keyboard: Unset current page when it gets destroyed

The current page is going to be destroyed as part of _onKeyboardGroupsChanged
cleanup, however we don't unset its pointer, and thus we'd might try to call a
function using an invalidated pointer.

So, unset the this._current_page reference when its get destroyed, connecting
to destroy signal when setting it and disconnecting when changing page.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/issues/1281

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/540

diff --git a/js/ui/keyboard.js b/js/ui/keyboard.js
index fbba2840e5890f7e48a48cd29501650a012a8cd1..a67d08f1e98f53c368108ae71a49d084047246be 100644 (file)
--- a/js/ui/keyboard.js
+++ b/js/ui/keyboard.js
@@ -1522,10 +1522,15 @@ var Keyboard = class Keyboard {
 
         if (this._current_page != null) {
             this._setCurrentLevelLatched(this._current_page, false);
+            this._current_page.disconnect(this._current_page._destroyID);
             this._current_page.hide();
+            delete this._current_page._destroyID;
         }
 
         this._current_page = layers[activeLevel];
+        this._current_page._destroyID = this._current_page.connect('destroy', () => {
+            this._current_page = null;
+        });
         this._updateCurrentPageVisible();
     }