Re: BUG #18845: DEREF_OF_NULL.RET guc_malloc possibly returns NULL

> On 14 Mar 2025, at 15:04, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Daniel Gustafsson <daniel(at)yesql(dot)se> writes:
>> Why would we want FATAL here? Wouldn't it be better to return false like how
>> other check_ functions already do?
>
> Indeed. Also, a quick survey shows a lot of inconsistency in
> guc_malloc callers --- some are lazy and just use ERROR rather
> than LOG-and-return. That's probably all right for PGC_POSTMASTER
> variables (since there's no chance of continuing anyway) but
> perhaps it's worth improving elsewhere.

Turns out there was one more guc_malloc(LOG.. which didn't inspect the
returned allocation in check_synchronized_standby_slots. On top of that there
were a few non PGC_POSTMASTER check functions that could return false and let
the GUC machinery handle it if we want to be consistent.

The fix for check_createrole_self_grant should go down to v16 and the fix for
check_synchronized_standby_slots down to 17, the other ones aren't bugs today
so that would be a changed behaviour in backbranches.

--
Daniel Gustafsson