GNU bug report logs - #23980
25.0.95; Events put in `unread-command-events' can be wrongly handled

Previous Next

Full log

View this message in rfc822 format

From: Dmitry Gutov <dgutov <at> yandex.ru>
To: Chris Feng <chris.w.feng <at> gmail.com>, Eli Zaretskii <eliz <at> gnu.org>
Cc: 23980 <at> debbugs.gnu.org
Subject: bug#23980: 25.0.95; Events put in `unread-command-events' can be wrongly handled
Date: Wed, 21 Feb 2018 12:47:20 +0200

On 2/21/18 9:40 AM, Chris Feng wrote:

> It seems to be the only use case in Emacs's source tree, but we can't
> tell how many packages do this trick in the wild nor can we predict
> that.

They only do that with one goal, though (so we are dealing with a protocol).

>> But then how come you have (t t . 45) there?
> 
> Probably shortly after (t . 45) is unread another call to `sit-for'
> happens to read it out directly from `unread-command-events', and the
> event is further unread as (cons t '(t . 45)).

More or less, this. Except we don't get this effect from two (or more) 
consecutive calls to sit-for.

What triggers it, is effectively recursive sit-for calls, when the 
second sit-for is called inside a timer, which are allowed to run inside 
the first sit-for.

> PS. Many users will stick with the pre-26 releases in the next upcoming
> years so backporting this fix does not necessarily resolve the problem
> for company-mode.  At least a workaround has to be come up with to deal
> with the situations where this fix is absent.

I've been trying to. So far, the options are:

- Advise users to lower flyspell-delay to (* 0.9 company-idle-delay). 
That actually leads to freezes, which I should file as a separate bug 
report.

- Ask people to disable flyspell-mode :)

- Use sleep-for instead of sit-for in the relevant place, forgoing the 
significant latency improvement that comes with the latter. Maybe 
predicated on Emacs version, and flyspell-mode being enabled.

So far the last option is winning, but I'd be much more content to use 
it if the Emacs 26 are not going to need it.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.