Description:
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After appendChild, the namespace prefix gets lost, so it inherits the namepsace from the parent xmlns.

Reproduce code:
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// PHP 5.2.* namespace bug - appendChild() changes the namespace

$aDOM= DOMDocument::loadXML('<f2f:o xmlns:f2f=" http://friend2friend.net " xmlns:default="default"><default:i xmlns="default"><f2f:watch-me/></default:i></f2f:o>');
echo 'Initial DOM is '.$aDOM->saveXML().chr(13);

$newNode= $aDOM->createElementNS(" http://friend2friend.net ", 'newnode');
$newNode->appendChild($aDOM->documentElement);
echo 'Appending the document Element to f2f:newnode, it all looks OK: '.chr(13).$aDOM->saveXML($newNode).chr(13).chr(13);

$aDOM->appendChild($newNode);
echo 'But adding <f2f:newnode> back as the documentElement changes a namespace '.$aDOM->saveXML();

Expected result:
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Should keep the original namespace:
<newnode xmlns=" http://friend2friend.net " xmlns:default="default"><o xmlns:f2f=" http://friend2friend.net " xmlns:default="default"><default:i xmlns="default"><f2f:watch-me/></default:i></o></newnode>


Actual result:
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Loses the namespace prefix, so it inherits a different one the from xmlns of the parent node
<newnode xmlns=" http://friend2friend.net " xmlns:default="default"><o xmlns:f2f=" http://friend2friend.net " xmlns:default="default"><default:i xmlns="default"><watch-me/></default:i></o></newnode>