From: Tom Lane <tgl@sss.pgh.pa.us>
To: Fujii Masao <masao.fujii@gmail.com>
cc: jj-zhang25@mails.tsinghua.edu.cn, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19644: byteaout,
 float8out and float4out are marked IMMUTABLE but depend on GUCs
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References: <19644-d6db3fb5e5ad92f4@postgresql.org>
 <CAHGQGwFPDZ8bMW6adGtAiEmMWQ8hTPCV_1APtoTQ38+2bXXgWA@mail.gmail.com>
Comments: In-reply-to Fujii Masao <masao.fujii@gmail.com>
	message dated "Wed, 02 Sep 2026 12:08:30 +0900"
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Date: Tue, 01 Sep 2026 23:15:59 -0400
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Fujii Masao <masao.fujii@gmail.com> writes:
> On Tue, Sep 1, 2026 at 10:12=E2=80=AFPM PG Bug reporting form
> <noreply@postgresql.org> wrote:
>> Mark byteaout, float8out and float4out (and the corresponding casts to =
text)
>> STABLE rather than IMMUTABLE, matching date_out, interval_out and cash_=
out.

> +1 to making such changes on master, even though they would cause
> several compatibility issues for existing users...

I agree with changing this on master, but I see no reason to do
anything whatever in the back branches.  There are few situations
where the mutability marking of a datatype output function matters,
and even if it does, you don't see an actual problem unless you
change one of these GUCs mid-query.  If it were a big deal,
we would have noticed this ages ago.

			regards, tom lane