Feature request: Do not build wheels for python versions not supported by package

[clbarnes]

My computer has more versions of python installed on it than my pyo3-based library supports. maturin build should not build wheels for unsupported python versions. Of course, it's possible to specify exactly which versions to build on every call to maturin build, but that's a relatively static item of metadata which is a good fit for a config file (probably the Cargo.toml, although possibly pyproject.toml).

One option would be to parse the trove classifiers specified in package.metadata.maturin.classifier package.metadata.maturin.requires-python, and build wheels for the intersection of what maturin supports and what is specified there.

[konstin]

What operating system are you using and what are those python versions? For unix system, maturin has a predefined list it checks, and for windows, it's using py -0 and picks only python3 versions.

[clbarnes]

Using ubuntu, I have pythons 2.7, 3.4, 3.5, 3.6, and 3.7. My package only supports 3.6 and 3.7. Maturin ignores 2.7 and 3.4, as it should, but still creates a wheel for 3.5.

[konstin]

Thanks for the clarification, I see now. It should definitely be supported to restrict the python through some metadata key.