[EventDispatcher] TraceableEventDispatcher resets listener priorities

c960657 · c960657 · commit 9ff6a95b496d · 2016-01-21T23:19:59.000+01:00
diff --git a/src/Symfony/Component/EventDispatcher/EventDispatcher.php b/src/Symfony/Component/EventDispatcher/EventDispatcher.php
@@ -75,6 +75,29 @@ public function getListeners($eventName = null)
         return array_filter($this->sorted);
     }
 
+    /**
+     * Gets the listener priority for a specific event.
+     *
+     * Returns null if the event or the listener does not exist.
+     *
+     * @param string   $eventName The name of the event
+     * @param callable $listener  The listener
+     *
+     * @return int|null The event listener priority
+     */
+    public function getListenerPriority($eventName, $listener)
+    {
+        if (!isset($this->listeners[$eventName])) {
+            return;
+        }
+
+        foreach ($this->listeners[$eventName] as $priority => $listeners) {
+            if (false !== ($key = array_search($listener, $listeners, true))) {
+                return $priority;
+            }
+        }
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/src/Symfony/Component/HttpKernel/Debug/TraceableEventDispatcher.php b/src/Symfony/Component/HttpKernel/Debug/TraceableEventDispatcher.php
@@ -119,6 +119,25 @@ public function getListeners($eventName = null)
         return $this->dispatcher->getListeners($eventName);
     }
 
+    /**
+     * Gets the listener priority for a specific event.
+     *
+     * Returns null if the event or the listener does not exist, or if the
+     * underlying EventDispatcher does not implement getListenerPriority().
+     *
+     * @param string   $eventName The name of the event
+     * @param callable $listener  The listener
+     *
+     * @return int|null The event listener priority
+     */
+    public function getListenerPriority($eventName, $listener)
+    {
+        // For BC reaons, getListenerPriority() is not defined on EventDispatcherInterface.
+        if (method_exists($this->dispatcher, 'getListenerPriority')) {
+            return $this->dispatcher->getListenerPriority($eventName, $listener);
+        }
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -392,10 +411,11 @@ private function preDispatch($eventName, $eventId, Event $event)
         $listeners = $this->dispatcher->getListeners($eventName);
 
         foreach ($listeners as $listener) {
+            $priority = $this->getListenerPriority($eventName, $listener);
             $this->dispatcher->removeListener($eventName, $listener);
             $wrapped = $this->wrapListener($eventName, $eventId, $listener);
             $this->wrappedListeners[$eventId][$wrapped] = $listener;
-            $this->dispatcher->addListener($eventName, $wrapped);
+            $this->dispatcher->addListener($eventName, $wrapped, $priority);
         }
 
         switch ($eventName) {
@@ -455,8 +475,10 @@ private function postDispatch($eventName, $eventId, Event $event)
         }
 
         foreach ($this->wrappedListeners[$eventId] as $wrapped) {
+            $listener = $this->wrappedListeners[$eventId][$wrapped];
+            $priority = $this->getListenerPriority($eventName, $wrapped);
             $this->dispatcher->removeListener($eventName, $wrapped);
-            $this->dispatcher->addListener($eventName, $this->wrappedListeners[$eventId][$wrapped]);
+            $this->dispatcher->addListener($eventName, $listener, $priority);
         }
 
         unset($this->wrappedListeners[$eventId]);
diff --git a/src/Symfony/Component/HttpKernel/Tests/Debug/TraceableEventDispatcherTest.php b/src/Symfony/Component/HttpKernel/Tests/Debug/TraceableEventDispatcherTest.php
@@ -58,6 +58,23 @@ public function testHasListeners()
         $this->assertTrue($tdispatcher->hasListeners('foo'));
     }
 
+    public function testGetListenerPriority()
+    {
+        $dispatcher = new EventDispatcher();
+        $tdispatcher = new TraceableEventDispatcher($dispatcher, new Stopwatch());
+
+        $tdispatcher->addListener('foo', function () {}, 123);
+
+        $listeners = $dispatcher->getListeners('foo');
+        $this->assertSame(123, $tdispatcher->getListenerPriority('foo', $listeners[0]));
+
+        // Verify that priority is preserved when listener is removed and re-added
+        // in preProcess() and postProcess().
+        $tdispatcher->dispatch('foo', new Event());
+        $listeners = $dispatcher->getListeners('foo');
+        $this->assertSame(123, $tdispatcher->getListenerPriority('foo', $listeners[0]));
+    }
+
     public function testAddRemoveSubscriber()
     {
         $dispatcher = new EventDispatcher();
