shell/app: Keep cancellable after cancelled proxy request

When a GTK app is started, we create a corresponding GtkApplication
proxy to monitor the app's busy state. If the app is stopped before
the proxy request finishes, we cancel the cancellable before clearing
the running state.

Usually we clear the cancellable once it is no longer needed, namely
when we got the proxy. However when the request was cancelled, the
cancellable has already been cleared, and if there's a cancellable,
it belongs to another request (because the window was added again,
for example when moving between monitors).

Leave that cancellable alone in that case, so we can cancel the
second request as well if necessary to avoid a crash when trying
to set the proxy on a cleared running state.

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/1962

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1885>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/shell-app.c b/src/shell-app.c
index 62ba2ec73..1dfd82d8e 100644
--- a/src/shell-app.c
+++ b/src/shell-app.c
@@ -1046,10 +1046,11 @@ get_application_proxy (GObject      *source,
 {
   ShellApp *app = user_data;
   ShellOrgGtkApplication *proxy;
+  g_autoptr (GError) error = NULL;
 
   g_assert (SHELL_IS_APP (app));
 
-  proxy = shell_org_gtk_application_proxy_new_finish (result, NULL);
+  proxy = shell_org_gtk_application_proxy_new_finish (result, &error);
   if (proxy != NULL)
     {
       app->running_state->application_proxy = proxy;
@@ -1061,7 +1062,8 @@ get_application_proxy (GObject      *source,
         g_object_notify (G_OBJECT (app), "busy");
     }
 
-  if (app->running_state != NULL)
+  if (app->running_state != NULL &&
+      !g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
     g_clear_object (&app->running_state->cancellable);
 
   g_object_unref (app);