branch || is_null_sha1(head_sha1))
diff --git a/builtin/notes.c b/builtin/notes.c
index 67d0bb14f8..68b6cd8cc1 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -702,7 +702,7 @@ static int merge_commit(struct notes_merge_options *o)
 	init_notes(t, "NOTES_MERGE_PARTIAL", combine_notes_overwrite, 0);
 
 	o->local_ref = local_ref_to_free =
-		resolve_refdup("NOTES_MERGE_REF", sha1, 0, NULL);
+		resolve_refdup("NOTES_MERGE_REF", 0, sha1, NULL);
 	if (!o->local_ref)
 		die("Failed to resolve NOTES_MERGE_REF");
 
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index df6c337d69..27e9dc2c5b 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -909,7 +909,7 @@ 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_unsafe(buf.buf, sha1, 0, &flag);
+	dst_name = resolve_ref_unsafe(buf.buf, 0, sha1, &flag);
 	strbuf_release(&buf);
 
 	if (!(flag & REF_ISSYMREF))
@@ -1070,7 +1070,7 @@ 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", sha1, 0, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", 0, sha1, NULL);
 
 	checked_connectivity = 1;
 	for (cmd = commands; cmd; cmd = cmd->next) {
diff --git a/builtin/remote.c b/builtin/remote.c
index 9a4640dbf0..42a533aec3 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -567,7 +567,8 @@ static int read_remote_branches(const char *refname,
 	strbuf_addf(&buf, "refs/remotes/%s/", rename->old);
 	if (starts_with(refname, buf.buf)) {
 		item = string_list_append(rename->remote_branches, xstrdup(refname));
-		symref = resolve_ref_unsafe(refname, orig_sha1, 1, &flag);
+		symref = resolve_ref_unsafe(refname, RESOLVE_REF_READING,
+					    orig_sha1, &flag);
 		if (flag & REF_ISSYMREF)
 			item->util = xstrdup(symref);
 		else
@@ -703,7 +704,7 @@ static int mv(int argc, const char **argv)
 		int flag = 0;
 		unsigned char sha1[20];
 
-		read_ref_full(item->string, sha1, 1, &flag);
+		read_ref_full(item->string, RESOLVE_REF_READING, sha1, &flag);
 		if (!(flag & REF_ISSYMREF))
 			continue;
 		if (delete_ref(item->string, NULL, REF_NODEREF))
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index 199b081e9b..270e39c6c1 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -728,7 +728,9 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		if (ac == 0) {
 			static const char *fake_av[2];
 
-			fake_av[0] = resolve_refdup("HEAD", sha1, 1, NULL);
+			fake_av[0] = resolve_refdup("HEAD",
+						    RESOLVE_REF_READING,
+						    sha1, NULL);
 			fake_av[1] = NULL;
 			av = fake_av;
 			ac = 1;
@@ -789,7 +791,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		}
 	}
 
-	head_p = resolve_ref_unsafe("HEAD", head_sha1, 1, NULL);
+	head_p = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
+				    head_sha1, NULL);
 	if (head_p) {
 		head_len = strlen(head_p);
 		memcpy(head, head_p, head_len + 1);
diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c
index b6a711d319..29fb3f1c20 100644
--- a/builtin/symbolic-ref.c
+++ b/builtin/symbolic-ref.c
@@ -13,7 +13,7 @@ static int check_symref(const char *HEAD, int quiet, int shorten, int print)
 {
 	unsigned char sha1[20];
 	int flag;
-	const char *refname = resolve_ref_unsafe(HEAD, sha1, 0, &flag);
+	const char *refname = resolve_ref_unsafe(HEAD, 0, sha1, &flag);
 
 	if (!refname)
 		die("No such ref: %s", HEAD);