[FrameworkBundle][Serializer] Remove YamlEncoder definition if Yaml component isn't installed

Author: ogizanagi

DependencyInjection/FrameworkExtension.php

@@ -56,6 +56,7 @@
 use Symfony\Component\Validator\ObjectInitializerInterface;
 use Symfony\Component\WebLink\HttpHeaderSerializer;
 use Symfony\Component\Workflow;
+use Symfony\Component\Yaml\Yaml;
 
 /**
  * FrameworkExtension.
@@ -1172,6 +1173,10 @@ private function registerSerializerConfiguration(array $config, ContainerBuilder
             $container->removeDefinition('serializer.normalizer.object');
         }
 
+        if (!class_exists(Yaml::class)) {
+            $container->removeDefinition('serializer.encoder.yaml');
+        }
+
         $serializerLoaders = array();
         if (isset($config['enable_annotations']) && $config['enable_annotations']) {
             if (!$this->annotationsConfigEnabled) {