From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 29 Jul 2019 16:23:20 GMT
Subject: Re: [PATCH v2 4/8] grep: consistently use "p->fixed" in compile_regexp()
Message-ID: <xmqqlfwgvmh3.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <87zhkx5hlj.fsf@evledraar.gmail.com>

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

>> The reason we ignore the user's choice here is because you might
>> e.g. set grep.patternType=extended in your config, and you'd still want
>> grepping for a fixed "foo" to be fast.
>
> ...and more generally, for any future sanity of implementation and
> maintenance I think we should only make the promise that we support
> certain syntax & semantics, not that the -F, -G, -E, -P options are
> guaranteed to dispatch to a given codepath.
>
> Internally we should be free to switch between those, so e.g. if a
> pattern is fixed and you configure "basic" regexp, but we know your C
> library is faster for those matches with REG_EXTENDED we should just
> pass that regardless of -G or -E.

That certainly is a very sensible goal.

> I'm just saying that the presence of those bugs means we should be
> inclined to fix them / back out certain changes, not work around them
> with user-servicable knobs.

Amen.