Fix PHP Warning: array_filter() expects parameter 1 to be array, null given in subscription_options plugin (#7165)

.. when IMAP connection fails

CHANGELOG

@@ -5,6 +5,7 @@ CHANGELOG Roundcube Webmail
 - Password: Make chpass-wrapper.py Python 3 compatible (#7135)
 - Elastic: Fix bug where it was possible to switch editor mode when 'htmleditor' was in 'dont_override' (#7143)
 - Fix regression where "Open in new window" action didn't work (#7155)
+- Fix PHP Warning: array_filter() expects parameter 1 to be array, null given in subscriptions_option plugin (#7165)
 
 RELEASE 1.4.2
 -------------

plugins/subscriptions_option/subscriptions_option.php

@@ -79,13 +79,15 @@ class subscriptions_option extends rcube_plugin
 
         if (!$rcmail->config->get('use_subscriptions', true)) {
             $storage = $rcmail->get_storage();
-            $folders = $storage->list_folders_direct();
-            $folders = array_filter($folders, function($folder) use ($storage) {
-                $attrs = $storage->folder_attributes($folder);
-                return !in_array_nocase('\\Noselect', $attrs);
-            });
 
-            $args['folders'] = $folders;
+            if ($folders = $storage->list_folders_direct()) {
+                $folders = array_filter($folders, function($folder) use ($storage) {
+                    $attrs = $storage->folder_attributes($folder);
+                    return !in_array_nocase('\\Noselect', $attrs);
+                });
+
+                $args['folders'] = $folders;
+            }
         }
 
         return $args;