[lxml-dev] Pb with namespaces on attributs

[Alain Poirier]

An attribut of a node, inserted then removed from a tree, can lose its 
namespace :

>>> from lxml import etree as ET
>>> parent = ET.Element('parent')
>>> parent.set('{http://foo/bar}x', 'a')
>>> child = ET.SubElement(parent, 'child')
>>> child.set('{http://foo/bar}x', 'b')

>>> print ET.tostring(child), child.nsmap
<child xmlns:ns0="http://foo/bar" ns0:x="b"/> {'ns0': 'http://foo/bar'}

>>> child = parent[0]
>>> parent.clear()
>>> print ET.tostring(child), child.nsmap
<child x="b"/> {}

It happends when the tree already knows the namespace used.

A bug in lxml or in libxml2 (tested with lxml-2.0alpha4 and libxml2 2.6.28 / 
2.6.30) ?