Dependency on 'six' and 'past' modules cause ModuleNotFoundError in a fresh Python 3(.7.3) virtualenv

[lestephane]

In a freshly created Python v3.7.3 virtualenv where I installed rubyenv using

pip install rubyenv

When running

rubyenv install 2.4.2

I get the following error

Traceback (most recent call last):
  File ".../.virtualenvs/.../bin/rubyenv", line 6, in <module>
    from rubyenv import main
  File ".../.virtualenvs/.../lib/python3.7/site-packages/rubyenv/__init__.py", line 1, in <module>
    import six
ModuleNotFoundError: No module named 'six'

Expected behaviour: pip install rubyenv should result in six being installed since it is required.

Suspected problem: the rubyenv package does not list six as a dependency / requirement even though it imports it.

[lestephane]

Tried to work around the problem with

pip install six

But then

rubyenv install 2.4.2

causes the error

Traceback (most recent call last):
  File ".../.virtualenvs/.../bin/rubyenv", line 6, in <module>
    from rubyenv import main
  File ".../.virtualenvs/.../lib/python3.7/site-packages/rubyenv/__init__.py", line 8, in <module>
    from .app import main
  File "/.../.virtualenvs/.../lib/python3.7/site-packages/rubyenv/app.py", line 13, in <module>
    from past.builtins import basestring
ModuleNotFoundError: No module named 'past'

Which can't be installed at all

$ pip install past
Collecting past
  Could not find a version that satisfies the requirement past (from versions: )
No matching distribution found for past

Not a python expert, could it be that python 3 is simply not supported?

[lestephane]

I managed to resolve the dependency on past by installing future (?)

$ pip install future

[lestephane]

So, in summary, in a fresh python 3 Virtualenv, I'd expect

$ pip install rubyenv

to result in the installation of six and future as well (if they are not installed already), because rubyenv requires them to run correctly.

[schinckel]

Yeah, those should be declared as dependencies.

[USSX-Hares]

Fixed with #6