Merge branch 'zh/push-to-delete-onelevel-ref'

"git push" has been taught to allow deletion of refs with one-level
names to help repairing a repository who acquired such a ref by
mistake.  In general, we don't encourage use of such a ref, and
creation or update to such a ref is rejected as before.

* zh/push-to-delete-onelevel-ref:
  push: allow delete single-level ref
  receive-pack: fix funny ref error messsage

builtin/receive-pack.c

@@ -1460,8 +1460,10 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		find_shared_symref(worktrees, "HEAD", name);
 
 	/* only refs/... are allowed */
-	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
-		rp_error("refusing to create funny ref '%s' remotely", name);
+	if (!starts_with(name, "refs/") ||
+	    check_refname_format(name + 5, is_null_oid(new_oid) ?
+				 REFNAME_ALLOW_ONELEVEL : 0)) {
+		rp_error("refusing to update funny ref '%s' remotely", name);
 		ret = "funny refname";
 		goto out;
 	}

connect.c

@@ -31,7 +31,8 @@ static int check_ref(const char *name, unsigned int flags)
 		return 0;
 
 	/* REF_NORMAL means that we don't want the magic fake tag refs */
-	if ((flags & REF_NORMAL) && check_refname_format(name, 0))
+	if ((flags & REF_NORMAL) && check_refname_format(name,
+							 REFNAME_ALLOW_ONELEVEL))
 		return 0;
 
 	/* REF_HEADS means that we want regular branch heads */

t/t5516-fetch-push.sh

@@ -401,6 +401,11 @@ test_expect_success 'push with ambiguity' '
 
 '
 
+test_expect_success 'push with onelevel ref' '
+	mk_test testrepo heads/main &&
+	test_must_fail git push testrepo HEAD:refs/onelevel
+'
+
 test_expect_success 'push with colon-less refspec (1)' '
 
 	mk_test testrepo heads/frotz tags/frotz &&
@@ -898,6 +903,13 @@ test_expect_success 'push --delete refuses empty string' '
 	test_must_fail git push testrepo --delete ""
 '
 
+test_expect_success 'push --delete onelevel refspecs' '
+	mk_test testrepo heads/main &&
+	git -C testrepo update-ref refs/onelevel refs/heads/main &&
+	git push testrepo --delete refs/onelevel &&
+	test_must_fail git -C testrepo rev-parse --verify refs/onelevel
+'
+
 test_expect_success 'warn on push to HEAD of non-bare repository' '
 	mk_test testrepo heads/main &&
 	(