We know, I left it there to help MvL debug the issues in the diff generator.

The version I created with the rdiff extension is correct though, and Martin fixed the Reitveld integration to handle the extra lines at the start of the diff.

I wouldn't actually commit the change as it stands (if nothing else, PyErr_Matches() calls are needed in the unicode methods), but it gives a clear idea of the magnitude of the changes needed.