Merge branch '3.4' into 4.0

* 3.4:
  [HttpKernel] Fix race condition when clearing old containers
  [DI] Fix infinite loop in InlineServiceDefinitionsPass
  [HttpKernel] Keep legacy container files for concurrent requests
  Do not cache cache attributes if `attributes` is in the context
  Test that it do not remove the new flashes when displaying the existing ones
  [HttpFoundation] AutExpireFlashBag should not clear new flashes
  [FrameworkBundle][Serializer] Remove YamlEncoder definition if Yaml component isn't installed
  [DI] Fix tracking of env vars in exceptions
  [Form] Don't rely on  if http-foundation isn't in FileType
  Fix merge
  substitute aliases in inline mappings
  added ability for substitute aliases when mapping in YAML is on single line
  [Console] Fix global console flag when used in chain

Author: xabbuh

Normalizer/AbstractObjectNormalizer.php

@@ -129,6 +129,10 @@ protected function getAttributes($object, $format = null, array $context)
             return $allowedAttributes;
         }
 
+        if (isset($context['attributes'])) {
+            return $this->extractAttributes($object, $format, $context);
+        }
+
         if (isset($this->attributesCache[$class])) {
             return $this->attributesCache[$class];
         }

Tests/Normalizer/ObjectNormalizerTest.php

@@ -723,6 +723,37 @@ public function testAttributesContextDenormalizeConstructor()
             'inner' => array('foo' => 'foo', 'bar' => 'bar'),
         ), DummyWithConstructorObjectAndDefaultValue::class, null, $context));
     }
+
+    public function testNormalizeSameObjectWithDifferentAttributes()
+    {
+        $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
+        $this->normalizer = new ObjectNormalizer($classMetadataFactory);
+        $serializer = new Serializer(array($this->normalizer));
+        $this->normalizer->setSerializer($serializer);
+
+        $dummy = new ObjectOuter();
+        $dummy->foo = new ObjectInner();
+        $dummy->foo->foo = 'foo.foo';
+        $dummy->foo->bar = 'foo.bar';
+
+        $dummy->bar = new ObjectInner();
+        $dummy->bar->foo = 'bar.foo';
+        $dummy->bar->bar = 'bar.bar';
+
+        $this->assertEquals(array(
+            'foo' => array(
+                'bar' => 'foo.bar',
+            ),
+            'bar' => array(
+                'foo' => 'bar.foo',
+            ),
+        ), $this->normalizer->normalize($dummy, 'json', array(
+            'attributes' => array(
+                'foo' => array('bar'),
+                'bar' => array('foo'),
+            ),
+        )));
+    }
 }
 
 class ObjectDummy