exarkun@boson:~/Projects/bullet/trunk$ bzr merge ../branches/extract-from-game/
+N  bullet/
+N  bullet/__init__.py
+N  bullet/bullet.pyx
+N  bullet/memory.py
+N  bullet/test_bullet.py
+N  demos/
+N  demos/helloworld.py
+N  setup.py
All changes applied successfully.
exarkun@boson:~/Projects/bullet/trunk$ bzr st
bworking tree is out of date, run 'bzr update'
renamed:
  bullet/ => bullet/
  demos/ => demos/
  setup.py => setup.py
exarkun@boson:~/Projects/bullet/trunk$ bzr qlog
exarkun@boson:~/Projects/bullet/trunk$ ls
bullet  demos  setup.py
exarkun@boson:~/Projects/bullet/trunk$ bzr revert
-   /
R   bullet/ => bullet/
R   demos/ => demos/
R   setup.py => setup.py
exarkun@boson:~/Projects/bullet/trunk$ ls
bullet  demos  setup.py
exarkun@boson:~/Projects/bullet/trunk$ bzr st
working tree is out of date, run 'bzr update'
exarkun@boson:~/Projects/bullet/trunk$ bzr update
bzr: ERROR: exceptions.ValueError: WorkingTree.set_root_id with fileid=None

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 912, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1112, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 690, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 705, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 1440, in run
    old_tip=old_tip)
  File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree.py", line 2262, in update
    return self._update_tree(old_tip, change_reporter, revision)
  File "/usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree.py", line 2317, in _update_tree
    self.set_root_id(to_root_id)
  File "/usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py", line 50, in tree_write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree.py", line 2175, in set_root_id
    'WorkingTree.set_root_id with fileid=None')
ValueError: WorkingTree.set_root_id with fileid=None

You can report this problem to Bazaar's developers by running
    apport-bug /var/crash/bzr.1000.2010-12-19T17:04.crash
if a bug-reporting window does not automatically appear.
e