Update to Drupal 8.2.0. For more information, see https://www.drupal.org/project/drupal/releases/8.2.0

core/lib/Drupal/Component/Serialization/Yaml.php

@@ -2,42 +2,37 @@
 
 namespace Drupal\Component\Serialization;
 
-use Drupal\Component\Serialization\Exception\InvalidDataTypeException;
-use Symfony\Component\Yaml\Parser;
-use Symfony\Component\Yaml\Dumper;
-
 /**
- * Default serialization for YAML using the Symfony component.
+ * Provides a YAML serialization implementation.
+ *
+ * Proxy implementation that will choose the best library based on availability.
  */
 class Yaml implements SerializationInterface {
 
+  /**
+   * The YAML implementation to use.
+   *
+   * @var \Drupal\Component\Serialization\SerializationInterface
+   */
+  protected static $serializer;
+
   /**
    * {@inheritdoc}
    */
   public static function encode($data) {
-    try {
-      $yaml = new Dumper();
-      $yaml->setIndentation(2);
-      return $yaml->dump($data, PHP_INT_MAX, 0, TRUE, FALSE);
-    }
-    catch (\Exception $e) {
-      throw new InvalidDataTypeException($e->getMessage(), $e->getCode(), $e);
-    }
+    // Instead of using \Drupal\Component\Serialization\Yaml::getSerializer(),
+    // always using Symfony for writing the data, to reduce the risk of having
+    // differences if different environments (like production and development)
+    // do not match in terms of what YAML implementation is available.
+    return YamlSymfony::encode($data);
   }
 
   /**
    * {@inheritdoc}
    */
   public static function decode($raw) {
-    try {
-      $yaml = new Parser();
-      // Make sure we have a single trailing newline. A very simple config like
-      // 'foo: bar' with no newline will fail to parse otherwise.
-      return $yaml->parse($raw, TRUE, FALSE);
-    }
-    catch (\Exception $e) {
-      throw new InvalidDataTypeException($e->getMessage(), $e->getCode(), $e);
-    }
+    $serializer = static::getSerializer();
+    return $serializer::decode($raw);
   }
 
   /**
@@ -47,4 +42,23 @@ class Yaml implements SerializationInterface {
     return 'yml';
   }
 
+  /**
+   * Determines which implementation to use for parsing YAML.
+   */
+  protected static function getSerializer() {
+
+    if (!isset(static::$serializer)) {
+      // Use the PECL YAML extension if it is available. It has better
+      // performance for file reads and is YAML compliant.
+      if (extension_loaded('yaml')) {
+        static::$serializer = YamlPecl::class;
+      }
+      else {
+        // Otherwise, fallback to the Symfony implementation.
+        static::$serializer = YamlSymfony::class;
+      }
+    }
+    return static::$serializer;
+  }
+
 }