Re: Residual cleanups for tied objects in PL/Perl

On 2026-08-16 Su 1:38 PM, Tom Lane wrote:
> The attached patch fixes a null pointer dereference case in
> hstore_plperl, and an infinite-loop case in plperl itself.
> These were left out of the recent plperl security patch because
> they are not security matters according to our current rules;
> but they are certainly bugs that ought to be fixed.
>
> The test cases I have that reach these bugs require Perl "Tie"
> modules that aren't present in common Perl installations,
> so I'm not planning on trying to construct regression test
> entries for them. But I've attached two SQL scripts that
> cause failures without the patch.

Which modules?

>
> One interesting point is that Claude Opus, which constructed
> these test cases, seemed to think that we ought to be able
> to read out the values assigned to the tied array or hash.
> But what the repaired code actually produces is SQL NULLs.
> AFAICT we are getting Perl "undef" values out of hv_iternext
> or av_fetch, so it's hard to see how we could do any better.

At first glance I'm inclined to agree with Opus.

>
> I think what is going on here is that the test functions are
> failing to install enough infrastructure for the tied object
> to produce any output, but maybe someone who knows more Perl
> than me can correct that guess.
>
>

I wonder if it's conflicting with our opcode restrictions. I'll play
around a bit with it.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com