symfony
diff --git a/‎src/Symfony/Component/Serializer/Encoder/XmlEncoder.php‎
Lines changed: 13 additions & 3 deletions b/‎src/Symfony/Component/Serializer/Encoder/XmlEncoder.php‎
Lines changed: 13 additions & 3 deletions
diff --git a/‎src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php‎
Lines changed: 14 additions & 0 deletions b/‎src/Symfony/Component/Serializer/Tests/Encoder/XmlEncoderTest.php‎
Lines changed: 14 additions & 0 deletions
@@ -22,6 +22,7 @@
  * @author John Wards <jwards@whiteoctober.co.uk>
  * @author Fabian Vogler <fabian@equivalence.ch>
  * @author Kévin Dunglas <dunglas@gmail.com>
+ * @author Dany Maillard <danymaillard93b@gmail.com>
  */
 class XmlEncoder implements EncoderInterface, DecoderInterface, NormalizationAwareInterface, SerializerAwareInterface
 {
@@ -226,6 +227,13 @@ final protected function appendDocumentFragment(\DOMNode $node, $fragment): bool
         return false;
     }
 
+    private function appendComment(\DOMNode $node, string $data): bool
+    {
+        $node->appendChild($this->dom->createComment($data));
+
+        return true;
+    }
+
     /**
      * Checks the name is a valid xml element name.
      */
@@ -364,8 +372,8 @@ private function buildXml(\DOMNode $parentNode, $data, string $xmlRootNodeName =
                         $data = $this->serializer->normalize($data, $this->format, $this->context);
                     }
                     $parentNode->setAttribute($attributeName, $data);
-                } elseif ('#' === $key) {
-                    $append = $this->selectNodeType($parentNode, $data);
+                } elseif ('#' === $key[0]) { // # or #comment
+                    $append = $this->selectNodeType($parentNode, $data, $key);
                 } elseif (\is_array($data) && false === is_numeric($key)) {
                     // Is this array fully numeric keys?
                     if (ctype_digit(implode('', array_keys($data)))) {
@@ -445,7 +453,7 @@ private function needsCdataWrapping(string $val): bool
      *
      * @throws NotEncodableValueException
      */
-    private function selectNodeType(\DOMNode $node, $val): bool
+    private function selectNodeType(\DOMNode $node, $val, $key = null): bool
     {
         if (\is_array($val)) {
             return $this->buildXml($node, $val);
@@ -460,6 +468,8 @@ private function selectNodeType(\DOMNode 
FE09
$node, $val): bool
             return $this->appendText($node, (string) $val);
         } elseif (\is_string($val) && $this->needsCdataWrapping($val)) {
             return $this->appendCData($node, $val);
+        } elseif ('#comment' === $key) {
+            return $this->appendComment($node, $val);
         } elseif (\is_string($val)) {
             return $this->appendText($node, $val);
         } elseif (\is_bool($val)) {
 
@@ -760,6 +760,20 @@ public function testEncodeXmlWithDateTimeObjectField()
         $this->assertEquals($this->createXmlWithDateTimeField(), $actualXml);
     }
 
+    public function testEncodeComment()
+    {
+        $expected = <<<'XML'
+<?xml version="1.0"?>
+<response><!-- foo --></response>
+
+XML;
+
+        $data = array('#comment' => ' foo ');
+
+
+        $this->assertEquals($expected, $this->encoder->encode($data, 'xml'));
+    }
+
     /**
      * @return XmlEncoder
      */