merged branch ericclemmons/2295-serializer-normalizable-traversable (PR #2578)

Commits
-------

7346896 Changed Serialized#supportsNormalization to PRIVATE
e851efc Updated SerializerTest with "normalizeTraversable" & "testNormalizeGivesPriorityToInterfaceOverTraversable"
d789f94 Serializer#normalize gives precedence to objects that support normalization
9e6ba9a Added protected Serializer#supportsNormalization

Discussion
----------

[Serializer] `normalize` should use supported normalizer before Traversable

Bug fix: yes
Feature addition: no
Backwards compatibility break: no (discussion needed)
Symfony2 tests pass: yes
Fixes the following tickets: #2295

**Same as PR #2539, except rebased onto `2.0`**

Should I abstract out a `supportsDenormalization` function just for symmetry?

Author: fabpot

Serializer.php

@@ -96,6 +96,9 @@ public function normalize($data, $format = null)
         if (null === $data || is_scalar($data)) {
             return $data;
         }
+        if (is_object($data) && $this->supportsNormalization($data, $format)) {
+            return $this->normalizeObject($data, $format);
+        }
         if ($data instanceof \Traversable) {
             $normalized = array();
             foreach ($data as $key => $val) {
@@ -153,17 +156,14 @@ private function normalizeObject($object, $format = null)
         if (!$this->normalizers) {
             throw new LogicException('You must register at least one normalizer to be able to normalize objects.');
         }
+
         $class = get_class($object);
-        if (isset($this->normalizerCache[$class][$format])) {
+
+        // If normalization is supported, cached normalizer will exist
+        if ($this->supportsNormalization($object, $format)) {
             return $this->normalizerCache[$class][$format]->normalize($object, $format);
         }
-        foreach ($this->normalizers as $normalizer) {
-            if ($normalizer->supportsNormalization($object, $class, $format)) {
-                $this->normalizerCache[$class][$format] = $normalizer;
 
-                return $normalizer->normalize($object, $format);
-            }
-        }
         throw new UnexpectedValueException('Could not normalize object of type '.$class.', no supporting normalizer found.');
     }
 
@@ -193,6 +193,31 @@ private function denormalizeObject($data, $class, $format = null)
         throw new UnexpectedValueException('Could not denormalize object of type '.$class.', no supporting normalizer found.');
     }
 
+    /**
+     * Check if normalizer cache or normalizers supports provided object, which will then be cached
+     *
+     * @param object $object Object to test for normalization support
+     * @param string $format Format name, needed for normalizers to pivot on
+     */
+    private function supportsNormalization($object, $format)
+    {
+        $class = get_class($object);
+
+        if (isset($this->normalizerCache[$class][$format])) {
+            return true;
+        }
+
+        foreach ($this->normalizers as $normalizer) {
+            if ($normalizer->supportsNormalization($object, $format)) {
+                $this->normalizerCache[$class][$format] = $normalizer;
+
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     /**
      * {@inheritdoc}
      */