oops while logging about ratelimit

A user reported an OOPS on SSO (2306carambolaubuntu1403) on 2012-04-24.

By inspecting the oops report is shows

Traceback (most recent call last):
  Module /srv/login.ubuntu.com/production/canonical-identity-provider/identityprovider/decorators.py, line 205, in disallowed
    request.user.username, remote_ip, request.user.id)
  Module /srv/login.ubuntu.com/production/canonical-identity-provider/identityprovider/decorators.py, line 148, in view_wrapper
    return self.disallowed(request)
  Module /srv/login.ubuntu.com/production/canonical-identity-provider/identityprovider/decorators.py, line 134, in wrapper
    return self.view_wrapper(request, fn, *args, **kwargs)
  Module /usr/lib/pymodules/python2.6/django/utils/decorators.py, line 28, in _wrapper
    return bound_func(*args, **kwargs)
  Module /usr/lib/pymodules/python2.6/django/utils/decorators.py, line 24, in bound_func
    return func(self, *args2, **kwargs2)
  Module /srv/login.ubuntu.com/production/canonical-identity-provider/identityprovider/decorators.py, line 42, in _dont_cache_decorator
    response = func(request, *args, **kwargs)
  Module /usr/lib/pymodules/python2.6/django/utils/decorators.py, line 28, in _wrapper
    return bound_func(*args, **kwargs)
  Module /usr/lib/pymodules/python2.6/django/views/generic/base.py, line 47, in view
    return self.dispatch(request, *args, **kwargs)
  Module /usr/lib/pymodules/python2.6/django/core/handlers/base.py, line 111, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  Module /usr/lib/pymodules/python2.6/django/core/handlers/wsgi.py, line 273, in __call__
    response = self.get_response(request)
AttributeError: ' 'Account' object has no attribute 'username''

which indicates an error in the code handling the logging of a ratelimit-blocked post

def disallowed(self, request):
    remote_ip = self.remote_ip(request)
    logger = logging.getLogger('ratelimit.disallowed')
    logger.warn("%s (%s) exceeded rate limit for %s"
                             request.user.username, remote_ip, request.user.id)
    return HttpResponseForbidden(render_to_string('limitexceeded.html'))

request.user is an instance of Account due to the

identityprovider.middleware.useraccount.UserAccountConversionMiddleware

middleware.