pip --log-file does not support surrogates on Python 3

[mitsuhiko]

On Python 3 if you kick of a pip installation on a machine with an improperly set filesystem encoding and a non ASCII filename for the logfile, pip will fail:

$ pip --log-file=föo.log install wheel

Terminates with this:

Traceback (most recent call last):
  File "/home/mitsuhiko/.virtualenvs/flask-3.4/bin/pip", line 11, in <module>
    sys.exit(main())
  File "/home/mitsuhiko/.virtualenvs/flask-3.4/lib/python3.4/site-packages/pip/__init__.py", line 185, in main
    return command.main(cmd_args)
  File "/home/mitsuhiko/.virtualenvs/flask-3.4/lib/python3.4/site-packages/pip/basecommand.py", line 168, in main
    logger.fatal('Storing debug log for failure in %s' % log_file_fn)
  File "/home/mitsuhiko/.virtualenvs/flask-3.4/lib/python3.4/site-packages/pip/log.py", line 111, in fatal
    self.log(self.FATAL, msg, *args, **kw)
  File "/home/mitsuhiko/.virtualenvs/flask-3.4/lib/python3.4/site-packages/pip/log.py", line 162, in log
    consumer.write(write_content)
UnicodeEncodeError: 'ascii' codec can't encode characters in position 1-2: ordinal not in range(128)

[Ivoz]

You know how I can get this to reproduce?

 ivo·ivosung ~/.virtualenvs » mktmpenv --python=/usr/bin/python3
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in tmp-e39bdf52965272c/bin/python3
Also creating executable in tmp-e39bdf52965272c/bin/python
Installing setuptools, pip...done.
This is a temporary environment. It will be deleted when you run 'deactivate'.
 tmp-e39bdf52965272c ivo·ivosung ~/.virtualenvs/tmp-e39bdf52965272c » pip --log-file=föo.log install wheel
Downloading/unpacking wheel
  Downloading wheel-0.23.0-py2.py3-none-any.whl (61kB): 61kB downloaded
Installing collected packages: wheel
Successfully installed wheel
Cleaning up...