"exceptions.ValueError: get_parent_map(None) is not valid" in before:$invalid_dotted_revno

More specifically:

mwh@grond:~/canonical/repos/loggerhead/trunk$ bzr.dev revision-info -r before:11111111111111.111111111111111
bzr: ERROR: exceptions.ValueError: get_parent_map(None) is not valid

Traceback (most recent call last):
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/commands.py", line 846, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/commands.py", line 797, in run_bzr
    ret = run(*run_argv)
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/commands.py", line 499, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/commands.py", line 807, in ignore_pipe
    result = func(*args, **kwargs)
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/builtins.py", line 287, in run
    revision_id = rev.as_revision_id(b)
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/revisionspec.py", line 245, in as_revision_id
    return self._as_revision_id(context_branch)
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/revisionspec.py", line 530, in _as_revision_id
    parent_map = context_repo.get_parent_map([base_revision_id])
  File "/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/repofmt/pack_repo.py", line 1925, in get_parent_map
    raise ValueError('get_parent_map(None) is not valid')
ValueError: get_parent_map(None) is not valid

bzr 1.6b3 on python 2.5.2 (linux2)
arguments: ['/home/mwh/canonical/repos/bzr/bzr.dev/bzr', 'revision-info', '-r', 'before:11111111111111.111111111111111']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_NZ.UTF-8'
plugins:
  bpm /home/mwh/.bazaar/plugins/bpm [unknown]
  bzrtools /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.5.0]
  gtk /home/mwh/.bazaar/plugins/gtk [0.95.0dev1]
  launchpad /home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/plugins/launchpad [unknown]
  lpreview /home/mwh/.bazaar/plugins/lpreview [unknown]
  pqm /home/mwh/.bazaar/plugins/pqm [1.4.0dev0]
  search /home/mwh/.bazaar/plugins/search [1.6.0dev0]
  svn /home/mwh/.bazaar/plugins/svn [0.4.11dev0]
*** Bazaar has encountered an internal error.
    Please report a bug at https://bugs.launchpad.net/bzr/+filebug
    including this traceback, and a description of what you
    were doing when the error occurred.

(this is loggerhead trunk, lp:loggerhead, but I hardly believe that matters)

This is probably not entirely unrelated:

mwh@grond:~/canonical/repos/loggerhead/trunk$ bzr.dev revision-info -r 11111111111111.111111111111111
/home/mwh/canonical/repos/bzr/bzr.dev/bzrlib/branch.py:512: DeprecationWarning: NULL_REVISION should be used for the null revision instead of None, as of bzr 0.90.
  if _mod_revision.is_null(revision_id):
   0 None

(the above is with bzr.dev 3495)