From 18f7970d80ed40ec3da3e4925abdc129c184082b Mon Sep 17 00:00:00 2001
From: Ivan Hermanov <iwan.germanow@gmail.com>
Date: Fri, 21 Feb 2020 16:20:29 +0200
Subject: [PATCH] Fix #16334: Serializer support `\JsonSerializable`

---
 framework/CHANGELOG.md                  |  1 +
 framework/rest/Serializer.php           |  4 ++-
 tests/framework/rest/SerializerTest.php | 38 +++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 5d50319ef5..01e2f6e24e 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.33 under development
 ------------------------
 
+- Bug #16334: Serializer support `\JsonSerializable` (germanow)
 - Bug #17798: Avoid creating folder for stream log targets in `FileTarget` (wapmorgan)
 - Bug #17850: Update to `ReplaceArrayValue` config exception message (alex-code)
 - Bug #17843: Fix `yii\web\Session::setCookieParamsInternal` check param "samesite" (schevgeny)
diff --git a/framework/rest/Serializer.php b/framework/rest/Serializer.php
index 8105eb3697..d63c14b763 100644
--- a/framework/rest/Serializer.php
+++ b/framework/rest/Serializer.php
@@ -137,7 +137,7 @@ class Serializer extends Component
      * Serializes the given data into a format that can be easily turned into other formats.
      * This method mainly converts the objects of recognized types into array representation.
      * It will not do conversion for unknown object types or non-object data.
-     * The default implementation will handle [[Model]] and [[DataProviderInterface]].
+     * The default implementation will handle [[Model]], [[DataProviderInterface]] and [\JsonSerializable](https://www.php.net/manual/ru/class.jsonserializable.php).
      * You may override this method to support more object types.
      * @param mixed $data the data to be serialized.
      * @return mixed the converted data.
@@ -146,6 +146,8 @@ class Serializer extends Component
     {
         if ($data instanceof Model && $data->hasErrors()) {
             return $this->serializeModelErrors($data);
+        } elseif ($data instanceof \JsonSerializable) {
+            return $data->jsonSerialize();
         } elseif ($data instanceof Arrayable) {
             return $this->serializeModel($data);
         } elseif ($data instanceof DataProviderInterface) {
diff --git a/tests/framework/rest/SerializerTest.php b/tests/framework/rest/SerializerTest.php
index 1bfe7805cc..fb0334bf53 100644
--- a/tests/framework/rest/SerializerTest.php
+++ b/tests/framework/rest/SerializerTest.php
@@ -414,6 +414,17 @@ class SerializerTest extends TestCase
 
         $this->assertEquals($expectedResult, $serializer->serialize($dataProvider));
     }
+
+    /**
+     * @see https://github.com/yiisoft/yii2/issues/16334
+     */
+    public function testSerializeJsonSerializable()
+    {
+        $serializer = new Serializer();
+        $model = new TestModel3();
+
+        $this->assertEquals(['customField' => 'test3/test4'], $serializer->serialize($model));
+    }
 }
 
 class TestModel extends Model
@@ -457,3 +468,30 @@ class TestModel2 extends Model
         return static::$extraFields;
     }
 }
+
+class TestModel3 extends Model implements \JsonSerializable
+{
+    public static $fields = ['field3', 'field4'];
+    public static $extraFields = [];
+
+    public $field3 = 'test3';
+    public $field4 = 'test4';
+    public $extraField4 = 'testExtra2';
+
+    public function fields()
+    {
+        return static::$fields;
+    }
+
+    public function extraFields()
+    {
+        return static::$extraFields;
+    }
+
+    public function jsonSerialize()
+    {
+        return [
+            'customField' => $this->field3.'/'.$this->field4,
+        ];
+    }
+}