[gnome-shell-extensions/gnome-3-38] window-list: Stop monitoring drag operation if window list is destroyed

[Florian Müllner <fmuellner src gnome org>]

commit de8876bd5ed35d82b9d38bc403ac1682d8954675
Author: Ray Strode <rstrode redhat com>
Date:   Tue Nov 24 00:24:55 2020 -0500

    window-list: Stop monitoring drag operation if window list is destroyed
    
    If a user is in the middle of a drag in the window list and the
    window list associated with the drag gets destroyed, the drag
    monitor gets leaked.
    
    Later when the drag motion is processed, spew goes to the log:
    
    clutter_actor_contains: assertion 'CLUTTER_IS_ACTOR (self)' failed
    
    Examples of triggers for this bug:
    
    - The monitor topology changes
    - The screen gets locked during the drag
    
    This commit fixes the spew and the leak by ensuring any pending
    drag monitoring is disabled when the window lists are destroyed.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/145>
    
    (cherry picked from commit 8318ea919f2d01b12e5c14047fca02d4333be720)

 extensions/window-list/extension.js | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/extensions/window-list/extension.js b/extensions/window-list/extension.js
index 3c45d00..8babbae 100644
--- a/extensions/window-list/extension.js
+++ b/extensions/window-list/extension.js
@@ -787,9 +787,9 @@ class WindowList extends St.Widget {
             });
 
         this._dragBeginId = Main.xdndHandler.connect('drag-begin',
-            this._onDragBegin.bind(this));
+            this._monitorDrag.bind(this));
         this._dragEndId = Main.xdndHandler.connect('drag-end',
-            this._onDragEnd.bind(this));
+            this._stopMonitoringDrag.bind(this));
         this._dragMonitor = {
             dragMotion: this._onDragMotion.bind(this),
         };
@@ -1017,11 +1017,11 @@ class WindowList extends St.Widget {
         }
     }
 
-    _onDragBegin() {
+    _monitorDrag() {
         DND.addDragMonitor(this._dragMonitor);
     }
 
-    _onDragEnd() {
+    _stopMonitoringDrag() {
         DND.removeDragMonitor(this._dragMonitor);
         this._removeActivateTimeout();
     }
@@ -1095,6 +1095,7 @@ class WindowList extends St.Widget {
 
         global.display.disconnect(this._fullscreenChangedId);
 
+        this._stopMonitoringDrag();
         Main.xdndHandler.disconnect(this._dragBeginId);
         Main.xdndHandler.disconnect(this._dragEndId);