Pull Object to Populate Extraction Into a Trait

And use that trait in `AbstractNormalizer`.
symfony · chrisguitarguy · Feb 22, 2017 · Feb 22, 2017 · Feb 22, 2017 · Sep 27, 2017
commit ffb1e40f20ae40636b04a327b1d41438d9195a30
@@ -27,6 +27,8 @@
  */
 abstract class AbstractNormalizer extends SerializerAwareNormalizer implements NormalizerInterface, DenormalizerInterface, SerializerAwareInterface
 {
+    use ObjectToPopulateTrait;
+
     const CIRCULAR_REFERENCE_LIMIT = 'circular_reference_limit';
     const OBJECT_TO_POPULATE = 'object_to_populate';
     const GROUPS = 'groups';
@@ -317,14 +319,8 @@ protected function instantiateObject(array &$data, $class, array &$context, \Ref
             $format = null;
         }
 
-        if (
-            isset($context[static::OBJECT_TO_POPULATE]) &&
-            is_object($context[static::OBJECT_TO_POPULATE]) &&
-            $context[static::OBJECT_TO_POPULATE] instanceof $class
-        ) {
-            $object = $context[static::OBJECT_TO_POPULATE];
+        if (null != $object = $this->extractObjectToPopulate($class, $context, static::OBJECT_TO_POPULATE)) {
             unset($context[static::OBJECT_TO_POPULATE]);
-
             return $object;
         }
 

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Normalizer;
+
+trait ObjectToPopulateTrait
+{
+    /**
+     * Extract the `object_to_populate` field from the context if it exists
+     * and is an instance of the provided $class.
+     *
+     * @param string $class The class the object should be
+     * @param $context The denormalization context
+     * @param string $key They in which to look for the object to populate.
+     *        Keeps backwards compatability with `AbstractNormalizer.
+     * @return object|null An object if things check out, null otherwise.
+     */
+    protected function extractObjectToPopulate($class, array $context, $key=null)
+    {
+        $key = $key ?: 'object_to_populate';
+
+        if (
+            isset($context[$key]) &&
+            is_object($context[$key]) &&
+            $context[$key] instanceof $class
+        ) {
+            return $context[$key];
+        }
+
+        return null;
+    }
+}
@@ -0,0 +1,47 @@
+<?php
+
+namespace Symfony\Component\Serializer\Tests\Normalizer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Serializer\Normalizer\ObjectToPopulateTrait;
+use Symfony\Component\Serializer\Tests\Fixtures\ProxyDummy;
+
+class ObjectToPopulateTraitTest extends TestCase
+{
+    use ObjectToPopulateTrait;
+
+    public function testExtractObjectToPopulateReturnsNullWhenKeyIsMissing()
+    {
+        $object = $this->extractObjectToPopulate(ProxyDummy::class, []);
+
+        $this->assertNull($object);
+    }
+
+    public function testExtractObjectToPopulateReturnsNullWhenNonObjectIsProvided()
+    {
+        $object = $this->extractObjectToPopulate(ProxyDummy::class, [
+            'object_to_populate' => 'not an object',
+        ]);
+
+        $this->assertNull($object);
+    }
+
+    public function testExtractObjectToPopulateReturnsNullWhenTheClassIsNotAnInstanceOfTheProvidedClass()
+    {
+        $object = $this->extractObjectToPopulate(ProxyDummy::class, [
+            'object_to_populate' => new \stdClass(),
+        ]);
+
+        $this->assertNull($object);
+    }
+
+    public function testExtractObjectToPopulateReturnsObjectWhenEverythingChecksOut()
+    {
+        $expected = new ProxyDummy();
+        $object = $this->extractObjectToPopulate(ProxyDummy::class, [
+            'object_to_populate' => $expected,
+        ]);
+
+        $this->assertSame($expected, $object);
+    }
+}