bzr update ERROR: exceptions.TypeError: must be string or read-only buffer, not None

[Thomas Vqd]

bzr: ERROR: exceptions.TypeError: must be string or read-only buffer, not None

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 920, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1131, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 673, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 695, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/builtins.py", line 1780, in run
    show_base=show_base)
  File "/usr/lib/python2.7/dist-packages/bzrlib/workingtree.py", line 1435, in update
    return self._update_tree(old_tip, change_reporter, revision, show_base)
  File "/usr/lib/python2.7/dist-packages/bzrlib/mutabletree.py", line 52, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/workingtree.py", line 1505, in _update_tree
    show_base=show_base)
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 2021, in merge_inner
    return merger.do_merge()
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 686, in do_merge
    merge = operation.run_simple()
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 654, in _do_merge_to
    merge.do_merge()
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 802, in do_merge
    operation.run()
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 132, in run
    self.cleanups, self.func, self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 807, in _do_merge
    self._compute_transform()
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 857, in _compute_transform
    self._finish_computing_transform()
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 867, in _finish_computing_transform
    lambda t, c: transform.conflict_pass(t, c, self.other_tree))
  File "/usr/lib/python2.7/dist-packages/bzrlib/transform.py", line 3032, in resolve_conflicts
    new_conflicts.update(pass_func(tt, conflicts))
  File "/usr/lib/python2.7/dist-packages/bzrlib/merge.py", line 867, in <lambda>
    lambda t, c: transform.conflict_pass(t, c, self.other_tree))
  File "/usr/lib/python2.7/dist-packages/bzrlib/transform.py", line 3127, in conflict_pass
    if path_tree and path_tree.has_id(file_id):
  File "/usr/lib/python2.7/dist-packages/bzrlib/tree.py", line 790, in has_id
    return self.inventory.has_id(file_id)
  File "/usr/lib/python2.7/dist-packages/bzrlib/inventory.py", line 1939, in has_id
    self.id_to_entry.iteritems([StaticTuple(file_id,)]))) == 1
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 1049, in iteritems
    for node, node_filter in self._iter_nodes(store, key_filter=key_filter):
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 1099, in _iter_nodes
    search_prefix = self._search_prefix_filter(key)
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 1335, in _search_prefix_filter
    return self._search_key_func(key)[:self._node_width]
  File "_chk_map_pyx.pyx", line 143, in bzrlib._chk_map_pyx._search_key_255
TypeError: must be string or read-only buffer, not None

bzr 2.5.1 on python 2.7.3 (Linux-3.2.0-91-generic-x86_64-with-
    Ubuntu-12.04-precise)
arguments: ['/usr/bin/bzr', 'update']
plugins: bash_completion[2.5.1], changelog_merge[2.5.1], launchpad[2.5.1],
    netrc_credential_store[2.5.1], news_merge[2.5.1], po_merge[2.5.1],
    qbzr[0.22.2], weave_fmt[2.5.1]
encoding: 'ascii', fsenc: 'utf8', lang: 'POSIX'

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem.

Here it is...