From 6449f9299c7588d64cd36caf0367c5ee7851150a Mon Sep 17 00:00:00 2001
From: Bastien Jaillot <bjaillot@jolicode.com>
Date: Tue, 7 Jan 2020 22:43:22 +0100
Subject: [PATCH] [Serializer] Fix cache in MetadataAwareNameConverter

`isset` is used to test existence of values that is
`null` by default, which result to always bypass the cache
and force to do the calculate all the time.

This is a critical perf improvement in prod mode for an api.

Ref #35085
---
 .../NameConverter/MetadataAwareNameConverter.php          | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Symfony/Component/Serializer/NameConverter/MetadataAwareNameConverter.php b/src/Symfony/Component/Serializer/NameConverter/MetadataAwareNameConverter.php
index bbf70eaac3..a3ffaa3df5 100644
--- a/src/Symfony/Component/Serializer/NameConverter/MetadataAwareNameConverter.php
+++ b/src/Symfony/Component/Serializer/NameConverter/MetadataAwareNameConverter.php
@@ -47,7 +47,7 @@ final class MetadataAwareNameConverter implements AdvancedNameConverterInterface
             return $this->normalizeFallback($propertyName, $class, $format, $context);
         }
 
-        if (!isset(self::$normalizeCache[$class][$propertyName])) {
+        if (!\array_key_exists($class, self::$normalizeCache) || !\array_key_exists($propertyName, self::$normalizeCache[$class])) {
             self::$normalizeCache[$class][$propertyName] = $this->getCacheValueForNormalization($propertyName, $class);
         }
 
@@ -64,7 +64,7 @@ final class MetadataAwareNameConverter implements AdvancedNameConverterInterface
         }
 
         $cacheKey = $this->getCacheKey($class, $context);
-        if (!isset(self::$denormalizeCache[$cacheKey][$propertyName])) {
+        if (!\array_key_exists($cacheKey, self::$denormalizeCache) || !\array_key_exists($propertyName, self::$denormalizeCache[$cacheKey])) {
             self::$denormalizeCache[$cacheKey][$propertyName] = $this->getCacheValueForDenormalization($propertyName, $class, $context);
         }
 
@@ -78,7 +78,7 @@ final class MetadataAwareNameConverter implements AdvancedNameConverterInterface
         }
 
         $attributesMetadata = $this->metadataFactory->getMetadataFor($class)->getAttributesMetadata();
-        if (!isset($attributesMetadata[$propertyName])) {
+        if (!\array_key_exists($propertyName, $attributesMetadata)) {
             return null;
         }
 
@@ -93,7 +93,7 @@ final class MetadataAwareNameConverter implements AdvancedNameConverterInterface
     private function getCacheValueForDenormalization(string $propertyName, string $class, array $context): ?string
     {
         $cacheKey = $this->getCacheKey($class, $context);
-        if (!isset(self::$attributesMetadataCache[$cacheKey])) {
+        if (!\array_key_exists($cacheKey, self::$attributesMetadataCache)) {
             self::$attributesMetadataCache[$cacheKey] = $this->getCacheValueForAttributesMetadata($class, $context);
         }