Re: [gtk-osx-users] crash on maximize/unmaximize

[Allin Cottrell <cottrell wfu edu>]

On Fri, 12 Feb 2016, Miroslav Rajcic wrote:

> This [see report below] sounds similar to the crashes reported to me 
> by users of my app (I reported this case on this list in January) 
> where crashes happen only on El Capitan and are related to using app 
> in full screen or new split view.
>
> It seems that El Capitan version changed something internally, 
> because searching on the net finds many similar issues.

> For example Atom editor crashes:
> https://github.com/atom/atom/issues/9692
> https://github.com/atom/atom/issues/9584
>
> I know Atom is not a GTK+ app, but I believe that the crashes are related.
> The fix for these particular crashes in Atom are explained here:
> https://github.com/atom/electron/pull/3588
>
> Quote: "Since EL Capitan it is possible that the methods of delegate 
> would get called after the window has been closed."
>
> Could something like this be a case for GTK+ code too?

Thanks, this sounds very plausible; it fits the facts that I have 
observed. My first resort here will be to try to implement in 
GdkQuartzWindow.c the fix that the Atom guys came up with. That is, 
add a callback for the windowWillClose signal that detaches the 
delegate.

I'm totally unfamiliar with Objective C and Apple APIs, but from 
looking at the Atom and GdkQuartz code it seems that the callback 
should look like this:

- (void)windowWillClose:(NSNotification*)notification
{
  NSWindow *nsw = get_the_window();

  [nsw setDelegate:nil];
}

So my question is, what should the notional call "get_the_window()" 
actually look like? I see in GdkQuartzWindow.c code to get the 
relevant GdkWindow in this sort of notification context, namely

GdkWindow *window = [[self contentView] gdkWindow];

and I also see in gdkwindow-quartz.c a function

gdk_quartz_window_get_nswindow(GdkWindow *window);

I guess one could chain these, but I suspect this would be more 
roundabout than need be. Is "self" already the relevant NSWindow, by 
any chance, or is there a more direct way of getting it?

Thanks for any help.

Allin Cottrell

> ________________________________________
> From: Gtk-osx-users-list <gtk-osx-users-list-bounces gnome org> on behalf of Allin Cottrell <cottrell wfu edu>
> Sent: Friday, February 12, 2016 4:00 AM
> To: gtk-osx-users-list gnome org
> Subject: [gtk-osx-users] crash on maximize/unmaximize
>
> I've recently had a report of crashes from a user of my gtk-based
> app on El Capitan. The gtk version I'm using is 2.24.29. I'm able to
> reproduce the problem myself: it seems to happen only when you
> maximize then unmaximize a window (or maximize then use the close
> button). And it doesn't happen every time; I had a work away at
> maxing and unmaxing various windows for a few minutes before I got
> the crash.
>
> I'm attaching the Apple problem report. Not as informative as one
> would like, I know, but it does seem to show that the problem lies
> with GTK rather than in my own code. When the crash occurs I'm not
> doing anything substantive with the app, just resizing or closing
> windows. The segfault occurs in the function updateTrackingRect in
> GdkQuartzView.c.