Re: BUG #19644: byteaout, float8out and float4out are marked IMMUTABLE but depend on GUCs

On Sat, Sep 5, 2026 at 2:27 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> It's been wrong for so long that I'm not that rushed to fix it in 19.
> We might find that there are consequences to be dealt with, so better
> to let the fix settle in master.

Sounds reasonable.

> > On further review, point_out, ISTM that lseg_out, path_out, box_out, poly_out,
> > circle_out, and line_out are marked IMMUTABLE but depend on extra_float_digits.
> > Similarly, pg_mcv_list_out is marked IMMUTABLE but depends on bytea_output.
> > Perhaps we should fix these at the same time...
>
> Agreed.

Attached patch marks those GUC-dependent type output functions as STABLE.

In addition to the functions I mentioned upthread, I found that
brin_minmax_multi_summary_out calls the summarized type's output
function, so its result can depend on the GUCs. The patch marks that
function STABLE as well.

Regards,

--
Fujii Masao