StopIteration in set_state_from_inventory

Running 'bzr repair-workingtree -force' in a branch that's never been committed to fails like so:

mbp@joy% bzr repair-workingtree --force
bzr: ERROR: exceptions.StopIteration:

Traceback (most recent call last):
  File "/home/mbp/bzr/trunk/bzrlib/commands.py", line 923, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/home/mbp/bzr/trunk/bzrlib/commands.py", line 1123, in run_bzr
    ret = run(*run_argv)
  File "/home/mbp/bzr/trunk/bzrlib/commands.py", line 688, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/mbp/bzr/trunk/bzrlib/commands.py", line 710, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/home/mbp/bzr/trunk/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/home/mbp/bzr/trunk/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/home/mbp/bzr/trunk/bzrlib/builtins.py", line 530, in run
    tree.reset_state(revision_ids)
  File "/home/mbp/bzr/trunk/bzrlib/mutabletree.py", line 49, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/home/mbp/bzr/trunk/bzrlib/workingtree_4.py", line 1311, in reset_state
    state.set_state_from_scratch(base_tree.inventory, trees, [])
  File "/home/mbp/bzr/trunk/bzrlib/dirstate.py", line 2709, in set_state_from_scratch
    self.set_state_from_inventory(working_inv)
  File "/home/mbp/bzr/trunk/bzrlib/dirstate.py", line 2594, in set_state_from_inventory
    current_new = new_iterator.next()
StopIteration