Re: [PATCH 1/1] Warn about fast-forwarding of submodules during merge

From: Leif Middelschulte <leif.middelschulte@gmail.com>
Date: May 10, 2018, 20:30 UTC
Message-ID: <CANw0+A_T5zDUUWznYBe0m9fkSODPnfQaK1yJKPPawHTxi9+9BQ@mail.gmail.com>
In-Reply-To: <CAGZ79ka3kVHSZ9oG=NOvr0=KCHODngxJQLbKApDsFY=xNPhU=A@mail.gmail.com>

Hi Stefan,

Am 10. Mai 2018 um 20:49:39, Stefan Beller (sbeller@google.com(mailto:sbeller@google.com)) schrieb:

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> On Thu, May 10, 2018 at 11:26 AM, Leif Middelschulte
> wrote:
> > From: Leif Middelschulte
>
> Hi Leif!
>
> thanks for following up with a patch!

sure, thanks for the quick review.

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>
> > Warn the user about an automatically fast-forwarded submodule. The silent merge
> > behavior was introduced by commit 68d03e4a6e44 ("Implement automatic fast-forward
> > merge for submodules", 2010-07-07)).
> >
> > Signed-off-by: Leif Middelschulte
> > ---
> > submodule.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/submodule.c b/submodule.c
> > index 74d35b257..0198a72e6 100644
> > --- a/submodule.c
> > +++ b/submodule.c
> > @@ -1817,10 +1817,12 @@ int merge_submodule(struct object_id *result, const char *path,
> > /* Case #1: a is contained in b or vice versa */
> > if (in_merge_bases(commit_a, commit_b)) {
> > oidcpy(result, b);
> > + warning("Fast-forwarding submodule %s", path);
> > return 1;
> > }
> > if (in_merge_bases(commit_b, commit_a)) {
> > oidcpy(result, a);
> > + warning("Fast-forwarding submodule %s", path);
> > return 1;
> > }
>
> The code looks correct, however I think we can improve it.
> (Originally I was just wondering if stderr is the right output,
> which lead me to the thoughts below:)

I’ve had the same thoughts about stderr. However, I thought that using a log function named `warning` to warn the user would be the right choice. If anything, I thought, the warning function might need refactoring.

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> Looking through the code of merge-recursive.c,
> all the other merge outputs are done via 'output()'
> that is able to buffer up the output as well as handles
> the output for different verbosity settings.
>
> So I would think we should make the output() function available
> outside of merge-recursive.c. (and rename it to a be more concise
> and descriptive in the global namespace) and make use of it.

Sure, let me know what to use instead and I’ll update and resubmit the patch.

>
> Funnily we already have MERGE_WARNING in submodule.c
> which outputs information for all the other cases. I would think
> we ought to convert those to the output(), too.

Sure, but `MERGE_WARNING` prefixes all the messages with "Failed to merge submodule“.

>
> Thanks,
> Stefan

Thank you, Leif