Description:
------------
DOMXpath currently registers namespaces of the current context or the document element automatically. This results in broken and inconsistent results (Bug #49490). An argument has been added to evaluate() and query() to change this behavior. The current situation is that the argument and the context argument has ALWAYS to be used to have predictable results.

A better way would be an option on the DOMXpath object.

An option would not only mean less code, it will also allow to just change one part (initialization of ones DOMXpath instance), without the need to modify all occurrences evaluate()/query() in existing source.


Test script:
---------------
<?php

$dom = new DOMDocument();
$dom->loadXML(
  '<foobar><a:foo xmlns:a="urn:a">'.
  '<b:bar xmlns:b="urn:b"/></a:foo>'.
  '</foobar>'
);
$xpath = new DOMXPath($dom);
// disable automatic namespace registration
$xpath->enableRegisterNodeNS = FALSE;

$context = $dom->documentElement->firstChild;

$xpath->registerNamespace('a', 'urn:b');
var_dump(
  $xpath->evaluate(
    'descendant-or-self::a:*',
    $context
  )->item(0)->tagName
);
?>

Expected result:
----------------
string(5) "b:bar" 

Actual result:
--------------
string(5) "a:foo"