Optimise serialization if output dto defined as same class

Previous push reverted a change which is beneficial to performance. Instead of re-looping over the serializer/normalizers, if the DTO output class is defined as the same as the resource, we can detect this in the 1st round of serialization

Author: silverbackdan

src/JsonLd/Serializer/ItemNormalizer.php

@@ -65,9 +65,9 @@ public function supportsNormalization($data, $format = null): bool
      */
     public function normalize($object, $format = null, array $context = [])
     {
-
         $objectClass = $this->getObjectClass($object);
         $outputClass = $this->getOutputClass($objectClass, $context);
+
         if (null !== $outputClass && !isset($context[self::IS_TRANSFORMED_TO_SAME_CLASS_CONTEXT_KEY])) {
             return parent::normalize($object, $format, $context);
         }

src/Serializer/AbstractItemNormalizer.php

@@ -92,7 +92,7 @@ public function __construct(PropertyNameCollectionFactoryInterface $propertyName
      */
     public function supportsNormalization($data, $format = null)
     {
-        if (!\is_object($data)) {
+        if (!\is_object($data) || $data instanceof \Traversable) {
             return false;
         }
 
@@ -114,13 +114,12 @@ public function hasCacheableSupportsMethod(): bool
      */
     public function normalize($object, $format = null, array $context = [])
     {
-
         if (!($isTransformed = isset($context[self::IS_TRANSFORMED_TO_SAME_CLASS_CONTEXT_KEY])) && $outputClass = $this->getOutputClass($this->getObjectClass($object), $context)) {
             if (!$this->serializer instanceof NormalizerInterface) {
                 throw new LogicException('Cannot normalize the output because the injected serializer is not a normalizer');
             }
 
-            if ($object !== $transformed = $this->transformOutput($object, $context, $outputClass)) {
+            if ($object !== $transformed = $this->transformOutput($object, $outputClass, $context)) {
                 $context['api_normalize'] = true;
                 $context['api_resource'] = $object;
                 unset($context['output'], $context['resource_class']);
@@ -646,13 +645,8 @@ protected function getDataTransformer($data, string $to, array $context = []): ?
      * For a given resource, it returns an output representation if any
      * If not, the resource is returned.
      */
-
-    protected function transformOutput($object, array $context = [], string $outputClass = null)
+    protected function transformOutput($object, string $outputClass, array $context = [])
     {
-        if (null === $outputClass) {
-            $outputClass = $this->getOutputClass($this->getObjectClass($object), $context);
-        }
-
         if (null !== $outputClass && null !== $dataTransformer = $this->getDataTransformer($object, $outputClass, $context)) {
             return $dataTransformer->transform($object, $outputClass, $context);
         }

tests/Fixtures/TestBundle/DataTransformer/OutputDtoUnmodifiedDataTransformer.php

@@ -18,7 +18,7 @@
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\DummyDtoOutputFallbackToSameClass;
 
 /**
- * OutputDtoUnmodifiedDataTransformer
+ * OutputDtoUnmodifiedDataTransformer.
  *
  * @author Daniel West <[email protected]>
  */

tests/Fixtures/TestBundle/Dto/OutputDtoDummy.php

@@ -14,9 +14,10 @@
 namespace ApiPlatform\Core\Tests\Fixtures\TestBundle\Dto;
 
 /**
- * OutputDtoDummy
+ * OutputDtoDummy.
  *
  * @author Daniel West <[email protected]>
  */
 class OutputDtoDummy
-{}
+{
+}