How to configure a package in PyPI to install only with pip3

Question

I distributed my package written in Python 3 on PyPI. It can be installed by both pip2 and pip3. How can I configure the package to only be available in Python 3; i.e. to install only with pip3?

I've already added these classifiers in setup.py file:

classifiers=[
    ...
    # Supported Python versions.
    'Programming Language :: Python :: 3',
    'Programming Language :: Python :: 3.4',
    'Programming Language :: Python :: 3.5',
    ...
]

But it still can be installed by pip2.

Answer 1

I'm not sure if such an option exists. What you could do though is manually enforce it by checking that the version of python in which it is installed is larger than the version you want to dictate:

from sys import version_info

class NotSupportedException(BaseException): pass

if version_info.major < 3:
    raise NotSupportedException("Only Python 3.x Supported")  

While this won't stop it being reached from pip2 it should stump any users trying to use an old version of Python