Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

I double checked documentation, node corruption is not mentioned there.

if the return value of removeChild is assigned to a variable,
everything works as expected:
-----------------8<---------------
$dom = DOMDocument::loadXML('<root><child/></root>');
$xpath = new DOMXpath($dom);
$node = $xpath->query('//child')->item(0);
echo $node->nodeName . "\n";
$res = $GLOBALS['dom']->removeChild($GLOBALS['dom']->firstChild);

echo "nodeType: " . $node->nodeType . "\n";
echo "nodeName: " .$node->nodeName . "\n";
echo "parentNode: " .$node->parentNode . "\n";
---------------->8--------------------

if the return value is ignored:
----------------------------8<---------------
$dom = DOMDocument::loadXML('<root><child/></root>');
$xpath = new DOMXpath($dom);
$node = $xpath->query('//child')->item(0);
echo $node->nodeName . "\n";
$GLOBALS['dom']->removeChild($GLOBALS['dom']->firstChild);

echo "nodeType: " . $node->nodeType . "\n";
echo "nodeName: " .$node->nodeName . "\n";
echo "parentNode: " .$node->parentNode . "\n";
-------------------------->8------------

or goes out of scope:
--------------------8<-----------
$dom = DOMDocument::loadXML('<root><child/></root>');
$xpath = new DOMXpath($dom);
$node = $xpath->query('/root/child')->item(0);
echo $node->nodeName;
function test()
{
    $x = $GLOBALS['dom']->removeChild($GLOBALS['dom']->firstChild);
}
test();
echo $node->nodeName;
-------------------->8-----------

$node gets corrupted.

Assigning to self. Node is not corrupted. It just doesn't exist. Try calling $node->hasChildNodes() and you will see the warning. I'll look at adding a warning when accessing properties in this case.

Behavior will not change. When subtree is unlinked and root of subtree is not referenced entire subtree is released to avoid memory issues. Changing this would slow down all tree based extensions (dom, simplexml and xsl) drastically, so always reference the detached tree's root if you want to use it again.

This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.

Warning has been added when node no longer exists and property is accessed.