From: Sebastian Keller <skeller@gnome.org>
Date: Sat, 17 Apr 2021 17:53:43 +0000 (+0200)
Subject: dnd: Don't try to restore to parent location if parent got destroyed
X-Git-Tag: archive/raspbian/50.5-1+rpi1~1^2~616^2^2~30
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=79acae41769ab46a3d11851c64e14779a3035bd2;p=gnome-shell.git

dnd: Don't try to restore to parent location if parent got destroyed

The original parent of a dragged actor might have been destroyed after
the drag has been started. When the drag is canceled and _dragOrigParent
is set, the code is trying to get the current position and size of it
when restoring. With a destroyed parent this however would result in a
crash.

This could happen for example when starting a drag on a window preview
while the overview is hiding and then releasing it once the transition
is done.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4024

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1817>
---

diff --git a/js/ui/dnd.js b/js/ui/dnd.js
index 0af1e7ecc..03b56915f 100644
--- a/js/ui/dnd.js
+++ b/js/ui/dnd.js
@@ -407,6 +407,10 @@ var _Draggable = class _Draggable {
             Main.uiGroup.add_child(this._dragActor);
             Main.uiGroup.set_child_above_sibling(this._dragActor, null);
             Shell.util_set_hidden_from_pick(this._dragActor, true);
+
+            this._dragOrigParentDestroyId = this._dragOrigParent.connect('destroy', () => {
+                this._dragOrigParent = null;
+            });
         }
 
         this._dragActorDestroyId = this._dragActor.connect('destroy', () => {
@@ -776,6 +780,11 @@ var _Draggable = class _Draggable {
             this._dragActor = null;
         }
 
+        if (this._dragOrigParent) {
+            this._dragOrigParent.disconnect(this._dragOrigParentDestroyId);
+            this._dragOrigParent = null;
+        }
+
         this._dragState = DragState.INIT;
         currentDraggable = null;
     }