Crash after update on empty branch with merge

[Michiel Uitdehaag]

Traceback:
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
bzr 2.2.4 on python 2.6.6 (Linux-2.6.35-30-generic-x86_64-with-Ubuntu-10.10-maverick)

Situation:
I have a init-repo repositorie with --no-trees on the server
In that repository I have a branch 'test' with several commits and a branch 'production' without commits.
I checked out (co) the production branch, merged with a revision (not top) of the test branch.
bzr stat reported the tree was out of sync
bzr update crashes with the above message.

I then checked out the production branch elsewhere, committed an empty first revision (--unchanged).
In the first checkout, I did a bzr update which succeeded now. bzr stat also did not report the tree was out of sync.

[Martin Pool (mbp)]

I believe this is fixed in bzr 2.4, which is available for maverick from http://pad.lv/ppa/bzr