Comment 4 for bug 898806

I can confirm the issue on Ubuntu 12.04, using the following bzr version (to make it work with git-bzr-ng): https://code.launchpad.net/~larstiq/bzr/bug541626, and bzr-fastimport 0.13.0-1 (which is the trunk I believe).

$ bzr --version
Bazaar (bzr) 2.6.0dev2
  from bzr checkout /home/fr710/src/bzr
    revision: 6524
    revid: <email address hidden>
    branch nick: bzr
  Python interpreter: /usr/bin/python 2.7.3
  Python standard library: /usr/lib/python2.7
  Platform: Linux-3.2.0-24-generic-x86_64-with-Ubuntu-12.04-precise

Backtrace:

  File "/home/fr710/src/bzr/bzrlib/commands.py", line 930, in exception_to_retur
n_code
    return the_callable(*args, **kwargs)
  File "/home/fr710/src/bzr/bzrlib/commands.py", line 1141, in run_bzr
    ret = run(*run_argv)
  File "/home/fr710/src/bzr/bzrlib/commands.py", line 673, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/fr710/src/bzr/bzrlib/commands.py", line 697, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/home/fr710/src/bzr/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/home/fr710/src/bzr/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/cmds.py", lin
e 307, in run
    user_map=user_map)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/cmds.py", lin
e 39, in _run
    return proc.process(p.iter_commands)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/processors/ge
neric_processor.py", line 310, in process
    super(GenericProcessor, self)._process(command_iter)
  File "/usr/lib/python2.7/dist-packages/fastimport/processor.py", line 75, in _
process
    handler(self, cmd)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/processors/ge
neric_processor.py", line 535, in commit_handler
    handler.process()
  File "/usr/lib/python2.7/dist-packages/fastimport/processor.py", line 158, in
process
    self.post_process_files()
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/bzr_commit_ha
ndler.py", line 672, in post_process_files
    self._get_inventories)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/revision_stor
e.py", line 400, in load_using_delta
    tree, basis_rev_id, changes):
  File "/home/fr710/src/bzr/bzrlib/vf_repository.py", line 705, in record_iter_c
hanges
    head_set = self._heads(change[0], set(head_candidates))
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/fastimport/revision_stor
e.py", line 387, in thunked_heads
    res = set(self._graph.heads(revision_ids))
  File "/home/fr710/src/bzr/bzrlib/graph.py", line 1697, in heads
    head_keys = self._graph.heads(as_keys)
  File "_known_graph_pyx.pyx", line 444, in bzrlib._known_graph_pyx.KnownGraph.h
eads (bzrlib/_known_graph_pyx.c:4217)
KeyError: "key ('xxx',) not in nodes"

The suggested workaround has worked for my case.