Add a (potentially temporary) py.typed file?

[person142]

This came up in #11936 (comment).

As of right now type checkers would ignore an installed version of SciPy because we don't have a py.typed file per PEP 561:

https://www.python.org/dev/peps/pep-0561/#packaging-type-information

This makes it harder for downstream projects that want to test out the types we are adding. What do people think about adding that py.typed file now so that people can try the types out, and then removing for the next release if the types aren't ready? (Though I hope at least a rudimentary form of them will be.)

This might mean that downstream experimenters have to ignore some errors in their configs, but that seems like a reasonable trade-off.

[person142]

Note that the py.typed file doesn't contain anything fancy-it's just an empty file that serves as a marker.

[rgommers]

Seems reasonable. I can't think of something that will break and can't be easily fixed by copying the ignores we have in our mypy.ini.

[person142]

Ping @rth: if you want to test things against the SciPy stubs, now you just:

• Install the mypy_requirements.txt
• Install SciPy from master