bug#3145: 23.0.92; detaching GTK+ tool bar crashes emacs --daemon

[Jan Djärv]

Sorry, no workaround is possible.
The part in Gtk+ that handles detaching uses a hidden window which it stores 
in a static variable.  So it get created on the first display, but is still 
used on the second, but that is not a valid window anymore:

static GtkWidget *
gtk_handle_box_get_invisible (void)
{
  static GtkWidget *handle_box_invisible = NULL;

  if (!handle_box_invisible)
    {
      handle_box_invisible = gtk_invisible_new ();
      gtk_widget_show (handle_box_invisible);
    }

  return handle_box_invisible;
}

This is another instance of the "there is just one display and it is always 
open"-mindset of Gtk+.

I have filed a Gtk+ bug on this 
(http://bugzilla.gnome.org/show_bug.cgi?id=581110). Not sure what we should do 
about this bug though.  Keep it until Gtk+ fixes/rejects the bug report or 
close it?

        Jan D.

> Chong Yidong skrev:
> > Stephen Berman <stephen.berman@gmx.net> wrote:
> >
> > > Carrying out the following steps reliably crashes Emacs:
> > >
> > > 1. emacs -Q --daemon
> > > 2. emacsclient -c
> > > 3. Detach the tool bar (only possible with GTK+ build).
> > > 4. Close the client frame with C-x 5 0
> > > 5. emacsclient -c
> > > 6. Detach the tool bar
> > > => SIGSEGV
> >
> > Actually, daemon mode is not needed.  You can also do this:
> >
> > 1. emacs -Q -nw
> > 2. M-x make-frame-on-display RET :0.0 RET
> > 3. Detach the tool bar
> > 4. Close the client frame with C-x 5 0
> > 5. M-x make-frame-on-display RET :0.0 RET
> > 6. Detach the tool bar
> > => SIGSEGV
> >
> > Jan, could you try to debug this?  It may be another manifestation of
> > the problems we've been having with GTK and closing X connections.
>
> It looks like it.  The window for the detached tool bar is created and 
> managed by Gtk+ and is not deleted when the display is removed it seems.
>
> I'll see if we can work around it.
>
>     Jan D.