Merge branch 'xml-view-fix' into master

Refs #7073

src/View/XmlView.php

@@ -148,7 +148,9 @@ class XmlView extends View
                 if (is_numeric($alias)) {
                     $alias = $key;
                 }
-                $data[$rootNode][$alias] = $this->viewVars[$key];
+                if (array_key_exists($key, $this->viewVars)) {
+                    $data[$rootNode][$alias] = $this->viewVars[$key];
+                }
             }
         } else {
             $data = isset($this->viewVars[$serialize]) ? $this->viewVars[$serialize] : null;

tests/TestCase/View/XmlViewTest.php

@@ -118,7 +118,7 @@ class XmlViewTest extends TestCase
         $Response = new Response();
         $Controller = new Controller($Request, $Response);
         $data = [
-            '_serialize' => ['tags'],
+            '_serialize' => ['tags', 'nope'],
             '_xmlOptions' => ['format' => 'attributes'],
             'tags' => [
                     'tag' => [