bug#81396: 30.2; setopt is silently ignored by defcustom with custom-initialize-changed

> Cc: [email protected]
> Date: Mon, 27 Jul 2026 20:03:38 -0400
> From: Stefan Monnier via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <[email protected]>
> 
> Lin Jian [2026-07-28 07:43:36] wrote:
> > Stefan Monnier <[email protected]> writes:
> >> Thanks, pushed to `master`, closing,
> > Can it be backported to Emacs 31?
> 
> I judged that it's too close to the release for that
> (and also because AFAIK it's not a regression in Emacs-31).
> But if Emacs maintainers think otherwise, I can push it to `emacs-31`,
> of course.

I agree with Stefan: this is one of the minefields in Emacs.

But we could consider backporting this to Emacs 31.2 if no problems
are reported until then.