Specifying additional dependencies in setup.py script based on implementation (PyPy / CPython support)

Question

Preface

I have a package with PyPy support and for CPython users it has mypy as an additional dependency which I specify as

import platform

from setuptools import setup
...
install_requires = [...]
if platform.python_implementation() != 'PyPy':
    install_requires.append('mypy>=0.630')
setup(...,
      install_requires=install_requires)

and locally it works fine, but when I create source distribution via CPython like

> python setup.py sdist

and try to install it via PyPy

> pypy3 -m pip install path/to/package.tar.gz

it tries to install mypy (and fails since mypy uses CPython-specific packages), so it looks like dependencies are taken for CPython version (for which distribution was created).

Problem

How can I specify dependencies and create source distribution once so it will work for both CPython & PyPy versions (and upload to PyPI afterwards)?

user_3545273 · Answer

Your current script tests the platform at build time, and not at install time.

What you need to use is not the platform module, but environment markers defined in PEP 508:

from setuptools import setup
...
install_requires = [...,
                    'mypy>=0.630; implementation_name != "PyPy"']
setup(...,
      install_requires=install_requires)

References:

Specifying additional dependencies in setup.py script based on implementation (PyPy / CPython support)

Preface

Problem

1 Answers