bug#32257: 26.1; read-multiple-choice inf loops on mouse clicks

[Eli Zaretskii <eliz@gnu.org>]

> From: Noam Postavsky <npostavs@gmail.com>
> Cc: Andy Moreton <andrewjmoreton@gmail.com>,  32257@debbugs.gnu.org
> Date: Fri, 27 Jul 2018 08:45:03 -0400
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Andy Moreton <andrewjmoreton@gmail.com>
> >> Date: Fri, 27 Jul 2018 12:35:27 +0100
> >> 
> >> > If we want this change on emacs-26, we should carefully audit all the
> >> > other users of rmc.el
> 
> What should we check for though?

Anything that read-event handles differently from read-char.  Maybe a
good starting point is to compile a list of the differences in
behavior between the two.

> >> read-multiple choice only has two callers (`nsm-query-user' and
> >> `message-fix-before-sending') in both master and emacs-26.
> >
> > In Emacs, yes.  But what about the world out there?
> 
> I expect all the callers out in the world will exhibit the same bug.

What about the features they expect?

> At any rate, I don't see a way of fixing it in the caller, short of
> temporarily fsetting read-char into read-event.

If there's no better idea, we could copy read-multiple-choice into
nsm.el and replace read-char with read-event there.  But maybe there
are more elegant ideas.

> Also, read-multiple-choice is new in Emacs 26, so it seems to me we
> should rather fix it in 26.2.

I agree, I just am not convince that replacing read-char with
read-event is the right fix.