pypa/virtualenv — pull request #280 by raulgrell (2012-05-23 06:18:52+00:00)
Title: Fixing bytes/str mismatch in create_bootstrap_script()

Essentially, the virtualenv.py file was being read in byte mode. These bytes were then joined to strings, resulting in a type error, https://github.com/pypa/virtualenv/issues/279

It has been repeatedly drummed into my head that opening a file without specifying its encoding is a bad idea, so instead of just removing the b flag, i opted to interface with the files using the codecs module.