Bug #49490 [Com]: XPath namespace prefix conflict

Edit report at http://bugs.php.net/bug.php?id=49490&edit=1

 ID:               49490
 Comment by:       thomas at weinert dot info
 Reported by:      olav dot morken at uninett dot no
 Summary:          XPath namespace prefix conflict
 Status:           Open
 Type:             Bug
 Package:          DOM XML related
 Operating System: Linux (Debian)
 PHP Version:      5.3.0

 New Comment:

It looks like DOMXPath->evaluate()/DOMXPath->query() registers the
namespace prefixes of the given context and overrides any definition
from DOMXPath->registerNamespace(). PHP should not register any
namespaces from the context or at least prefer manual registrations over
automatic.

Reproduce code:
---------------
$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);

//get context node and check "a:foo"
$context = $dom->documentElement->firstChild;
var_dump($context->tagName);

// try to override the context node
$xpath->registerNamespace('a', 'urn:b');
var_dump(
  $xpath->evaluate(
    'descendant-or-self::a:*',
    $context
  )->item(0)->tagName
);

// use a prefix not used in context
$xpath->registerNamespace('prefix', 'urn:b');
var_dump(
  $xpath->evaluate(
    'descendant-or-self::prefix:*',
    $context
  )->item(0)->tagName
);

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

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


Previous Comments:
------------------------------------------------------------------------
[2009-09-07 08:41:26] olav dot morken at uninett dot no

Description:
------------
When processing an XML document with namespaces, an XPath query for a
node with a different namespace but the same namespace prefix fails.

This appears to be a conflict between the XPath namespaces and the
document namespaces. It works if either:
- The prefix in the query is replaced with a prefix that doesn't
  exist in the document.
- If the prefix in the query matches the prefix in the document.

This was tested with:
- PHP 5.3 from debian experimental: 5.3.0-3
- libxml2 2.7.3.dfsg-2.1


Reproduce code:
---------------
$doc = new DOMDocument();
$doc->loadXML('<prefix:root xmlns:prefix="urn:a" />');

$xp = new DOMXPath($doc);
$xp->registerNamespace('prefix', 'urn:b');

echo($xp->query('//prefix:root')->length . "\n");


Expected result:
----------------
It should not find the root node, since we ask for a node in a different
prefix. I.e. it should print '0'.



Actual result:
--------------
It finds the root node, i.e. it prints '1'.





------------------------------------------------------------------------



-- 
Edit this bug report at http://bugs.php.net/bug.php?id=49490&edit=1