updated core and modules

vendor/symfony/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);
@@ -461,6 +464,8 @@ class XmlEncoder extends SerializerAwareEncoder implements EncoderInterface, Dec
      * @param mixed    $val
      *
      * @return bool
+     *
+     * @throws UnexpectedValueException
      */
     private function selectNodeType(\DOMNode $node, $val)
     {
@@ -472,7 +477,7 @@ class XmlEncoder extends SerializerAwareEncoder implements EncoderInterface, Dec
         } elseif ($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)) {
@@ -506,7 +511,7 @@ class XmlEncoder extends SerializerAwareEncoder implements EncoderInterface, Dec
     /**
      * Create a DOM document, taking serializer options into account.
      *
-     * @param array $context options that the encoder has access to.
+     * @param array $context options that the encoder has access to
      *
      * @return \DOMDocument
      */