[EventDispatcher] fixed bug in EventDispatcher::disconnect if the second argument is null or ommitted

src/Symfony/Component/EventDispatcher/EventDispatcher.php

@@ -51,6 +51,11 @@ class EventDispatcher
             return false;
         }
 
+        if (null === $listener) {
+            unset($this->listeners[$name]);
+            return;
+        }
+
         foreach ($this->listeners[$name] as $priority => $callables) {
             foreach ($callables as $i => $callable) {
                 if ($listener === $callable) {

tests/Symfony/Tests/Component/EventDispatcher/EventDispatcherTest.php

@@ -30,6 +30,10 @@ class EventDispatcherTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(array('listenToBarBar'), $dispatcher->getListeners('barbar'), '->disconnect() disconnects a listener for an event name');
 
         $this->assertFalse($dispatcher->disconnect('foobar', 'listen'), '->disconnect() returns false if the listener does not exist');
+
+        $dispatcher->disconnect('bar');
+        $this->assertEquals(array(), $dispatcher->getListeners('bar'), '->disconnect() without a listener disconnects all listeners of for an event name');
+        $this->assertEquals(array('listenToBarBar'), $dispatcher->getListeners('barbar'), '->disconnect() without a listener disconnects all listeners of for an event name');
     }
 
     public function testGetHasListeners()