This regexp doesn't seem to work in all cases.  My `bzr info` output looks like this:

  Repository checkout (format: 2a)
  Location:
    repository checkout root: .
          checkout of branch: bzr+ssh://server/db/repo/trunk/
           shared repository: /home/julian/source/repo

  Related branches:
    submit branch: /home/julian/source/repo/branches/stage1

Thanks for doing this, I've got your code working on windows 7 with bzr 2.2.0, but I had to do two little hacks to get it to work.

Had to change the regex to
BRANCH_REGEX = r'\w*(branch|branch root): (?P<branch_path>.+)$' 
to get it to work in my case. 

The output of bzr info was:
Repository checkout (format: 2a)
Location:
  repository checkout root: .
        checkout of branch: bzr://<my_remote_repo>
         shared repository: C:/<my_local_folder>

I don't think this work if you're in a repo without a branch.