Re: Wrong unsafe-flag test in check_output_expressions()

On Wed, Jun 3, 2026 at 5:59 AM David Rowley <dgrowleyml@gmail.com> wrote:
> On Mon, 1 Jun 2026 at 20:27, Richard Guo <guofenglinux@gmail.com> wrote:
> > I happened to notice $subject when working on a bug-fix near-by.
> >
> >    /* If subquery uses window functions, check point 4 */
> >    if (subquery->hasWindowFuncs &&
> >        (safetyInfo->unsafeFlags[tle->resno] &
> >         UNSAFE_NOTIN_DISTINCTON_CLAUSE) == 0 &&
> >        !targetIsInAllPartitionLists(tle, subquery))
> >    {
> >        /* not present in all PARTITION BY clauses, so mark it unsafe */
> >        safetyInfo->unsafeFlags[tle->resno] |= UNSAFE_NOTIN_PARTITIONBY_CLAUSE;
> >        continue;
> >    }

> Yes, that's not intentional. Your proposed fix looks correct. Are you
> happy to go ahead with pushing and backpatching that?

Thanks for taking a look.  Yeah, I'm happy to push that.  I'm kind of
unsure whether this needs to be back-patched, since it doesn't lead to
wrong plans, so it isn't a live bug in practice.

> Wondering, did you spot that with eyes or tool assist?

For this one, I spotted it with eyeballs, when I was working on
another patch that fixes qual pushdown past window functions (and
other grouping layers) with mismatched opfamily/collation.

- Richard