From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeff Davis <pgsql@j-davis.com>
cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, pgsql-hackers@postgresql.org
Subject: Re: perl: unsafe empty pattern behavior
In-reply-to: <2385813054ce4e4b3e5998600da2ce95b9509dc7.camel@j-davis.com>
References: <202403121753.lw7u5b5fjsjw@alvherre.pgsql> <2385813054ce4e4b3e5998600da2ce95b9509dc7.camel@j-davis.com>
Comments: In-reply-to Jeff Davis <pgsql@j-davis.com>
	message dated "Tue, 12 Mar 2024 15:51:09 -0700"
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Date: Tue, 12 Mar 2024 18:59:04 -0400
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Jeff Davis <pgsql@j-davis.com> writes:
> On Tue, 2024-03-12 at 18:53 +0100, Alvaro Herrera wrote:
>> I also tried grepping (for things
>> like qr{}, qr[], qr||, qr!!) and didn't find anything beyond what you
>> have ... but I only looked for the "qr" literal, not other ways to
>> get regexes.

> I think that's fine. qr// seems the most dangerous, because it seems to
> behave differently in different versions of perl.

I wonder whether perlcritic has sufficiently deep understanding of
Perl code that it could find these hazards.  I already checked,
and found that there's no built-in filter for this (at least not
in the perlcritic version I have), but maybe we could write one?
The rules seem to be plug-in modules, so you can make your own
in principle.

			regards, tom lane