[gnome-shell] windowManager: detect change to a non-existent WS

[Florian Müllner <fmuellner src gnome org>]

commit d75a3484d664139b5e8c8acc9818eb475e8d672e
Author: Sergio Costas <raster rastersoft com>
Date:   Thu Jan 24 23:06:48 2019 +0100

    windowManager: detect change to a non-existent WS
    
    When using dynamic workspaces, it is possible to try to change to a
    non-existent one if the user defines hotkeys for changing to desktop
    1, 2, 3... This case is not detected, and gnome shell shows an error:
    
    JS ERROR: TypeError: workspace is null
    actionMoveWorkspace@resource:///org/gnome/shell/ui/windowManager.js:2130:13
    wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
    _showWorkspaceSwitcher@resource:///org/gnome/shell/ui/windowManager.js:2104:13
    wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
    
    This patch adds a check before trying to change the workspace, to avoid
    switching to a non-existent one.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/365

 js/ui/windowManager.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/js/ui/windowManager.js b/js/ui/windowManager.js
index fedee72d5..a8b4f8e69 100644
--- a/js/ui/windowManager.js
+++ b/js/ui/windowManager.js
@@ -2086,7 +2086,7 @@ var WindowManager = new Lang.Class({
 
             direction = Meta.MotionDirection[target.toUpperCase()];
             newWs = workspaceManager.get_active_workspace().get_neighbor(direction);
-        } else if (target > 0) {
+        } else if ((target > 0) && (target <= workspaceManager.n_workspaces)) {
             target--;
             newWs = workspaceManager.get_workspace_by_index(target);