Re: perl: unsafe empty pattern behavior

On Tue, 2024-03-12 at 18:53 +0100, Alvaro Herrera wrote:
> I suggest that pg_dump/t/002_pg_dump.pl could use a verification that
> the ->{regexp} thing is not empty.

I'm not sure how exactly to test for an empty pattern. The problem is,
we don't really want to test for an empty pattern, because /(?^:)/ is
fine. The problem is //, which gets turned into an actual pattern
(perhaps empty or perhaps not), and by the time it's in the %tests
hash, I think it's too late to distinguish.

Again, I'm not a perl expert, so suggestions welcome.

>   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.

Grepping for regexes in perl code is an "interesting" exercise.

Regards,
Jeff Davis