Re: If a row-level security policy contains a set returning function, pg_dump returns an incorrect serialization of that policy if the return type of the function was altered

On Wed, 20 Jul 2022 at 21:54, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> This has nothing particularly to do with RLS policies; you can
> reproduce the same problem with any stored query that selects from a
> function-returning-composite, for instance a view.
>

Yep, I reached the same conclusion.

> What we have to do here is to suppress the aliases for any since-dropped
> columns, while keeping the live ones.  That's slightly finicky, but there
> is existing code that can get the job done.  ruleutils just wasn't
> considering the possibility that function RTEs might have this problem.
>

Agreed. I even came up with a similar patch, but your version looks better.

> The larger issue that this touches on is that we don't prevent you from
> dropping the composite type's column even when the query using the
> dependent function has hard references to that column (e.g, it's actually
> output by the view).  Maybe sometime somebody ought to work on tightening
> that up.  In the meantime though, it's bad for EXPLAIN or pg_dump to fail
> altogether on such cases, so I propose the behavior shown in the attached
> patch.
>

+1. LGTM.

Regards,
Dean