From: René Scharfe <l.s.r@web.de>
Date: Fri, 19 Nov 2021 16:08:06 GMT
Subject: Re: [PATCH v13 3/3] grep/pcre2: fix an edge case concerning ascii patterns and UTF-8 data
Message-ID: <d1509690-0341-b6ef-5fd4-878ebbdfaf39@web.de>
In-Reply-To: <211119.86mtm04og8.gmgdl@evledraar.gmail.com>

Am 19.11.21 um 08:00 schrieb Ævar Arnfjörð Bjarmason:
>
> On Thu, Nov 18 2021, René Scharfe wrote:
>
>> Am 18.11.21 um 19:17 schrieb Junio C Hamano:
>>> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>> [...]
>>> I guess this is a lot of change in the amount of text involved but
>>> the least amount of actual change in the behaviour.  For those with
>>> newer PCREv2, the behaviour would be the same as v2.34.0, and for
>>> others, the behaviour would be the same as v2.33.0.
>>>
>>> Having said all that, because the consensus seems to be that the
>>> whole "when we should match in UTF mode" may need to be rethought, I
>>> think reverting Hamza's [v13 3/3] would be the simplest way to clean
>>> up the mess for v2.34.1 that will give us a cleaner slate to later
>>> build on, than applying this patch.
>>
>> Makes sense to me.  It gives a better starting point to solve the issue
>> afresh without getting entangled in mind-melting boolean expressions.
>
> Yes, agreed. As noted I haven't had time to dig deeply into this, but
> from what I've seen so far there doesn't seem to be any obvious way
> forward in terms of a quick fix.
>
> I thought perhaps your patch would be that (but I haven't looked into it
> carefully enough), but since you're on-board with reverting & retrying.

That patch should fix the edge case without any side-effects -- at least
I haven't seen any reports of ill effects that would apply to it.  It's
easier to understand and reason about when applied after reverting, I
think.  But it's only for grep.c and I don't know the situation in t/.

René