shell/app: Avoid adding windows with a startup workspace twice

Changing the workspace of a window causes the window tracker to remove
and add it to the app again. If this happens from within
_shell_app_add_window() before the window has been added to the windows
list, this will cause the check that is supposed to prevent adding the
same window multiple times to fail and the window to be added twice.
The app will then be considered still running after the last window has
been closed. Then when clicking on the corresponding app icon, the shell
would attempt to switch to a NULL workspace for the closed window
instead of starting a new instance, resulting in a crash.

Changing the workspace also needs to happen after increasing the
interesting window count, because otherwise removal of the window by
the window tracker would trigger a uint underflow leading the app to be
considered running with UINT_MAX interesting windows, despite having no
windows, leading to crashes right after launching the app.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3833

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1745>

diff --git a/src/shell-app.c b/src/shell-app.c
index 7d7b5510d68dca2b3eae16ee6f816b266786439f..17b179cbab308d1f97f91b2c3e2309553bf1738e 100644 (file)
--- a/src/shell-app.c
+++ b/src/shell-app.c
@@ -1081,10 +1081,6 @@ _shell_app_add_window (ShellApp        *app,
   if (!app->running_state)
       create_running_state (app);
 
-  if (app->started_on_workspace >= 0)
-    meta_window_change_workspace_by_index (window, app->started_on_workspace, FALSE);
-  app->started_on_workspace = -1;
-
   app->running_state->window_sort_stale = TRUE;
   app->running_state->windows = g_slist_prepend (app->running_state->windows, g_object_ref (window));
   g_signal_connect_object (window, "unmanaged", G_CALLBACK(shell_app_on_unmanaged), app, 0);
@@ -1098,6 +1094,10 @@ _shell_app_add_window (ShellApp        *app,
     app->running_state->interesting_windows++;
   shell_app_sync_running_state (app);
 
+  if (app->started_on_workspace >= 0)
+    meta_window_change_workspace_by_index (window, app->started_on_workspace, FALSE);
+  app->started_on_workspace = -1;
+
   g_object_thaw_notify (G_OBJECT (app));
 
   g_signal_emit (app, shell_app_signals[WINDOWS_CHANGED], 0);