From: Jeff King <peff@peff•net>
To: Patrick Steinhardt <ps@pks•im>
Cc: "René Scharfe" <l.s.r@web•de>,
phillip.wood@dunelm•org.uk, Cheng <prophecheng@stu•pku.edu.cn>,
git@vger•kernel.org
Subject: Re: [PATCH 4/5] describe: handle blob traversal with no commits
Date: Tue, 19 Aug 2025 12:59:47 -0400 [thread overview]
Message-ID: <20250819165947.GA1050577@coredump.intra.peff.net> (raw)
In-Reply-To: <aKQwP01nulsquhzi@pks.im>
On Tue, Aug 19, 2025 at 10:05:19AM +0200, Patrick Steinhardt wrote:
> > I didn't include a test here because it requires corrupting the
> > repository in a way that is only easy to do using the files ref backend.
> > It doesn't seem worth carrying a REFFILES test just for this oddity.
>
> True:
>
> $ git update-ref HEAD HEAD^{tree}
> fatal: update_ref failed for ref 'HEAD': trying to write non-commit object 4b825dc642cb6eb9a060e54bf8d69288fbee4904 to branch 'HEAD'
>
> But:
>
> $ git update-ref refs/some/tree HEAD^{tree}
> $ git symbolic-ref HEAD refs/some/tree
> $ git show
> tree HEAD
>
> So that should allow you to write a test, right?
Hrm, that seems like a bug. I thought we insisted that HEAD point at
refs/heads.
Ah, no. We did that in b229d18a80 (validate_headref: tighten
ref-matching to just branches, 2009-01-29), but had to revert it in
e9cc02f0e4 (symbolic-ref: allow refs/<whatever> in HEAD, 2009-02-13) to
keep compatibility for topgit. :(
Still, I'm not sure it's something I'd want to base a test on. Maybe if
there is a big comment that says "It is OK to invalidate and remove this
test if we ever tighten symbolic-ref" it would be OK?
-Peff
next prev parent reply other threads:[~2025-08-19 16:59 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-13 0:23 Potential Null Pointer Dereference detected by static analysis tool Cheng
2025-08-13 13:19 ` Phillip Wood
2025-08-14 23:26 ` Jeff King
2025-08-15 15:49 ` Phillip Wood
2025-08-17 9:27 ` René Scharfe
2025-08-18 4:48 ` Jeff King
2025-08-18 5:05 ` Jeff King
2025-08-18 19:56 ` René Scharfe
2025-08-18 20:21 ` Jeff King
2025-08-18 20:56 ` Jeff King
2025-08-18 20:58 ` [PATCH 0/5] fix segfault and other oddities describing blobs Jeff King
2025-08-18 20:59 ` [PATCH 1/5] describe: pass oid struct by const pointer Jeff King
2025-08-18 21:05 ` Junio C Hamano
2025-08-18 21:01 ` [PATCH 2/5] describe: error if blob not found Jeff King
2025-08-18 21:12 ` Junio C Hamano
2025-08-19 8:05 ` Patrick Steinhardt
2025-08-19 18:32 ` René Scharfe
2025-08-18 21:01 ` [PATCH 3/5] describe: catch unborn branch in describe_blob() Jeff King
2025-08-18 21:19 ` Junio C Hamano
2025-08-18 23:07 ` Jeff King
2025-08-18 21:03 ` [PATCH 4/5] describe: handle blob traversal with no commits Jeff King
2025-08-19 8:05 ` Patrick Steinhardt
2025-08-19 16:59 ` Jeff King [this message]
2025-08-20 4:34 ` Patrick Steinhardt
2025-08-20 6:30 ` [replacement PATCH " Jeff King
2025-08-18 21:04 ` [PATCH 5/5] describe: pass commit to describe_commit() Jeff King
2025-08-19 8:05 ` Patrick Steinhardt
2025-08-19 17:02 ` Jeff King
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