With bzr+http it looks like this, showing my changes are not yet enough, and that Google is not having such a bad day as yesterday.

(I'm posting them here for later reference because of the intermittent failures.)

0.682  > POST /hg/.bzr/smart
0.682  > Content-Length: 6
> Connection: Keep-Alive
> Accept: */*
> User-Agent: bzr/2.1.0dev5 (urllib)
> Host: spyderlib.googlecode.com
> Pragma: no-cache
> Cache-Control: max-age=0
> Content-Type: application/x-www-form-urlencoded

0.986  < HTTP/1.1 405 Method Not Allowed
0.986  < Content-Type: text/html; charset=UTF-8
< Allow: GET, HEAD
< Date: Thu, 17 Dec 2009 05:29:16 GMT
< Server: hg_frontend
< Content-Length: 1404
< X-XSS-Protection: 0

0.988  hpss call:   'get', '.bzr/branch-format'
0.988               (to http://spyderlib.googlecode.com/hg/)
0.989  * About to connect() to spyderlib.googlecode.com:80
1.041  > POST /hg/.bzr/smart
1.041  > Content-Length: 94
> Connection: Keep-Alive
> Accept: */*
> User-Agent: bzr/2.1.0dev5 (urllib)
> Host: spyderlib.googlecode.com
> Pragma: no-cache
> Cache-Control: max-age=0
> Content-Type: application/x-www-form-urlencoded

1.346  < HTTP/1.1 405 Method Not Allowed
1.346  < Content-Type: text/html; charset=UTF-8
< Allow: GET, HEAD
< Date: Thu, 17 Dec 2009 05:29:16 GMT
< Server: hg_frontend
< Content-Length: 1404
< X-XSS-Protection: 0

1.424  Traceback (most recent call last):
  File "/home/mbp/bzr/497274-http-405/bzrlib/commands.py", line 826, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/home/mbp/bzr/497274-http-405/bzrlib/commands.py", line 1027, in run_bzr
    ret = run(*run_argv)
  File "/home/mbp/bzr/497274-http-405/bzrlib/commands.py", line 638, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/mbp/bzr/497274-http-405/bzrlib/commands.py", line 1042, in ignore_pipe
    result = func(*args, **kwargs)
  File "/home/mbp/bzr/497274-http-405/bzrlib/builtins.py", line 2316, in run
    revision, file_list)
  File "/home/mbp/bzr/497274-http-405/bzrlib/log.py", line 1897, in _get_info_for_log_files
    tree, b, path = bzrdir.BzrDir.open_containing_tree_or_branch(file_list[0])
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 971, in open_containing_tree_or_branch
    bzrdir, relpath = klass.open_containing(location)
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 898, in open_containing
    return BzrDir.open_containing_from_transport(transport)
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 919, in open_containing_from_transport
    result = BzrDir.open_from_transport(a_transport)
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 873, in open_from_transport
    redirected)
  File "/home/mbp/bzr/497274-http-405/bzrlib/lazy_import.py", line 125, in __call__
    return obj(*args, **kwargs)
  File "/home/mbp/bzr/497274-http-405/bzrlib/transport/__init__.py", line 1644, in do_catching_redirections
    return action(transport)
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 860, in find_format
    transport, _server_formats=_server_formats)
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 1820, in find_format
    return format.probe_transport(transport)
  File "/home/mbp/bzr/497274-http-405/bzrlib/bzrdir.py", line 1830, in probe_transport
    format_string = transport.get_bytes(".bzr/branch-format")
  File "/home/mbp/bzr/497274-http-405/bzrlib/transport/remote.py", line 226, in get_bytes
    resp, response_handler = self._client.call_expecting_body('get', remote)
  File "/home/mbp/bzr/497274-http-405/bzrlib/smart/client.py", line 142, in call_expecting_body
    method, args, expect_response_body=True)
  File "/home/mbp/bzr/497274-http-405/bzrlib/smart/client.py", line 87, in _call_and_read_response
    readv_body=readv_body, body_stream=body_stream)
  File "/home/mbp/bzr/497274-http-405/bzrlib/smart/client.py", line 60, in _send_request
    encoder.call(method, *args)
  File "/home/mbp/bzr/497274-http-405/bzrlib/smart/protocol.py", line 1298, in call
    self._medium_request.finished_writing()
  File "/home/mbp/bzr/497274-http-405/bzrlib/smart/medium.py", line 441, in finished_writing
    self._finished_writing()
  File "/home/mbp/bzr/497274-http-405/bzrlib/transport/http/__init__.py", line 694, in _finished_writing
    data = self._medium.send_http_smart_request(self._buffer)
  File "/home/mbp/bzr/497274-http-405/bzrlib/transport/http/__init__.py", line 669, in send_http_smart_request
    raise errors.SmartProtocolError(str(e))
SmartProtocolError: Generic bzr smart protocol error: Invalid http response for http://spyderlib.googlecode.com/hg/.bzr/smart: Unable to handle http code 405: Method Not Allowed