Re: [PATCH] fixup! describe: stop traversing when we run out of names

From: Jeff King <peff@peff.net>
Date: Dec 4, 2024, 23:54 UTC
Message-ID: <20241204235440.GA2560861@coredump.intra.peff.net>
In-Reply-To: <20241204232750.GA1460551@coredump.intra.peff.net>

On Wed, Dec 04, 2024 at 06:27:50PM -0500, Jeff King wrote:

Show 16 quoted lines

> > -	if (!max_candidates)
> > +	if (!max_candidates && !always)
> >  		die(_("no tag exactly matches '%s'"), oid_to_hex(&cmit->object.oid));
> >  	if (debug)
> >  		fprintf(stderr, _("No exact match on refs or tags, searching to describe\n"));
> 
> Yep, this is the same spot I found. I think it's the right place to make
> the fix.
> 
> > Subject: Re: [PATCH] fixup! describe: stop traversing when we run out of names
> 
> This commit is already in 'next', so it's too late to squash in a change
> (though I'd have done this separately anyway, as it's already an issue
> for a manual --candidates=0 setting, as unlikely as that is).
> 
> Can you re-send with a full commit message?

In case it helps with writing a commit message:

I wondered why this line was there at all. It comes from 2c33f75754 (Teach git-describe --exact-match to avoid expensive tag searches, 2008-02-24). The --exact-match option is implemented by setting max-candidates to 0. So:

  git describe --exact-match --always

has always been broken, but probably nobody ever cared. My series reduces the max_candidates setting automatically when there is nothing to find, which means you are more likely to hit the bug.

-Peff