Add option to include interface metadata

DependencyInjection/Configuration.php

@@ -183,6 +183,7 @@ private function addMetadataSection(NodeBuilder $builder)
                             ->scalarNode('dir')->defaultValue('%kernel.cache_dir%/jms_serializer')->end()
                         ->end()
                     ->end()
+                    ->booleanNode('include_interfaces')->defaultFalse()->end()
                     ->booleanNode('auto_detection')->defaultTrue()->end()
                     ->booleanNode('infer_types_from_doctrine_metadata')
                         ->info('Infers type information from Doctrine metadata if no explicit type has been defined for a property.')

DependencyInjection/JMSSerializerExtension.php

@@ -116,7 +116,8 @@ public function loadInternal(array $config, ContainerBuilder $container)
 
         $container
             ->getDefinition('jms_serializer.metadata_factory')
-            ->replaceArgument(2, $config['metadata']['debug']);
+            ->replaceArgument(2, $config['metadata']['debug'])
+            ->addMethodCall('setIncludeInterfaces', [$config['metadata']['include_interfaces']]);
 
         // warmup
         if (!empty($config['metadata']['warmup']['paths']['included']) && class_exists(Finder::class)) {

Resources/doc/configuration.rst

@@ -192,6 +192,8 @@ values:
                 file_cache:
                     dir: "%kernel.cache_dir%/serializer"
 
+                include_interfaces: true
+
                 # Using auto-detection, the mapping files for each bundle will be
                 # expected in the Resources/config/serializer directory.
                 #

Tests/DependencyInjection/Fixture/IncludeInterfaces/AnInterface.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces;
+
+use JMS\Serializer\Annotation\Discriminator;
+
+/**
+ * @Discriminator(
+ *     field="type",
+ *     map={
+ *         "a": "JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces\AnInterfaceImplementation"
+ *     }
+ * )
+ */
+interface AnInterface
+{
+    public function execute(): void;
+}

Tests/DependencyInjection/Fixture/IncludeInterfaces/AnInterfaceImplementation.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces;
+
+use JMS\Serializer\Annotation\Type;
+
+class AnInterfaceImplementation implements AnInterface
+{
+    /**
+     * @Type("string")
+     */
+    private $bar;
+
+    public function __construct(string $bar)
+    {
+        $this->bar = $bar;
+    }
+
+    public function execute(): void
+    {
+        $this->bar = 'overwrite';
+    }
+}

Tests/DependencyInjection/Fixture/IncludeInterfaces/AnObject.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces;
+
+use JMS\Serializer\Annotation\Type;
+
+class AnObject
+{
+    /**
+     * @Type("string")
+     */
+    private $foo;
+
+    /**
+     * @Type("JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces\AnInterface")
+     */
+    private $bar;
+
+    public function __construct(string $foo, AnInterface $bar)
+    {
+        $this->foo = $foo;
+        $this->bar = $bar;
+    }
+}

Tests/DependencyInjection/JMSSerializerExtensionTest.php

@@ -12,6 +12,8 @@
 use JMS\Serializer\Metadata\Driver\TypedPropertiesDriver;
 use JMS\Serializer\SerializationContext;
 use JMS\SerializerBundle\JMSSerializerBundle;
+use JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces\AnInterfaceImplementation;
+use JMS\SerializerBundle\Tests\DependencyInjection\Fixture\IncludeInterfaces\AnObject;
 use JMS\SerializerBundle\Tests\DependencyInjection\Fixture\ObjectUsingExpressionLanguage;
 use JMS\SerializerBundle\Tests\DependencyInjection\Fixture\ObjectUsingExpressionProperties;
 use JMS\SerializerBundle\Tests\DependencyInjection\Fixture\SimpleObject;
@@ -644,6 +646,36 @@ public function testTypedDriverIsEnabled()
         self::assertSame('int', $metadata->propertyMetadata['foo']->type['name']);
     }
 
+    public function testIncludeInterfaces()
+    {
+        $container = $this->getContainerForConfig([
+            [
+                'metadata' => [
+                    'include_interfaces' => true,
+                ],
+            ]
+        ]);
+        $serializer = $container->get('jms_serializer');
+
+        $actual = $serializer->toArray(
+            new AnObject(
+                'foo',
+                new AnInterfaceImplementation(
+                    'bar'
+                )
+            )
+        );
+        $expected = [
+            'foo' => 'foo',
+            'bar' => [
+                'bar' => 'bar',
+                'type' => 'a',
+            ],
+        ];
+
+        self::assertSame($expected, $actual);
+    }
+
     private function getContainerForConfigLoad(array $configs, ?callable $configurator = null)
     {
         $bundle = new JMSSerializerBundle();