Python 3: Error in invoking subprocess.Popen with stream wrapper

[rgov]

I'm running Python 3.6.3 and trying to just django_gulp 3.0.0.

$ python manage.py runserver
>>> Starting gulp
<class 'django.core.management.base.OutputWrapper'> <class 'django.core.management.base.OutputWrapper'>
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/concurrent/futures/thread.py", line 56, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/Users/rzg/Projects/2017/10/cocktails-ii/.direnv/python-3.6.3/lib/python3.6/site-packages/django_gulp/management/commands/runserver.py", line 112, in start_gulp
    stderr=self.stderr)
  File "/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 667, in __init__
    errread, errwrite) = self._get_handles(stdin, stdout, stderr)
  File "/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 1184, in _get_handles
    c2pwrite = stdout.fileno()
io.UnsupportedOperation: fileno

>>> Killing pid 36211
>>> Exiting

What seems to be happening is that start_gulp calls subprocess.Popen and passes self.stdout, which is an instance of django.core.management.base.OutputWrapper. This class in turn wraps a _io.TextIOWrapper, which does not necessarily have an associated file descriptor number.

[rgov]

I'm not sure what the appropriate solution is, but for now it can just not redirect the subprocess's stdout and stderr.