Merge branch '4.4' into 5.1

* 4.4:
  [Cache] Psr16Cache does not handle Proxy cache items
  [Serializer] fixed fix encoding of cache keys with anonymous classes
  Bump Symfony version to 4.4.13
  Update VERSION for 4.4.12
  Update CHANGELOG for 4.4.12
  Bump Symfony version to 3.4.45
  Update VERSION for 3.4.44
  Update CONTRIBUTORS for 3.4.44
  Update CHANGELOG for 3.4.44

Mapping/Factory/CacheClassMetadataFactory.php

@@ -51,8 +51,7 @@ public function getMetadataFor($value)
             return $this->loadedClasses[$class];
         }
 
-        // Key cannot contain backslashes according to PSR-6
-        $key = strtr($class, '\\', '_');
+        $key = rawurlencode(strtr($class, '\\', '_'));
 
         $item = $this->cacheItemPool->getItem($key);
         if ($item->isHit()) {

Tests/Mapping/Factory/CacheMetadataFactoryTest.php

@@ -63,4 +63,20 @@ public function testInvalidClassThrowsException()
 
         $factory->getMetadataFor('Not\Exist');
     }
+
+    public function testAnonymousClass()
+    {
+        $anonymousObject = new class() {
+        };
+
+        $metadata = new ClassMetadata(\get_class($anonymousObject));
+        $decorated = $this->getMockBuilder(ClassMetadataFactoryInterface::class)->getMock();
+        $decorated
+            ->expects($this->once())
+            ->method('getMetadataFor')
+            ->willReturn($metadata);
+
+        $factory = new CacheClassMetadataFactory($decorated, new ArrayAdapter());
+        $this->assertEquals($metadata, $factory->getMetadataFor($anonymousObject));
+    }
 }