Re: [PATCH 2/4] refs: trim newline from reflog message - Han-Wen Nienhuys

From: Han-Wen Nienhuys <hanwen@google.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Han-Wen Nienhuys via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, Han-Wen Nienhuys <hanwenn@gmail.com>
Subject: Re: [PATCH 2/4] refs: trim newline from reflog message
Date: Wed, 24 Nov 2021 12:17:04 +0100	[thread overview]
Message-ID: <CAFQ2z_Mb+NzQfXfMhdQoPs09p2j1AWRAdXcX3JSznn+H9+T0Bw@mail.gmail.com> (raw)
In-Reply-To: <xmqqzgpu7grv.fsf@gitster.g>

On Tue, Nov 23, 2021 at 9:34 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> Han-Wen Nienhuys <hanwen@google.com> writes:
>
> > I'm talking about refs/refs-internal.h. It seems you want to add something like
> >
> > /* The ref backend should add a '\n' relative to the message supplied
> > to the delete/symref/update functions. */
> > typedef int for_each_reflog_ent_fn(struct ref_store *ref_store,
> >                                    const char *refname,
> >                                    each_reflog_ent_fn fn,
> >                                    void *cb_data);
> >
> > ?
>
> Sorry, I do not follow.  Doesn't the ref backend already ensure that
> the message is not an incomplete line?  If you feed a single
> complete line when updating, I do not think the backend should add
> any extra LF relative to the given message:

But it does, currently. As of

  commit 523fa69c36744ae6779e38614cb9bfb2be552923
  Author: Junio C Hamano <gitster@pobox.com>
  ..
  - We expect that a reflog message consists of a single line.  The
       file format used by the files backend may add a LF after the

it is the job of the files ref backend to add a LF, and the input to
the ref backend is a string without trailing LF. But the files backend
then produces that message with a LF, when reading back the data, eg.

$ git --version
git version 2.34.0.rc2.393.gf8c9666880-goog

$ GIT_TRACE_REFS="1" git branch -m bla blub
..
12:03:59.408705 refs/debug.c:162        rename_ref: refs/heads/bla ->
refs/heads/blub "Branch: renamed refs/heads/bla to refs/heads/blub": 0

$ GIT_TRACE_REFS=1 git reflog show refs/heads/blub
12:04:23.277805 refs/debug.c:294        reflog_ent refs/heads/blub
(ret 0): cd3e606211bb1cf8bc57f7d76bab98cc17a150bc ->
cd3e606211bb1cf8bc57f7d76bab98cc17a150bc, Han-Wen Nienhuys
<hanwen@google.com> 1637751839 "Branch: renamed refs/heads/bla to
refs/heads/blub
"

> I think the rule for "msg" is that:
>
>    a multi-line message, or a message on a single incomplete-line,
>    are normalized into a single complete line, and callback gets a
>    single complete line.
>

That is not how it works today. The files backend verbatimly dumps the
message supplied to it. (Maybe it should crash if there is a '\n' in
the message).

-- 
Han-Wen Nienhuys - Google Munich
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