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Sender: Junio C Hamano <jch2355@gmail.com>
From:   Junio C Hamano <gitster@pobox.com>
To:     =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason <avarab@gmail.com>
Cc:     Lars Kellogg-Stedman <lars@oddbit.com>, git@vger.kernel.org
Subject: Re: [PATCH v2] line-range: Fix infinite loop bug with degenerate regex
References: <20221205193625.2424202-1-lars@oddbit.com>
        <221207.86tu27aju3.gmgdl@evledraar.gmail.com>
Date:   Wed, 07 Dec 2022 14:29:50 +0900
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Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

> It's perfectly OK to provide a zero-width regex in general, e.g. try:
> Or for a non-git tool:
> ...

The same story goes for "^" or even ".*", I suspect.

> I think the real bug here is that we are pointing our regexec() at the
> haystack of multiple lines as an optimization.
>
> Then in "determine extent of line matched" and "is it a funcname line"
> assuming that a positive match must be non-zero-width. But that's just
> because the optimization is leaky.

Good thinking.