bzr crashed with AssertionError in _generate_inventory(): parent <email address hidden> has disappeared from ['<email address hidden>']

[Damon Lynch]

Binary package hint: bzr

I clicked the "refresh" button in bzr explorer, to refresh the diff of files prior to commit. It's never done this before.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: bzr 2.3.1-1ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
Architecture: amd64
BzrDebugFlags: set()
BzrVersion: 2.3.1
CommandLine: ['/usr/bin/bzr', 'qdiff']
CrashDb: bzr
Date: Sun Apr 10 02:32:27 2011
ExecutablePath: /usr/bin/bzr
FileSystemEncoding: UTF-8
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110202)
InterpreterPath: /usr/bin/python2.7
Locale: en_US.UTF-8
PackageArchitecture: all
Platform: Linux-2.6.38-8-generic-x86_64-with-Ubuntu-11.04-natty
ProcCmdline: /usr/bin/python /usr/bin/bzr qdiff
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonVersion: 2.7.1
SourcePackage: bzr
Title: bzr crashed with AssertionError in _generate_inventory(): parent <email address hidden> has disappeared from ['<email address hidden>']
UpgradeStatus: No upgrade log present (probably fresh install)
UserEncoding: UTF-8
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/util.py", line 884, in run_in_loading_queue
    f(*args, **kargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/diffwindow.py", line 297, in load_diff
    executable) in sorted(changes, key=changes_key):
  File "/usr/lib/python2.7/dist-packages/bzrlib/tree.py", line 1070, in iter_changes
    specific_file_ids=specific_file_ids))
  File "/usr/lib/python2.7/dist-packages/bzrlib/decorators.py", line 140, in read_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/tree.py", line 201, in iter_entries_by_dir
    return self.inventory.iter_entries_by_dir(
  File "/usr/lib/python2.7/dist-packages/bzrlib/workingtree_4.py", line 1829, in _get_inventory
    self._generate_inventory()
  File "/usr/lib/python2.7/dist-packages/bzrlib/workingtree_4.py", line 1697, in _generate_inventory
    self._revision_id, self._dirstate.get_parent_ids()))
AssertionError: parent <email address hidden> has disappeared from ['<email address hidden>']