Re: [PATCH 1/2] pretty: add %(describe)

From: René Scharfe. <l.s.r@web.de>
Date: Feb 16, 2021, 17:13 UTC
Message-ID: <66720982-04d6-3096-9ea2-ea5bc3fcd121@web.de>
In-Reply-To: <87pn109nhr.fsf@evledraar.gmail.com>

Am 16.02.21 um 14:00 schrieb Ævar Arnfjörð Bjarmason:

Show 15 quoted lines

>
> On Sun, Feb 14 2021, René Scharfe wrote:
>
>> Add a format placeholder for describe output.  Implement it by actually
>> calling git describe, which is simple and guarantees correctness.  It's
>> intended to be used with $Format:...$ in files with the attribute
>> export-subst and git archive.
>
> Does it really guarantee correctness though? In "builtin/describe.c" we
> first walk over the refs and use that to format all N items we're asked
> about.
>
> Under "git log" this is presumably in a race where refs added/deleted
> during the run of "git log" will change the describe output to be
> inconsistent with earlier lines.

Right, didn't think of that aspect. So we'd better warn about the raciness in the documentation.

We could improve that by keeping a single describe process around and feeding it object names through a pipe as we go. The results would still become outdated after a ref is added or removed, but they'd be consistent. This would be faster as well.

René