PHP quirks and pitfalls [closed]

Answer 1

Serializing objects that process XML structures and then unserializing them does not restore the original XML structure:

$dom = new DOMDocument;
$dom->loadXML('');

$dom = serialize($dom);
$dom = unserialize($dom);

var_dump($dom->saveXML());
// $ Warning: DOMDocument::saveXML(): Couldn't fetch DOMDocument in ...
// $ NULL

Similarly for SimpleXML objects.