RFC push: allow delete one level ref

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.

v3.

1. clarify in the docs why single-level refs are allowed to be deleted but not created/updated.

v4.

1. move the testing part of the first patch to the second patch.

ZheNing Hu (2):
receive-pack: fix funny ref error messsage
push: allow delete single-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: dadc8e6dacb629f46aee39bde90b6f09b73722eb
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1465%2Fadlternative%2Fzh%2Fdelete-one-level-ref-v4
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1465/adlternative/zh/delete-one-level-ref-v4
Pull-Request: https://github.com/gitgitgadget/git/pull/1465

Range-diff vs v3:

1: 857d2435caf ! 1: eef7bca63c6 receive-pack: fix funny ref error messsage

     @@ builtin/receive-pack.c: static const char *update(struct command *cmd, struct sh
       		ret = "funny refname";
       		goto out;
       	}
     -
     - ## t/t5516-fetch-push.sh ##
     -@@ t/t5516-fetch-push.sh: 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 &&

2: 4dc75f5b961 ! 2: 022818f0e9f [RFC] push: allow delete single-level ref
@@ Metadata
Author: ZheNing Hu <[email protected]>

## Commit message ##
- [RFC] push: allow delete single-level ref
+ push: allow delete single-level ref

We discourage the creation/update of single-level refs because some upper-layer applications only work in specified
@@ connect.c: static int check_ref(const char *name, unsigned int flags)
/* REF_HEADS means that we want regular branch heads */

## t/t5516-fetch-push.sh ##
+@@ t/t5516-fetch-push.sh: 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 &&
@@ t/t5516-fetch-push.sh: test_expect_success 'push --delete refuses empty string' '
test_must_fail git push testrepo --delete ""
'

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