bug#63589: [PATCH] 29.0.91; crash after creating graphical frames via emacsclient when compiled with cairo-xcb

[Thiago Melo <tmdmelo@gmail.com>]

> > > What is the kind of situations in which these crashes could happen?
> >
> > Precisely that described in this bug report: when displays are closed
> > and reopened within a short time period.
>
> What kind of user-level situations could cause this?  Is invoking
> emacsclient soon after deleting the last visible frame the only one?
> And what does "short time period" mean, quantitatively? milliseconds?
> seconds? minutes?

Sorry, in my experience it seems that the time interval between
closing the display and opening it again doesn't matter. It seems to
be more about the amount of times that the display is closed and then
opened (which is often 3 times for me, for whatever reason).

I'm testing it here again with Xvfb and an automation script, with a
10 minutes delay after creating a single graphical frame, and another
10 minutes delay after closing it and before creating a new one. I'll
report the results soon.

Also, this bug seems more likely to happen when emacs is built without
a toolkit (which is was I've been testing so far), since the display
is always closed after the last graphical frame is closed. Which made
me realize, after looking at frame.c, that this bug might as well join
the family of Bug#5802, Bug#21509, Bug#23499, and Bug#27816.