Comment 3 for bug 446033

Not surprisingly it looks like we're getting None when we should get a stat value. This might be because of a race where a file (maybe an editor lock or backup) appears and then disappears in the tree while it's being read.

 Traceback (most recent call last):
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 842, in exception_to_return_code
     return the_callable(*args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1037, in run_bzr
     ret = run(*run_argv)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 654, in run_argv_aliases
     return self.run(**all_cmd_args)
   File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 3051, in run
     exclude=safe_relpath_files(tree, exclude))
   File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 192, in write_locked
     result = unbound(self, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree_4.py", line 197, in commit
     result = WorkingTree3.commit(self, message, revprops, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 192, in write_locked
     result = unbound(self, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/mutabletree.py", line 228, in commit
     *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commit.py", line 360, in commit
     self._update_builder_with_changes()
   File "/usr/lib/python2.6/dist-packages/bzrlib/commit.py", line 633, in _update_builder_with_changes
     self.work_tree, self.basis_revid, iter_changes):
   File "/usr/lib/python2.6/dist-packages/bzrlib/repository.py", line 636, in record_iter_changes
     for change in iter_changes:
   File "/usr/lib/python2.6/dist-packages/bzrlib/commit.py", line 654, in _filter_iter_changes
     for change in iter_changes:
   File "_dirstate_helpers_pyx.pyx", line 1405, in _dirstate_helpers_pyx.ProcessEntryC.__next__
   File "_dirstate_helpers_pyx.pyx", line 1678, in _dirstate_helpers_pyx.ProcessEntryC._iter_next
   File "_dirstate_helpers_pyx.pyx", line 1847, in _dirstate_helpers_pyx.ProcessEntryC._loop_one_block
   File "/usr/lib/python2.6/dist-packages/bzrlib/osutils.py", line 1485, in _walkdirs_utf8
     dirblock = sorted(read_dir(relroot, top))
   File "_readdir_pyx.pyx", line 257, in _readdir_pyx.UTF8DirReader.read_dir