Edit report at http://bugs.php.net/bug.php?id=52373&edit=1

 ID:                 52373
 Comment by:         bugs dot php dot net at moesen dot nu
 Reported by:        david at sickmiller dot com
 Summary:            XPath returns inconsistent results
 Status:             Open
 Type:               Bug
 Package:            DOM XML related
 Operating System:   Cent OS 5
 PHP Version:        5.2.13
 Block user comment: N

 New Comment:

I cannot reproduce this either.



$ cat /etc/issue

Debian GNU/Linux squeeze/sid \n \l



$ php --version

PHP 5.3.3-0.dotdeb.0 with Suhosin-Patch (cli) (built: Jul 24 2010
01:12:50) 

$ dpkg --list | grep libxml2

ii  libxml2         2.7.7.dfsg-2         GNOME XML library


Previous Comments:
------------------------------------------------------------------------
[2010-07-19 09:09:44] david at sickmiller dot com

I wonder if this may be related to the libxml2 library.  I am using
v2.6.26-2.1.2.8 from the CentOS distribution.

------------------------------------------------------------------------
[2010-07-19 07:59:35] m dot philipp at coreto dot de

Cannot repeat with php 5.3.2.

All test runs resulted in: 

"In 10000 instances, found 1 match(es) for
/root[1]/fie...@attr1='val1']"

------------------------------------------------------------------------
[2010-07-19 01:37:51] david at sickmiller dot com

Description:
------------
Sometimes the DOMXpath->evaluate() function returns unreliable results. 
This seems to happen when the document has at least a depth of 3 and
selectors are used at multiple levels.  There may be other conditions
that trigger it; I'm not sure.  The test script below is consistently
showing errors for me.

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

$rawxml = '<?xml version="1.0"?><root><field attr1="val1"><field
attr1="val1"/></field></root>';

$rawxpath = "/root[1]/fie...@attr1='val1']";



$results = array();

for ($i = 0; $i < 10000; $i++) {

        $xmlDocument = new DOMDocument();

        $xmlDocument->loadXML($rawxml);

        $xp = new DOMXPath($xmlDocument);

        $xpr = $xp->evaluate($rawxpath, $xmlDocument->documentElement);



        if (isset($results[(string) $xpr->length]))

                $results[(string) $xpr->length]++;

        else

                $results[(string) $xpr->length] = 1;

}



foreach ($results as $matches => $count)

        printf("In %5d instances, found $matches match(es) for
$rawxpath\n", $count);

Expected result:
----------------
In 10000 instances, found 1 match(es) for /root[1]/fie...@attr1='val1']

Actual result:
--------------
The exact numbers seem to vary, but I get roughly this response:





In  9924 instances, found 1 match(es) for /root[1]/fie...@attr1='val1']

In    76 instances, found 2 match(es) for /root[1]/fie...@attr1='val1']


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



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