bzrlib.errors.ObjectNotLocked annotating file from other branch

Steps to reproduce:
$ bzr init-repo repo
$ cd repo
$ bzr init trunk
$ cd trunk
$ echo foo > foo
$ bzr add foo
$ bzr ci -m foo
$ cd ..
$ bzr co --lightweight trunk work
$ cd work
$ bzr --no-plugins annotate -r branch:../trunk foo

bzr: ERROR: bzrlib.errors.ObjectNotLocked: <bzrlib.groupcompress._GCGraphIndex object at 0x1f7c250> is not locked

Traceback (most recent call last):
  File ".../bzr.dev/bzrlib/commands.py", line 826, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File ".../bzr.dev/bzrlib/commands.py", line 1027, in run_bzr
    ret = run(*run_argv)
  File ".../bzr.dev/bzrlib/commands.py", line 638, in run_argv_aliases
    return self.run(**all_cmd_args)
  File ".../bzr.dev/bzrlib/commands.py", line 1042, in ignore_pipe
    result = func(*args, **kwargs)
  File ".../bzr.dev/bzrlib/builtins.py", line 4512, in run
    file_version = tree.inventory[file_id].revision
  File ".../bzr.dev/bzrlib/inventory.py", line 2016, in __getitem__
    self.id_to_entry.iteritems([StaticTuple(file_id,)]).next()[1])
  File ".../bzr.dev/bzrlib/chk_map.py", line 494, in iteritems
    self._ensure_root()
  File ".../bzr.dev/bzrlib/chk_map.py", line 143, in _ensure_root
    self._root_node = self._get_node(self._root_node)
  File ".../bzr.dev/bzrlib/chk_map.py", line 156, in _get_node
    bytes = self._read_bytes(node)
  File ".../bzr.dev/bzrlib/chk_map.py", line 167, in _read_bytes
    bytes = stream.next().get_bytes_as('fulltext')
  File ".../bzr.dev/bzrlib/groupcompress.py", line 1413, in get_record_stream
    orig_keys, ordering, include_delta_closure):
  File ".../bzr.dev/bzrlib/groupcompress.py", line 1518, in _get_remaining_record_stream
    locations = self._index.get_build_details(keys)
  File ".../bzr.dev/bzrlib/groupcompress.py", line 2003, in get_build_details
    self._check_read()
  File ".../bzr.dev/bzrlib/groupcompress.py", line 1923, in _check_read
    raise errors.ObjectNotLocked(self)
ObjectNotLocked: <bzrlib.groupcompress._GCGraphIndex object at 0x1f7c250> is not locked

bzr 2.1.0dev4 on python 2.6.4 (Linux-2.6.32-gentoo-x86_64-AMD_Phenom-tm-_II_X4_945_Processor-with-gentoo-2.0.1)
arguments: ['.../bzr.dev/bzr', '--no-plugins', 'annotate', '-r', 'branch:../trunk', 'foo']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'de_DE.utf8'
plugins:

*** 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.

This happened with current bzr.dev, i.e. 4894 resp. <email address hidden>