Use extras_require over install_requires in mypy_extensions

[sersorrel]

There are still old versions of setuptools hanging around that don't understand environment markers in install_requires (e.g. in Debian Jessie, see common-workflow-language/cwltool#872) and it would be nice if mypy_extensions would be installable on those versions of setuptools, especially since the main mypy setup.py uses extras_require for all its environment markers.

[ilevkivskyi]

LGTM!

@ethanhs are there any potential downsides/dangers? If not, then I would propose to merge this and make a point release of mypy_extensions.

[emmatyping]

I don't think there is a downside, but I also don't think it is needed if we release mypy_extensions as a wheel (which is a good thing to do in general). According to Hynek (here), only pip 1.4 is needed to install a wheel which uses install_requires. However, with a source distribution, a rather recent version of setuptools is needed to build the package. I'd prefer to release a wheel, as using extras_require in this way is not really documented.

[ilevkivskyi]

I'd prefer to release a wheel, as using extras_require in this way is not really documented.

@anowlcalledjosh Does this solution work for for you? It would be easy to just upload wheels to PyPI.

[sersorrel]

Assuming that:

only pip 1.4 is needed to install a wheel which uses install_requires

then that sounds fine to me - I have no desire to perpetuate the extras_require hack if it's not necessary.

[ilevkivskyi]

OK, I will make micro-release mypy_extensions 0.4.1 now.

[ilevkivskyi]

OK, I just uploaded the source and wheels distributions for mypy_extensions 0.4.1.

Closing this for now. Please re-open or create a new issue if you still have problems.

[ilevkivskyi]

FYI https://pypi.org/project/mypy_extensions/0.4.1/#files