[Serializer] Xml encoder throws exception for valid data

src/Symfony/Component/Serializer/Encoder/XmlEncoder.php

@@ -369,7 +369,10 @@ class XmlEncoder extends SerializerAwareEncoder implements EncoderInterface, Dec
         if (is_array($data) || ($data instanceof \Traversable && !$this->serializer->supportsNormalization($data, $this->format))) {
             foreach ($data as $key => $data) {
                 //Ah this is the magic @ attribute types.
-                if (0 === strpos($key, '@') && is_scalar($data) && $this->isElementNameValid($attributeName = substr($key, 1))) {
+                if (0 === strpos($key, '@') && $this->isElementNameValid($attributeName = substr($key, 1))) {
+                    if (!is_scalar($data)) {
+                        $data = $this->serializer->normalize($data, $this->format, $this->context);
+                    }
                     $parentNode->setAttribute($attributeName, $data);
                 } elseif ($key === '#') {
                     $append = $this->selectNodeType($parentNode, $data);
@@ -474,7 +477,7 @@ class XmlEncoder extends SerializerAwareEncoder implements EncoderInterface, Dec
         } elseif ($val instanceof \Traversable) {
             $this->buildXml($node, $val);
         } elseif (is_object($val)) {
-            return $this->buildXml($node, $this->serializer->normalize($val, $this->format, $this->context));
+            return $this->selectNodeType($node, $this->serializer->normalize($val, $this->format, $this->context));
         } elseif (is_numeric($val)) {
             return $this->appendText($node, (string) $val);
         } elseif (is_string($val) && $this->needsCdataWrapping($val)) {

src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php

@@ -19,11 +19,17 @@ use Symfony\Component\Serializer\Encoder\XmlEncoder;
 use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Serializer\Exception\UnexpectedValueException;
 use Symfony\Component\Serializer\Normalizer\CustomNormalizer;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 class XmlEncoderTest extends TestCase
 {
+    /**
+     * @var XmlEncoder
+     */
     private $encoder;
 
+    private $exampleDateTimeString = '2017-02-19T15:16:08+0300';
+
     protected function setUp()
     {
         $this->encoder = new XmlEncoder();
@@ -524,4 +530,89 @@ XML;
 
         return $obj;
     }
+
+    public function testEncodeXmlWithBoolValue()
+    {
+        $expectedXml = <<<'XML'
+<?xml version="1.0"?>
+<response><foo>1</foo><bar>0</bar></response>
+
+XML;
+
+        $actualXml = $this->encoder->encode(array('foo' => true, 'bar' => false), 'xml');
+
+        $this->assertEquals($expectedXml, $actualXml);
+    }
+
+    public function testEncodeXmlWithDateTimeObjectValue()
+    {
+        $xmlEncoder = $this->createXmlEncoderWithDateTimeNormalizer();
+
+        $actualXml = $xmlEncoder->encode(array('dateTime' => new \DateTime($this->exampleDateTimeString)), 'xml');
+
+        $this->assertEquals($this->createXmlWithDateTime(), $actualXml);
+    }
+
+    public function testEncodeXmlWithDateTimeObjectField()
+    {
+        $xmlEncoder = $this->createXmlEncoderWithDateTimeNormalizer();
+
+        $actualXml = $xmlEncoder->encode(array('foo' => array('@dateTime' => new \DateTime($this->exampleDateTimeString))), 'xml');
+
+        $this->assertEquals($this->createXmlWithDateTimeField(), $actualXml);
+    }
+
+    /**
+     * @return XmlEncoder
+     */
+    private function createXmlEncoderWithDateTimeNormalizer()
+    {
+        $encoder = new XmlEncoder();
+        $serializer = new Serializer(array($this->createMockDateTimeNormalizer()), array('xml' => new XmlEncoder()));
+        $encoder->setSerializer($serializer);
+
+        return $encoder;
+    }
+
+    /**
+     * @return \PHPUnit_Framework_MockObject_MockObject|NormalizerInterface
+     */
+    private function createMockDateTimeNormalizer()
+    {
+        $mock = $this->getMockBuilder('\Symfony\Component\Serializer\Normalizer\CustomNormalizer')->getMock();
+
+        $mock
+            ->expects($this->once())
+            ->method('normalize')
+            ->with(new \DateTime($this->exampleDateTimeString), 'xml', array())
+            ->willReturn($this->exampleDateTimeString);
+
+        $mock
+            ->expects($this->once())
+            ->method('supportsNormalization')
+            ->with(new \DateTime($this->exampleDateTimeString), 'xml')
+            ->willReturn(true);
+
+        return $mock;
+    }
+
+    /**
+     * @return string
+     */
+    private function createXmlWithDateTime()
+    {
+        return sprintf('<?xml version="1.0"?>
+<response><dateTime>%s</dateTime></response>
+', $this->exampleDateTimeString);
+    }
+
+    /**
+     * @return string
+     */
+    private function createXmlWithDateTimeField()
+    {
+        return sprintf('<?xml version="1.0"?>
+<response><foo dateTime="%s"/></response>
+', $this->exampleDateTimeString);
+    }
 }