Add requires-python metadata to avoid broken installs

[matthewfeickert]

Release v0.7 notes that

Python versions prior to 3.10 are not supported anymore.

and mentions this in the README

rundec-python/README.md

Line 61 in 279cd35

Python 3.10+ is supported.

However, setup.py is missing requires-python metadata, which means that pip or uv with CPython older than Python 3.10 will still try to install v0.7+ and may fail if they do not have the required build tools on the install machine.

For setuptools the requires-python metadata is expressed through the arg python_requires to setup. So please add

python_requires='>=3.10'

to setup.py and please yank v0.7 from PyPI and do not release v0.7.1 to PyPI.

[matthewfeickert]

Example:

$ docker run --rm -ti ghcr.io/prefix-dev/pixi:latest
# pixi global install uv
└── uv: 0.9.10 (installed)
    └─ exposes: uv, uvx
# uv venv --python 3.9
Using CPython 3.9.25
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate
# . .venv/bin/activate
# uv pip install rundec
Resolved 1 package in 329ms
  x Failed to build `rundec==0.7`
  |-> The build backend returned an error
  `-> Call to `setuptools.build_meta:__legacy__.build_wheel` failed (exit status: 1)

      [stdout]
      running bdist_wheel
      running build
      running build_py
      creating build/lib.linux-x86_64-cpython-39
      copying rundec.py -> build/lib.linux-x86_64-cpython-39
      running build_ext
      building '_rundec' extension
      creating build/temp.linux-x86_64-cpython-39/CRunDec3
      c++ -pthread -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -fPIC -DPy_LIMITED_API=0x030A0000
      -I/root/.cache/uv/builds-v0/.tmpwCZCqc/include -I/root/.local/share/uv/python/cpython-3.9.25-linux-x86_64-gnu/include/python3.9 -c CRunDec3/CRunDec.3.1.cpp -o
      build/temp.linux-x86_64-cpython-39/CRunDec3/CRunDec.3.1.o

      [stderr]
      error: command 'c++' failed: No such file or directory

      hint: This usually indicates a problem with the package or the build environment.

This would be protected against if requires-python metadata exists.

[DavidMStraub]

pip or uv with CPython older than Python 3.10 will still try to install v0.7+ and may fail if they do not have the required build tools on the install machine.

To me, that's the definition of "not supported".

You are right that metadata should be added to the setup.py, it is horribly outdated. And in fact we should migrate to pyproject.toml while we're at it. But I already spent to much time on this project today and won't have more time soon.

Would be happy about contributions to improve this.

[matthewfeickert]

To me, that's the definition of "not supported".

No, this is breaking every previous release of the package on any CPython that is older than Python 3.10. You do not want users on an older CPython version to try to install the library in a new virtual environment and get a broken install.

You are right that metadata should be added to the setup.py, it is horribly outdated. And in fact we should migrate to pyproject.toml while we're at it.

I would recommend starting at the Scientific Python Library Development Guide in the Packaging Compiled Projects section.

[DavidMStraub]

Agreed.

If you know what's the best way to fix it, a contribution would be highly welcome, rather than waiting for me to read guides.