bug#25875: 26.0.50; Hang logging out of MS-Windows

[Ken Brown]

On 2/27/2017 2:56 PM, Richard Copley wrote:
> On 27 February 2017 at 19:46, Richard Copley <rcopley@gmail.com> wrote:
> > On 27 February 2017 at 19:39, Ken Brown <kbrown@cornell.edu> wrote:
> > > On 2/27/2017 2:30 PM, Richard Copley wrote:
> > > > If you want to block or delay a shutdown in recent
> > > > Windows versions you need to use
> > > > ShutdownBlockReasonCreate (it's unfortunate, but
> > > > we lazy programmers proved we couldn't be trusted,
> > > > collectively, to handle WM_QUERY_ENDSESSION
> > > > correctly, so the arms race had to be escalated in
> > > > order to allow users to shut down their computers
> > > > reliably).
> > >
> > >
> > > In spite of the careless mistake in my patch, you could still test Eli's
> > > suggestion of using SendMessageTimeout instead of SendMessage, at least in
> > > my_show_window.
> >
> > I can't, not really. Remember, I don't have a recipe.
> > I'll never be able to observe whether it's working or not.
> > (Am I missing something?)
> >
> > > > Ken, what was the original change intended to guard
> > > > against? What would people be doing with Emacs that
> > > > can't simply be abandoned? Did you have a particular
> > > > example in mind?
> > >
> > >
> > > Bug#23483.
> >
> > That's not a real issue, in my opinion. It's already covered,
> > by autosave.

No, it isn't covered.  We don't know that the auto-save files are 
up-to-date at the time of shutdown.

> There are programs like the OP in #23483 described, which
> interrupt a shutdown to ask the user whether to save. Some of
> them even call themselves "programmers' text editors" (shudder).
> Emacs autosave is and always has been a better solution.

> You can shoot yourself in the foot by making small but important
> changes and then immediately shutting down Windows. But you'd
> almost have to be doing it on purpose.

I think it's reasonable for Emacs to attempt an orderly shutdown when 
the system is being shutdown, rather than just allowing the system to 
kill it.  You've found a bug in my implementation of this, and I'm happy 
to try to fix it.

Ken