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

[Noam Postavsky]

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?

>> > (and in generally, I'd prefer some more local
>> > change in nsm.el on the release branch).  We've had our share of
>> > subtle bugs introduced by switching to an "almost-compatible" method
>> > of reading input.
>> 
>> 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.

> In case it wasn't clear I meant to make a safer change on emacs-26,
> and change read-multiple-choice on master.

At any rate, I don't see a way of fixing it in the caller, short of
temporarily fsetting read-char into read-event.  Also,
read-multiple-choice is new in Emacs 26, so it seems to me we should
rather fix it in 26.2.