Comment 3 for bug 527043

Interesting solution, but I do not know if the file _version.py created by
bzr version-info --python
is updated automatically (without the need to re-run the brz version-info command after each commit).

The clean attribute can indeed be useful to determine whether or not the working tree is up-to-date.
http://doc.bazaar.canonical.com/latest/en/user-guide/version_info.html