Files
Nathan Bossart 11794314f6 Allow resetting unknown custom GUCs with reserved prefixes.
Currently, ALTER DATABASE/ROLE/SYSTEM RESET [ALL] with an unknown
custom GUC with a prefix reserved by MarkGUCPrefixReserved() errors
(unless a superuser runs a RESET ALL variant).  This is problematic
for cases such as an extension library upgrade that removes a GUC.
To fix, simply make sure the relevant code paths explicitly allow
it.  Note that we require superuser or privileges on the parameter
to reset it.  This is perhaps a bit more restrictive than is
necessary, but it's not clear whether further relaxing the
requirements is safe.

Oversight in commit 2dad1eedff.  The ALTER SYSTEM fix is dependent
on commit 29dcdd6b7a, which first appeared in v17.  Unfortunately,
back-patching that commit would introduce ABI breakage, and while
that breakage seems unlikely to bother anyone, it doesn't seem
worth the risk.  Hence, the ALTER SYSTEM part of this commit is
omitted on v15 and v16.

Reported-by: Mert Alev <[email protected]>
Reviewed-by: Laurenz Albe <[email protected]>
Discussion: https://postgr.es/m/18964-ba09dea8c98fccd6%40postgresql.org
Backpatch-through: 15
2025-08-01 16:52:11 -05:00
..