update readme

Author: DavidBadura

README.md

@@ -406,6 +406,40 @@ readonly class Dto
 }
 ```
 
+### Events
+
+Another way to intervene in the extract and hydrate process is through events. 
+There are two events: `PostExtract` and `PreHydrate`.
+For this functionality we use the [symfony/event-dispatcher](https://symfony.com/doc/current/components/event_dispatcher.html).
+
+```php
+use Patchlevel\Hydrator\Cryptography\PersonalDataPayloadCryptographer;
+use Patchlevel\Hydrator\Cryptography\Store\CipherKeyStore;
+use Patchlevel\Hydrator\Metadata\Event\EventMetadataFactory;
+use Patchlevel\Hydrator\MetadataHydrator;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+use Patchlevel\Hydrator\Event\PostExtract;
+use Patchlevel\Hydrator\Event\PreHydrate;
+
+$eventDispatcher = new EventDispatcher();
+
+$eventDispatcher->addListener(
+    PostExtract::class,
+    static function (PostExtract $event): void {
+        // do something
+    }
+);
+
+$eventDispatcher->addListener(
+    PreHydrate::class,
+    static function (PreHydrate $event): void {
+        // do something
+    }
+);
+
+$hydrator = new MetadataHydrator(eventDispatcher: $eventDispatcher);
+```
+
 ### Cryptography
 
 The library also offers the possibility to encrypt and decrypt personal data.

src/Metadata/AttributeMetadataFactory.php

@@ -423,7 +423,7 @@ private function findNormalizer(ReflectionProperty $reflectionProperty, Type $ty
             $normalizer = $this->findNormalizerOnClass(new ReflectionClass($valueType->getClassName()));
 
             if ($normalizer === null) {
-                return $normalizer;
+                return null;
             }
 
             if ($normalizer instanceof TypeAwareNormalizer) {

tests/Unit/Metadata/AttributeMetadataFactoryTest.php

@@ -47,6 +47,16 @@ public function testEmptyObject(): void
         self::assertCount(0, $metadata->postHydrateCallbacks());
     }
 
+    public function testSameMetadata(): void
+    {
+        $object = new class {
+        };
+
+        $metadataFactory = new AttributeMetadataFactory();
+
+        self::assertSame($metadataFactory->metadata($object::class), $metadataFactory->metadata($object::class));
+    }
+
     public function testNotFoundProperty(): void
     {
         $this->expectException(PropertyMetadataNotFound::class);