Here's a repo that reproduces the error: https://github.com/petertodd/gitpython-unicode-error

The filename in question is 'v\udcbb', and print('v\udcbb') raises "UnicodeEncodeError: 'utf-8' codec can't encode character '\udcbb' in position 1: surrogates not allowed", so likely there's some kind of unicode-related problem here.