def __getattr__(self, attr):
        # XXX this is a fallback mechanism to guard against these
        # methods getting called in a non-standard order.  this may be
        # too complicated and/or unnecessary.
        # XXX should the __r_XXX attributes be public?
        if attr[:12] == '_Request__r_':
            name = attr[12:]
            if hasattr(Request, 'get_' + name):
                getattr(self, 'get_' + name)()
                return getattr(self, attr)
        raise AttributeError, attr

this may cause "maximum recursion depth exceeded"

>>> import urllib2
>>> req = urllib2.Request('http://www.nbc.com')
>>> req._Request__r_method
RuntimeError: maximum recursion depth exceeded

"return getattr(self, attr)"? should it be removed?

That __getattr__ was removed in r70815 and in Python 3.1 it's OK.
The change wasn't backported to the trunk though.

Assigning to Jeremy to see what he thinks about it.