AssertionError: "get_next() called when there are no chars left" in bzrlib._dirstate_helpers_pyx.Reader.get_next

Hello,

I was trying to split a bzr branch into several subbranches. I thought I'd try the answer here:

http://stackoverflow.com/questions/67021/how-do-i-export-the-bazaar-history-of-a-subfolder

in that I would use bzr split. Unfortunately, I get an error and a message to email you, which I am now doing. The crash report is attached. The branch is nothing special. The layout is

WorkDocuments/GigInvoices
WorkDocuments/SCMTalk

The command I did was in WorkDocuments, I issued "bzr split SCMTalk." If I'm doing something stupid, I apologize.

Traceback:
 Traceback (most recent call last):
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 853, in exception_to_return_code
     return the_callable(*args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1055, in run_bzr
     ret = run(*run_argv)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 661, in run_argv_aliases
     return self.run_direct(**all_cmd_args)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 665, in run_direct
     return self._operation.run_simple(*args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 122, in run_simple
     self.cleanups, self.func, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 156, in _do_with_cleanups
     result = func(*args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 4924, in run
     sub_id = containing_tree.path2id(subdir)
   File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 140, in read_locked
     result = unbound(self, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree_4.py", line 859, in path2id
     entry = self._get_entry(path=path)
   File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree_4.py", line 358, in _get_entry
     return state._get_entry(0, fileid_utf8=file_id, path_utf8=path)
   File "/usr/lib/python2.6/dist-packages/bzrlib/dirstate.py", line 1962, in _get_entry
     self._read_dirblocks_if_needed()
   File "/usr/lib/python2.6/dist-packages/bzrlib/dirstate.py", line 2202, in _read_dirblocks_if_needed
     _read_dirblocks(self)
   File "_dirstate_helpers_pyx.pyx", line 767, in bzrlib._dirstate_helpers_pyx._read_dirblocks
   File "_dirstate_helpers_pyx.pyx", line 733, in bzrlib._dirstate_helpers_pyx.Reader._parse_dirblocks
   File "_dirstate_helpers_pyx.pyx", line 654, in bzrlib._dirstate_helpers_pyx.Reader._get_entry
   File "_dirstate_helpers_pyx.pyx", line 572, in bzrlib._dirstate_helpers_pyx.Reader.get_next_str
   File "_dirstate_helpers_pyx.pyx", line 554, in bzrlib._dirstate_helpers_pyx.Reader.get_next
 AssertionError: get_next() called when there are no chars left