Hi,

using an absolute ObjectPath with a wrong root element

objectify.ObjectPath("wrongroot.a.b")(root, None) currently raises ValueError

even if a default is given:

>>> root = objectify.fromstring("<root><a><b>23</b></a></root>")
>>> objectify.ObjectPath("root.a.b")(root, None)
23
>>> objectify.ObjectPath("wrongroot.a.b")(root, None)
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "objectpath.pxi", line 53, in lxml.objectify.ObjectPath.__call__
  File "objectpath.pxi", line 197, in lxml.objectify._findObjectPath
ValueError: root element does not match: need wrongroot, got root
>>>

Whereas ObjectPath returns a given default if any other

element of the path is not in the tree:

>>> objectify.ObjectPath("root.wronga.b")(root, None)
>>>

I'll change this in trunk to gracefully return the default, and add some tests

(unless someone stops me... :)

Holger