[Serializer] Rewrite AbstractObjectNormalizer::createChildContext() to use the provided cache_key from original context when creating child contexts

amne · amne · commit 96af30f1faf4 · 2024-01-12T15:45:05.000+02:00
If the normalization starts with an initial 'cache_key' it is currently discarded when creating child contexts. This change fixes that.
The main reason behind it is that if the client code sends a unique identifier (ApiPlatform injects the IRI) and we have a use case
that iterates a big resultset we end up with a big private cache that quickly runs out of allowed memory. The solution should be to
send a 'cache_key' which ignores the entire cache key calculation that hashes the context.
diff --git a/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php
@@ -153,9 +153,7 @@ public function supportsNormalization(mixed $data, string $format = null /* , ar
      */
     public function normalize(mixed $object, string $format = null, array $context = [])
     {
-        if (!isset($context['cache_key'])) {
-            $context['cache_key'] = $this->getCacheKey($format, $context);
-        }
+        $context['cache_key'] = $this->getCacheKey($format, $context);
 
         $this->validateCallbackContext($context);
 
@@ -287,8 +285,6 @@ abstract protected function extractAttributes(object $object, string $format = n
 
     /**
      * Gets the attribute value.
-     *
-     * @return mixed
      */
     abstract protected function getAttributeValue(object $object, string $attribute, string $format = null, array $context = []);
 
@@ -302,14 +298,9 @@ public function supportsDenormalization(mixed $data, string $type, string $forma
         return class_exists($type) || (interface_exists($type, false) && null !== $this->classDiscriminatorResolver?->getMappingForClass($type));
     }
 
-    /**
-     * @return mixed
-     */
     public function denormalize(mixed $data, string $type, string $format = null, array $context = [])
     {
-        if (!isset($context['cache_key'])) {
-            $context['cache_key'] = $this->getCacheKey($format, $context);
-        }
+        $context['cache_key'] = $this->getCacheKey($format, $context);
 
         $this->validateCallbackContext($context);
 
@@ -734,7 +725,13 @@ private function isMaxDepthReached(array $attributesMetadata, string $class, str
     protected function createChildContext(array $parentContext, string $attribute, ?string $format): array
     {
         $context = parent::createChildContext($parentContext, $attribute, $format);
-        $context['cache_key'] = $this->getCacheKey($format, $context);
+        if (isset($context['cache_key'])) {
+            if (false !== $context['cache_key']) {
+                $context['cache_key'] .= '-'.$attribute;
+            }
+        } else {
+            $context['cache_key'] = $this->getCacheKey($format, $context);
+        }
 
         return $context;
     }
@@ -746,6 +743,10 @@ protected function createChildContext(array $parentContext, string $attribute, ?
      */
     private function getCacheKey(?string $format, array $context): bool|string
     {
+        if (isset($context['cache_key'])) {
+            return $context['cache_key'];
+        }
+
         foreach ($context[self::EXCLUDE_FROM_CACHE_KEY] ?? $this->defaultContext[self::EXCLUDE_FROM_CACHE_KEY] as $key) {
             unset($context[$key]);
         }
diff --git a/src/Symfony/Component/Serializer/Tests/Normalizer/AbstractObjectNormalizerTest.php b/src/Symfony/Component/Serializer/Tests/Normalizer/AbstractObjectNormalizerTest.php
@@ -788,6 +788,43 @@ public function supportsNormalization(mixed $data, string $format = null, array
         $this->assertSame('called', $object->bar);
     }
 
+    public function testChildContextKeepsOriginalContextCacheKey()
+    {
+        $foobar = new Dummy();
+        $foobar->foo = new EmptyDummy();
+        $foobar->bar = 'bar';
+        $foobar->baz = 'baz';
+        $data = [
+            'foo' => [],
+            'bar' => 'bar',
+            'baz' => 'baz',
+        ];
+
+        $normalizer = new class() extends AbstractObjectNormalizerDummy {
+            protected function extractAttributes(object $object, string $format = null, array $context = []): array
+            {
+                return array_keys((array) $object);
+            }
+
+            protected function getAttributeValue(object $object, string $attribute, string $format = null, array $context = []): mixed
+            {
+                return $object->{$attribute};
+            }
+
+            protected function createChildContext(array $parentContext, string $attribute, ?string $format): array
+            {
+                $childContext = parent::createChildContext($parentContext, $attribute, $format);
+                AbstractObjectNormalizerTest::assertSame('hardcoded-'.$attribute, $childContext['cache_key']);
+
+                return $childContext;
+            }
+        };
+
+        $serializer = new Serializer([$normalizer]);
+        $normalizedObject = $serializer->normalize($foobar, null, ['cache_key' => 'hardcoded']);
+        $this->assertSame($data, $normalizedObject);
+    }
+
     public function testDenormalizeUnionOfEnums()
     {
         $serializer = new Serializer([
