bzr: ERROR: exceptions.UnboundLocalError: local variable 'revno' referenced before assignment

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 834, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 790, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools/command.py", line 13, in run_argv_aliases
    commands.Command.run_argv_aliases(self, argv, alias_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools/__init__.py", line 397, in run
    return branch_history(branch)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools/branchhistory.py", line 23, in branch_history
    print_info(descriptor, start, revno)
UnboundLocalError: local variable 'revno' referenced before assignment

bzr 1.3.1 on python 2.5.2.final.0 (linux2)
arguments: ['/usr/bin/bzr', 'branch-history', '2']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  bzrtools             /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.3.0]
  launchpad            /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
*** 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.