Re: Yet more ROLE changes in v18 beta1???

On Wed, 2025-06-04 at 18:42 +0200, Dominique Devienne wrote:
> On Wed, Jun 4, 2025 at 5:34 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Dominique Devienne <ddevienne(at)gmail(dot)com> writes:
> > > In any case, if anyone else knows about changes in this area, I'm interested.
> >
> > Digging through the commit log didn't find much, but conceivably
> >
> > https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=01463e1cc
> > Ensure that AFTER triggers run as the instigating user.
>
> Thanks Tom. We don't drop ROLEs in trigger (yet, we'll get there).
> So that particular commit is probably not the reason.
> Thanks a bunch for looking into it. --DD

That change is not about dropping roles, but:

- before, if you had a deferred constraint trigger that was triggered while
you temporarily assumed a different role (e.g., the DML statement is executed
in a SECURITY DEFINER function), the trigger was executed as the current user
at commit time

- from v18 on, the trigger gets executed as the user that ran the DML statement

I would be somewhat surprised if you hit this rather exotic case that went
unnoticed for many years, but it is possible.
Do you have deferred constraint triggers?

Yours,
Laurenz Albe