[PATCH 2/2] [RFC] push: allow delete one level ref

["ZheNing Hu via GitGitGadget" <gitgitgadget@gmail.com>]

From: ZheNing Hu <adlternative@gmail.com>

Git will reject the deletion of one level refs e,g. "refs/foo"
through "git push -d", however, some users want to be able to
clean up these branches that were created unexpectedly on the
remote.

Therefore, when updating branches on the server with
"git receive-pack", by checking whether it is a branch deletion
operation, it will determine whether to allow the update of
one level refs. This avoids creating/updating such one level
branches, but allows them to be deleted.

On the client side, "git push" also does not properly fill in
the old-oid of one level refs, which causes the server-side
"git receive-pack" to think that the ref's old-oid has changed
when deleting one level refs, this causes the push to be rejected.

So the solution is to fix the client to be able to delete
one level refs by properly filling old-oid.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>
---
 builtin/receive-pack.c |  5 ++++-
 connect.c              |  2 +-
 t/t5516-fetch-push.sh  | 13 +++++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 13ff9fae3ba..ad21877ea1b 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1463,7 +1463,10 @@ 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)) {
+	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;
diff --git a/connect.c b/connect.c
index 63e59641c0d..b841ae58e03 100644
--- a/connect.c
+++ b/connect.c
@@ -30,7 +30,7 @@ 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 */
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index f37861efc40..dec8950a392 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -903,6 +903,19 @@ 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 &&
+	(
+		cd testrepo &&
+		git update-ref refs/onelevel refs/heads/main
+	) &&
+	git push testrepo --delete refs/onelevel &&
+	(
+		cd testrepo &&
+		test_must_fail git rev-parse --verify refs/onelevel
+	)
+'
+
 test_expect_success 'warn on push to HEAD of non-bare repository' '
 	mk_test testrepo heads/main &&
 	(
-- 
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