DOM nodes changes identity

[goetas]

Nodes created by PHP, when added to DOM, changes their identity.

$dom = new \DOMDocument('1.0', 'UTF-8');
$root = $dom->createElement('root');
$dom->appendChild($root);

// expected to be TRUE, actually FALSE
var_dump($root === $dom->documentElement);

[sgolemon]

Hrmmm. That's definitely an incompatibility with PHP5, but "fixing" it will take a fair amount of refactoring and probably just hurt perf in the end. Putting this on wishlist as we should probably find a way to make it work, but there's higher priority stuff to tackle.

[goetas]

There is also a PHP bug that is related to this.

It has a smaller side effect, but remains a unexpected behavior.

[ThomasWeinert]

Here is another effect that should be related to this issue. If you register an own class for a DOMNode descendant, the objected created by HHVM is still the superclass until the node is appended and changes its identity.

Example:

<?php
class MyElement extends \DOMElement {
 public function __get($name) { return $this->$name; } 
} 
$dom = new DOMDocument(); 
$dom->registerNodeClass('DOMElement', 'MyElement'); 
$createdNode = $dom->createElement('foo'); 
$appendedNode = $dom->appendChild($createdNode); 
var_dump(get_class($createdNode), get_class($appendedNode));

Expected:

string(9) "MyElement" 
string(9) "MyElement"

Actual:

string(10) "DOMElement" 
string(9) "MyElement"

[goetas]

@paulbiss Does it cover this?

$dom = new \DOMDocument('1.0', 'UTF-8');
$root = $dom->createElement('root');
$dom->appendChild($root);

// expected to be TRUE, actually FALSE
var_dump($root === $dom->documentElement);

I can't see anything about it in 236c308.

Nodes identity was the original scope of this issue.

[paulbiss]

@goetas put the wrong issue number in the commit message

[paulbiss]

My fix for #4126 should cover this (D1660716). It's up for internal review, I'll add this as a test.