Merge branch '4.4' into 5.0

* 4.4:
  [Debug] fix ClassNotFoundFatalErrorHandler
  [Routing] Fix using a custom matcher & generator dumper class
  [Serializer] Fix cache in MetadataAwareNameConverter
  [Dotenv] Fixed infinite loop with missing quote followed by quoted value
  [HttpClient] Added missing sprintf
  [TwigBridge] button_widget now has its title attr translated even if its label = null or false
  [PhpUnitBridge] When using phpenv + phpenv-composer plugin, composer executable is wrapped into a bash script
  [Messenger] Added check if json_encode succeeded
  [Messenger] Added check if json_encode succeeded
  [FrameworkBundle][ContainerLintCommand] Only skip .errored. services
  [HttpClient] fix exception in case of PSR17 discovery failure
  [DependencyInjection] Handle ServiceClosureArgument for callable in container linting
  fix processing chain adapter based cache pool
  [HttpKernel] release lock explicitly
  [Security] Prevent canceled remember-me cookie from being accepted
  [FrameworkBundle][TranslationUpdateCommand] Do not output positive feedback on stderr
  [Security\Guard] Fix missing typehints
  do not render preferred choices as selected

NameConverter/MetadataAwareNameConverter.php

@@ -47,7 +47,7 @@ public function normalize(string $propertyName, string $class = null, string $fo
             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 @@ public function denormalize(string $propertyName, string $class = null, string $
         }
 
         $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 @@ private function getCacheValueForNormalization(string $propertyName, string $cla
         }
 
         $attributesMetadata = $this->metadataFactory->getMetadataFor($class)->getAttributesMetadata();
-        if (!isset($attributesMetadata[$propertyName])) {
+        if (!\array_key_exists($propertyName, $attributesMetadata)) {
             return null;
         }
 
@@ -93,7 +93,7 @@ private function normalizeFallback(string $propertyName, string $class = null, s
     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);
         }