XPath expressions can't automatically register single character prefixes #1

If the prefix or the local name is just a single character neither Document::evaluate nor Document::createExpression will resolve prefixes.

Example:

$d = new XMLDocument('<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"></s:Envelope>', 'UTF-8');
$d->evaluate('//s:Envelope', $d, $d->createNSResolver($d));

Throws an exception