The error shows up on :Gundo and looks like this:
Error detected while processing function gundo#GundoShow[1]..<SNR>116_GundoShow[4]..<SNR>116_GundoOpen[31]..<SNR>116_GundoRenderPreview:
line 2:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/home/mg/.vim/bundle/Gundo/autoload/gundo.py", line 474, in GundoRenderPreview
_output_preview_text(_generate_preview_diff(current, node_before, node_after))
File "/home/mg/.vim/bundle/Gundo/autoload/gundo.py", line 382, in _generate_preview_diff
before_time, after_time))
File "/usr/lib/python3.5/difflib.py", line 1177, in unified_diff
_check_types(a, b, fromfile, tofile, fromfiledate, tofiledate, lineterm)
File "/usr/lib/python3.5/difflib.py", line 1312, in _check_types
raise TypeError('all arguments must be str, not: %r' % (arg,))
TypeError: all arguments must be str, not: 46
e5dc5f23b8