[gnome-shell] workspacesView: Only animate on show() when geometries are already set

[Florian Müllner <fmuellner src gnome org>]

commit af543daf1c35718a07d6b4ee31fd6e0214285693
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Wed May 20 13:39:11 2020 +0200

    workspacesView: Only animate on show() when geometries are already set
    
    Animating the window clones of the overview requires the fullGeometry
    and the actualGeometry to be set, which they won't be when showing the
    overview for the first time. So don't even try to animate the window
    clones in that case because the geometries will still be null and
    accessing them in workspace.js will throw errors.
    
    The workspace views will still get the correct layout as soon as the
    allocations happen because syncing the geometries will trigger updating
    the window positions. Since animations are disabled for position changes
    when syncing the geometry though, we won't get an animation and the
    clones will jump into place. That's not a regression though since before
    this change we also didn't animate in that case because the geometries
    used were simply wrong (the actualGeometry was 0-sized as explained in
    the last commit).
    
    If we wanted to fix the initial animation of the overview, we'd have to
    always enable animations of the window clones when syncing geometries,
    but that would break the animation of the workspace when hovering the
    workspaceThumbnail slider, because right now those animations are "glued
    together" using the actualGeometry, so they would get out of sync.
    
    The reason there are no errors happening in workspace.js with the
    existing code is that due to a bug in Clutter the fullGeometry of
    WorkspacesDisplay gets set very early while mapping the WorkspacesViews
    (because the overviews ControlsManager gets an allocation during the
    resource scale calculation of a ClutterClone, see
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1181), so it
    won't be set to null anymore when calling
    WorkspacesView.animateToOverview().
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1119

 js/ui/workspacesView.js | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)
---
diff --git a/js/ui/workspacesView.js b/js/ui/workspacesView.js
index e33528db0f..a4ed18d486 100644
--- a/js/ui/workspacesView.js
+++ b/js/ui/workspacesView.js
@@ -615,13 +615,16 @@ class WorkspacesDisplay extends St.Widget {
     animateToOverview(fadeOnPrimary) {
         this.show();
         this._updateWorkspacesViews();
-        for (let i = 0; i < this._workspacesViews.length; i++) {
-            let animationType;
-            if (fadeOnPrimary && i == this._primaryIndex)
-                animationType = AnimationType.FADE;
-            else
-                animationType = AnimationType.ZOOM;
-            this._workspacesViews[i].animateToOverview(animationType);
+
+        if (this._actualGeometry && this._fullGeometry) {
+            for (let i = 0; i < this._workspacesViews.length; i++) {
+                let animationType;
+                if (fadeOnPrimary && i == this._primaryIndex)
+                    animationType = AnimationType.FADE;
+                else
+                    animationType = AnimationType.ZOOM;
+                this._workspacesViews[i].animateToOverview(animationType);
+            }
         }
 
         this._restackedNotifyId =