Re: Gtk+ signal bug

[Owen Taylor <otaylor redhat com>]

The correct fix is really simple, in gtk_signal_handlers_destroy:

         if (handler->id > 0)
            gtk_signal_handler_unref (handler, object);

should be:

         if (handler->id > 0)
            {
               handler->id = 0;
               gtk_signal_handler_unref (handler, object);
            }

[ There are two of these ]

But since I would not like to see gtk-- depend on a new release
of GTK+, let me suggest a simple workaround:

All signal handlers are disconnected at destruction, so simply
check

 GTK_OBJECT_DESTROYED (obj)

when you are cleaning up after your proxy object, and skip
the disconnection step in that case.
 
[ The destroyed will probably go away in GTK+-1.4, but this
  should work fine for now ]

(In fact, for non-pathological cases, the explicit disconnections
are unnecessary, since for unmanaged gtk-- objects, the GTK+ widget
will be destroyed when the proxy is deleted, and for managed
objects, the proxy object will not be deleted until the GTK+
widget is finalized, which occurs after destruction.)

> Possible solutions.  
>   1) The handler could have a flag to indicate that it is already orphaned 
>      by the object and thus ignores the disconnect.
>   2) The object could remove referenced to the handlers it is abandoning.
>   3) When the object destroys, but the ref counter is still one, we
>      could call the destroy noticification which would disable the 
>      disconnect.  (handler sends disconnect notify when its object is
>      going away rather than when it is going away.)
> 
> Number 2 isn't good if we get a warnign that we are trying to
> disconnect a connection id which is already there.  
> Number 3 may be workable since in order for this to occure the 
> handler must be emitting and thus used its argument list.  However,
> there is no way to know is code depends on the handler sending
> its destroy notification late.

The above fix, and the above workaround should both work fine.

Regards,
                                        Owen