Branching over bzr+http fails with AttributeError

When branching using a HTTP transport to a smart server (bzr+http:// URL scheme) fails. The smart server configured at the server used below uses Apache + mod_wsgi + bzr-1.1; but the bug seems to be in the client part as no errors are shown in the Apache error_log.

I had some chat at #bzr in Freenode with james_w and poolie I tested the same bzr-1.3rc1, which fixed the problem. I am reporting the bug here for the sake of documentation.

Traceback for bzr-1.2 follows.

$ ./bzr branch bzr+http://code.connectical.com/overlay/bzr/trunk testbranch
bzr: ERROR: exceptions.AttributeError: 'HttpTransport_urllib' object has no attribute '_remote_is_at_least_1_2'

Traceback (most recent call last):
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/commands.py", line 834, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/commands.py", line 790, in run_bzr
    ret = run(*run_argv)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/builtins.py", line 908, in run
    accelerator_tree=accelerator_tree)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/bzrdir.py", line 939, in sprout
    revision_id=revision_id)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/remote.py", line 641, in sprout
    dest_repo.fetch(self, revision_id=revision_id)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/repository.py", line 949, in fetch
    return inter.fetch(revision_id=revision_id, pb=pb, find_ghosts=find_ghosts)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/decorators.py", line 165, in write_locked
    return unbound(self, *args, **kwargs)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/repository.py", line 2930, in fetch
    pb=pb, find_ghosts=find_ghosts)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/fetch.py", line 109, in __init__
    self.__fetch()
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/fetch.py", line 135, in __fetch
    search = self._revids_to_fetch()
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/fetch.py", line 208, in _revids_to_fetch
    find_ghosts=self.find_ghosts)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/decorators.py", line 127, in read_locked
    return unbound(self, *args, **kwargs)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/repository.py", line 871, in search_missing_revision_ids
    revision_id, find_ghosts)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/decorators.py", line 127, in read_locked
    return unbound(self, *args, **kwargs)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/repository.py", line 2412, in search_missing_revision_ids
    return self._walk_to_common_revisions([revision_id])
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/repository.py", line 2366, in _walk_to_common_revisions
    next_revs, ghosts = searcher.next_with_ghosts()
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/graph.py", line 572, in next_with_ghosts
    self._advance()
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/graph.py", line 582, in _advance
    found, ghosts, next, parents = self._do_query(self._next_query)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/graph.py", line 605, in _do_query
    parent_map = self._parents_provider.get_parent_map(revisions)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/remote.py", line 787, in get_parent_map
    parent_map = self._get_parent_map(missing_revisions)
  File "/home/acastro/Desktop/bzr-1.2/bzrlib/remote.py", line 821, in _get_parent_map
    if not medium._remote_is_at_least_1_2:
AttributeError: 'HttpTransport_urllib' object has no attribute '_remote_is_at_least_1_2'

bzr 1.2.0 on python 2.5.1.final.0 (linux2)
arguments: ['./bzr', 'branch', 'bzr+http://code.connectical.com/overlay/bzr/trunk', 'testbranch']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  launchpad /home/acastro/Desktop/bzr-1.2/bzrlib/plugins/launchpad [unknown]