Re: pg11+: pg_ls_*dir LIMIT 1: temporary files .. not closed at end-of-transaction

I wrote:
> I've just finished scanning the source code and concluding that all
> of these functions are similarly broken:
> pg_ls_dir
> pg_ls_dir_files
> pg_tablespace_databases
> pg_logdir_ls_internal
> pg_timezone_names
> pgrowlocks

BTW, another thing I noticed while looking around is that some of
the functions using SRF_RETURN_DONE() think they should clean up
memory beforehand.  This is a waste of code/cycles, as long as the
memory was properly allocated in funcctx->multi_call_memory_ctx,
because funcapi.c takes care of deleting that context.

We should probably document that *any* manual cleanup before
SRF_RETURN_DONE() is an antipattern.  If you have to have cleanup,
it needs to be done via RegisterExprContextCallback instead.

            regards, tom lane