Subject: [PATCH v2 0/2] [RFC] push: allow delete one level ref

From: "ZheNing Hu via GitGitGadget" <[email-masked]>
Date: Sat, 04 Feb 2023 16:48:15 +0000

This might be an odd request: allow git push to delete one level refs like
"ref/foo".

Some users on my side often push "refs/for/master" to the remote for code
review, but due to a user's typo, "refs/master" is pushed to the remote.

Pushing a one level ref like "refs/foo" should not have been successful, but
since my server side directly updated the ref during the proc-receive-hook
phase of git receive-pack, "refs/foo" was mistakenly left at on the server.

But for some reasons, users cannot delete this special branch through "git
push -d".

First, I executed git update-ref --stdin inside my proc-receive-hook to
delete the branch. As a result, update-ref reported an error: "cannot lock
ref 'refs/foo': reference already exists".

So I tried GIT_TRACKET_PACKET to debug and found that git push did not seem
to pass the correct ref old-oid, which is why update-ref reported an error.

"18:13:41.214872 pkt-line.c:80           packet: receive-pack< 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 refs/foo\0 report-status-v2 side-band-64k object-format=sha1 agent=git/2.39.0.227.g262c45b6a1"

Tracing it back, the check_ref() in the git push link didn't record the
old-oid for the remote "refs/foo".

At the same time, the server update() process will reject the one level ref
by default and return a "funny refname" error.

It is worth mentioning that since I deleted the branch, the error message
returned here is "refusing to create funny ref 'refs/foo' remotely", which
is also worth fixing.

So this patch series do:

v1.

 1. fix funny refname error message from "create" to "update".
 2. let server allow delete one level ref.
 3. let client pass correct one level ref old-oid.

v2.

 1. fix code style.

ZheNing Hu (2):
  receive-pack: fix funny ref error messsage
  [RFC] push: allow delete one level ref

 builtin/receive-pack.c |  6 ++++--
 connect.c              |  3 ++-
 t/t5516-fetch-push.sh  | 12 ++++++++++++
 3 files changed, 18 insertions(+), 3 deletions(-)

base-commit: a38d39a4c50d1275833aba54c4dbdfce9e2e9ca1
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1465%2Fadlternative%2Fzh%2Fdelete-one-level-ref-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1465/adlternative/zh/delete-one-level-ref-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1465

Range-diff vs v1:

 1:  214a2b662e3 = 1:  214a2b662e3 receive-pack: fix funny ref error messsage
 2:  605b95bf8ab ! 2:  966cb49c388 [RFC] push: allow delete one level ref
     @@ builtin/receive-pack.c: static const char *update(struct command *cmd, struct sh
       	/* 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) ?
     ++	    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";
     @@ connect.c: static int check_ref(const char *name, unsigned int flags)
       
       	/* 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))
     ++	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: test_expect_success 'push --delete refuses empty string'
       
      +test_expect_success 'push --delete onelevel refspecs' '
      +	mk_test testrepo heads/main &&
     -+	(
     -+		cd testrepo &&
     -+		git update-ref refs/onelevel refs/heads/main
     -+	) &&
     ++	git -C testrepo 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_must_fail git -C testrepo rev-parse --verify refs/onelevel
      +'
      +
       test_expect_success 'warn on push to HEAD of non-bare repository' '

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