ParamConverterManager now checks if the value is the correct instance.

This is needed because:
    {% render 'MyVenBundle:Controller:Action', { 'entity' : entity } %}

would pass an already converted value.

Request/ParamConverter/ParamConverterManager.php

@@ -40,6 +40,13 @@ public function apply(Request $request, $configurations)
         }
 
         foreach ($configurations as $configuration) {
+            // If the value is already an instance of the class we are trying to convert it into
+            // we should continue as no convertion is required `is_a` was un-deprecated in 5.3
+            $value = $request->attributes->get($configuration->getName());
+            if (is_object($value) && is_a($value, $configuration->getClass())) {
+                continue;
+            }
+
             foreach ($this->all() as $converter) {
                 if ($converter->supports($configuration)) {
                     if ($converter->apply($request, $configuration)) {

Tests/Request/ParamConverter/ParamConverterManagerTest.php

@@ -65,6 +65,33 @@ public function testApply()
         $this->manager->apply(new Request(), $configurations);
     }
 
+    public function testApplyNotCalledOnAlreadyConvertedObjects()
+    {
+
+        $converter = $this->createParamConverterMock();
+        $converter
+            ->expects($this->never())
+            ->method('supports')
+        ;
+
+        $converter
+            ->expects($this->never())
+            ->method('apply')
+        ;
+
+        $this->manager->add($converter);
+
+        $request = new Request();
+        $request->attributes->set('converted', new \stdClass);
+
+        $configuration = new Configuration\ParamConverter(array(
+            'name' => 'converted',
+            'class' => 'stdClass',
+        ));
+
+        $this->manager->apply($request, array($configuration));
+    }
+
     protected function createParamConverterMock()
     {
         return $this->getMock('Sensio\Bundle\FrameworkExtraBundle\Request\ParamConverter\ParamConverterInterface');