Re: [PATCH] t: avoid alternation (not POSIX) in grep's BRE

From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: "Carlo Marcelo Arenas Belón" <carenas@gmail.com>,
	git@vger.kernel.org, hji@dyntopia.com
Subject: Re: [PATCH] t: avoid alternation (not POSIX) in grep's BRE
Date: Thu, 28 May 2020 12:20:49 -0700	[thread overview]
Message-ID: <xmqqsgfj3lym.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200528165245.GA1223396@coredump.intra.peff.net> (Jeff King's message of "Thu, 28 May 2020 12:52:45 -0400")

Jeff King <peff@peff.net> writes:

> But I haven't really found a use for "Fixes" in machine-readable format.
> I don't _mind_ people doing it if they do have a use (and I'd even
> consider doing it myself if I were shown that it was useful). In the
> meantime, I don't know if we want to state a project preference against
> it.

I've seen "Fixes: bug number" in projects that maintain bug
databases and automatically updates the status of the named bug when
a commit with such a footer hits certain integration branches; the
utility of such a usecase would be fairly obvious.

But "Fixes: <commit>" makes me nervous.  One reason is because a
commit very often introduces multiple bugs (or no bugs at all), so
which one (or more) of the bug is corrected cannot be read from such
a footer that _only_ blames a particular commit.

	Side note: also "fixes:" footer would cast a claim made when
	a commit was created in stone---which may later turn out to
	be false.  But the issue is not unique to "Fixes: <commit>";
	"Fixes: <bugid>" suffers exactly from the same problem.

An interesting aspect of "Fixes: <commit>" is that we can use it to
easily see who is the buggiest by dividing number of buggy commit by
number of total commits per author ;-)

I'd rather not to see people adding random footers whose utility is
dubious, but for this particular one, I am not against it strongly
enough to be tempted to declare an immediate ban.