feature #20524 [Serializer][XmlEncoder] Allow removing empty tags in …

…generated XML (amoiraud)

This PR was squashed before being merged into the 3.3-dev branch (closes #20524).

Discussion
----------

[Serializer][XmlEncoder] Allow removing empty tags in generated XML

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #20398
| License       | MIT
| Doc PR        | ~

Allow a new option in $context of XmlEncoder.php to remove empty tags if $context['remove_empty_tags'] setted to true, changing this :

```xml
    <node>
         <subnode>Value</subnode>
         <emptysubnode/>
    </node>
```

To this :

```xml
    <node>
         <subnode>Value</subnode>
    </node>
```

Commits
-------

0cb4d8e [Serializer][XmlEncoder] Allow removing empty tags in generated XML

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

@@ -392,7 +392,7 @@ private function buildXml(\DOMNode $parentNode, $data, $xmlRootNodeName = null)
                     }
                 } elseif (is_numeric($key) || !$this->isElementNameValid($key)) {
                     $append = $this->appendNode($parentNode, $data, 'item', $key);
-                } else {
+                } elseif (null !== $data || !isset($this->context['remove_empty_tags']) || false === $this->context['remove_empty_tags']) {
                     $append = $this->appendNode($parentNode, $data, $key);
                 }
             }

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

@@ -138,6 +138,28 @@ public function testEncodeXmlAttributes()
         $this->assertSame($expected, $this->encoder->encode($array, 'xml', $context));
     }
 
+    public function testEncodeRemovingEmptyTags()
+    {
+        $array = array('person' => array('firstname' => 'Peter', 'lastname' => null));
+
+        $expected = '<?xml version="1.0"?>'."\n".
+            '<response><person><firstname>Peter</firstname></person></response>'."\n";
+
+        $context = array('remove_empty_tags' => true);
+
+        $this->assertSame($expected, $this->encoder->encode($array, 'xml', $context));
+    }
+
+    public function testEncodeNotRemovingEmptyTags()
+    {
+        $array = array('person' => array('firstname' => 'Peter', 'lastname' => null));
+
+        $expected = '<?xml version="1.0"?>'."\n".
+            '<response><person><firstname>Peter</firstname><lastname/></person></response>'."\n";
+
+        $this->assertSame($expected, $this->encoder->encode($array, 'xml'));
+    }
+
     public function testContext()
     {
         $array = array('person' => array('name' => 'George Abitbol'));