refactor: don't setup $ACT in ActionRouter constructor

This caused problems with using the ActionRouter in actionOK, because
actionOK is first called during the initialization of $INFO, which in
turn must be initialized for checking modes like admin.

See
#1933 (comment)
#1933 (comment)

inc/ActionRouter.php

@@ -32,21 +32,13 @@ class ActionRouter {
 
     /**
      * ActionRouter constructor. Singleton, thus protected!
-     *
-     * Sets up the correct action based on the $ACT global. Writes back
-     * the selected action to $ACT
      */
     protected function __construct() {
-        global $ACT;
         global $conf;
 
         $this->disabled = explode(',', $conf['disableactions']);
         $this->disabled = array_map('trim', $this->disabled);
         $this->transitions = 0;
-
-        $ACT = act_clean($ACT);
-        $this->setupAction($ACT);
-        $ACT = $this->action->getActionName();
     }
 
     /**
@@ -62,6 +54,17 @@ public static function getInstance($reinit = false) {
         return self::$instance;
     }
 
+    /**
+     * Sets up the correct action based on the $ACT global. Writes back the selected action to $ACT
+     */
+    public function setupACT() {
+        global $ACT;
+
+        $ACT = act_clean($ACT);
+        $this->setupAction($ACT);
+        $ACT = $this->action->getActionName();
+    }
+
     /**
      * Setup the given action
      *

inc/actions.php

@@ -14,6 +14,7 @@
 function act_dispatch(){
     // always initialize on first dispatch (test request may dispatch mutliple times on one request)
     $router = \dokuwiki\ActionRouter::getInstance(true);
+    $router->setupACT();
 
     $headers = array('Content-Type: text/html; charset=utf-8');
     trigger_event('ACTION_HEADERS_SEND',$headers,'act_sendheaders');