How do I build a py2 wheel package, when setup.py runs with a Python version 3 interpreter?

Question

I have a package that is supposed to be Python version 2 only but needs to be build running a version 3 interpreter.

The setup.py of this package looks something like hits:

from setuptools import setup

setup(
    python_requires="<3.0, >=2.7.5",
    classifiers=[
        'Programming Language :: Python :: 2',
        'Intended Audience :: Developers',
    ],
    # ... more keyword arguments ... 
 )

If I call python2 setup.py build bdist_wheel, I get:

$ ls dist
mypackage-0.3.dev14-py2-none-any.whl

If I run it with a version 3 interpreter, i.e. python3 setup.py build bdist_wheel, I get:

$ ls dist
mypackage-0.3.dev14-py3-none-any.whl

I would have expected that regardless of the interpreter version, I will get a py2 package, because I specified it with python_requires (and in the tags). My package build server only has a Python 3 interpreter.

How can I build a wheel that targets Python 2 when running setuptools with a Python 3 interpreter? Is that at all possible? Does the -py3-/-py2 in the filename mean something different than I think it does?

Answer 1

Try passing the python-tag argument to bdist_wheel:

python setup.py bdist_wheel --python-tag=py2

It could also be passed as

from setuptools import setup
setup(options={'bdist_wheel':{'python_tag':'py2'}})

Or in setup.cfg