Comment 1 for bug 588060

From some experimenting, I was able to isolate this cause for me:

<mtaylor> lifeless: I figured out the cause at least - in the tree I had moved a file, license.py, to internal/licensing.py and then added a new file called license.py
<mtaylor> lifeless: this caused merge upstream to become confused
<mtaylor> lifeless: if I re-expressed that in the upstream bzr tree as adding a new file internal/licesnsing.py and modifying license.py with the new contents - all worked fine

So I'm guessing it has to do with move/rename tracking and tarball importing perhaps.