PG Bug reporting form <noreply@postgresql.org> writes:
> in function PGTYPEStimestamp_defmt_scan there is a usage of pgtypes_alloc().
> In other functions the result of pgtypes_alloc is being checked for NULL.
Thanks for the report!  It looks like this was already dealt with
during the v17 cycle:
Author: Michael Paquier <michael@paquier.xyz>
Branch: master Release: REL_17_BR [0a9118ccc] 2024-02-19 09:05:51 +0900
    ecpg: Fix error handling on OOMs when parsing timestamps
    pgtypes_alloc() can return NULL when failing an allocation, which is
    something that PGTYPEStimestamp_defmt_asc() has forgotten about when
    translating a timestamp for 'D', 'r', 'R' and 'T' as these require a
    temporary allocation.
    This is unlikely going to be a problem in practice, so no backpatch is
    done.
    Author: Oleg Tselebrovskiy
    Discussion: https://postgr.es/m/bf47888585149f83b276861a1662f7e4@postgrespro.ru
I tend to agree with Michael's conclusion that an error here is
improbable enough to not justify a back-patch.
            regards, tom lane