Bug fix for issue 1035

#1035

A bug in the appendNode method of Magento\Framework\Simplexml\Element.php causes values to be lost in very specific cases. This will fix it. The existing unit test for appendNode has been updated as well.

Bug: When appending a node that has an attribute and no child nodes, the code will take the code path for having children. This is because the result of $source->children() evaluates to TRUE when a node has attributes and no children.

Fix: Changing to call from [children()] to [count()] fixes the issue.

dev/tests/unit/testsuite/Magento/Framework/Simplexml/ElementTest.php

@@ -72,12 +72,12 @@ public function testAppendChild()
         $baseXml = simplexml_load_string('<root/>', 'Magento\Framework\Simplexml\Element');
         /** @var \Magento\Framework\Simplexml\Element $appendXml */
         $appendXml = simplexml_load_string(
-            '<node_a attr="abc"><node_b>text</node_b></node_a>',
+            '<node_a attr="abc"><node_b innerAttribute="xyz">text</node_b></node_a>',
             'Magento\Framework\Simplexml\Element'
         );
         $baseXml->appendChild($appendXml);
 
-        $expectedXml = '<root><node_a attr="abc"><node_b>text</node_b></node_a></root>';
+        $expectedXml = '<root><node_a attr="abc"><node_b innerAttribute="xyz">text</node_b></node_a></root>';
         $this->assertXmlStringEqualsXmlString($expectedXml, $baseXml->asNiceXml());
     }
 

lib/internal/Magento/Framework/Simplexml/Element.php

@@ -326,7 +326,7 @@ public function xmlentities($value = null)
      */
     public function appendChild($source)
     {
-        if ($source->children()) {
+        if ($source->count()) {
             $child = $this->addChild($source->getName());
         } else {
             $child = $this->addChild($source->getName(), $this->xmlentities($source));