[gnome-shell] workspacesDisplay: Disconnect MetaLater and parent signals on destroy

[Florian Müllner <fmuellner src gnome org>]

commit 8656102182da8f8d52c0cea7495aff1b43c3bf21
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Mon Aug 12 16:25:48 2019 +0200

    workspacesDisplay: Disconnect MetaLater and parent signals on destroy
    
    When the WorkspacesDisplay actor is destroyed we should remove the
    ongoing later and parent widget connections to avoid accessing an
    invalid object on callback.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/700

 js/ui/workspacesView.js | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/workspacesView.js b/js/ui/workspacesView.js
index af490e94aa..8c1ba81a6d 100644
--- a/js/ui/workspacesView.js
+++ b/js/ui/workspacesView.js
@@ -524,6 +524,22 @@ var WorkspacesDisplay = class {
         this._keyPressEventId = 0;
 
         this._fullGeometry = null;
+
+        this.actor.connect('destroy', this._onDestroy.bind(this));
+    }
+
+    _onDestroy() {
+        if (this._notifyOpacityId) {
+            let parent = this.actor.get_parent();
+            if (parent)
+                parent.disconnect(this._notifyOpacityId);
+            this._notifyOpacityId = 0;
+        }
+
+        if (this._parentSetLater) {
+            Meta.later_remove(this._parentSetLater);
+            this._parentSetLater = 0;
+        }
     }
 
     _onPan(action) {
@@ -717,7 +733,11 @@ var WorkspacesDisplay = class {
             oldParent.disconnect(this._notifyOpacityId);
         this._notifyOpacityId = 0;
 
-        Meta.later_add(Meta.LaterType.BEFORE_REDRAW, () => {
+        if (this._parentSetLater)
+            return;
+
+        this._parentSetLater = Meta.later_add(Meta.LaterType.BEFORE_REDRAW, () => {
+            this._parentSetLater = 0;
             let newParent = this.actor.get_parent();
             if (!newParent)
                 return;