Initialize rcube instance (with options); no caches without a valid user_id

program/include/rcube.php

@@ -106,12 +106,14 @@ class rcube
   /**
    * This implements the 'singleton' design pattern
    *
+   * @param integer Options to initialize with this instance. See rcube::INIT_WITH_* constants
    * @return rcube The one and only instance
    */
-  static function get_instance()
+  static function get_instance($mode = 0)
   {
     if (!self::$instance) {
       self::$instance = new rcube();
+      self::$instance->init($mode);
     }
 
     return self::$instance;
@@ -240,8 +242,7 @@ class rcube
    */
   public function get_cache($name, $type='db', $ttl=0, $packed=true)
   {
-    if (!isset($this->caches[$name])) {
-      $userid = $this->get_user_id();
+    if (!isset($this->caches[$name]) && ($userid = $this->get_user_id())) {
       $this->caches[$name] = new rcube_cache($type, $userid, $name, $ttl, $packed);
     }
 

program/include/rcube_imap.php

@@ -3742,9 +3742,9 @@ class rcube_imap extends rcube_storage
     {
         if ($this->messages_caching && !$this->mcache) {
             $rcube = rcube::get_instance();
-            if ($dbh = $rcube->get_dbh()) {
+            if (($dbh = $rcube->get_dbh()) && ($userid = $rcube->get_user_id())) {
                 $this->mcache = new rcube_imap_cache(
-                    $dbh, $this, $rcube->get_user_id(), $this->options['skip_deleted']);
+                    $dbh, $this, $userid, $this->options['skip_deleted']);
             }
         }