Pyston compatibility for the test suite - #7901

This is exciting, I didn't even know Numba worked on Pyston! Slightly tangential, but how easy is it to add Pyston to the Azure CI tests?

This is exciting, I didn't even know Numba worked on Pyston! Slightly tangential, but how easy is it to add Pyston to the Azure CI tests?

Indeed, great to see Numba works with Pyston.

RE Azure. I think it'd require a llvmlite development conda package that works under Pyston adding to the numba channel somewhere. Other than that I think it's just selectively adding in some conda channels and probably a e.g. $PYTHON_IMPL identifier to the build scripts/Azure config.

Notes:

• Initially CUDA tests were failing on Pyston, segfault very early on in library loading, I then installed SciPy from conda-forge and it seemed to "fix it" and all the CUDA tests passed, even though the SciPy build itself was broken, no idea why as yet (imagine it's to do with changing some underlying libraries to get SciPy to install)!
• Seems like there's no suitable SciPy build for Pyston so could not run the numba.tests.test_linalg tests which use SciPy's BLAS/LAPACK bindings.

One note (mentioned OOB, but putting here for posterity) is that current Pyston conda packages are built in the conda-forge style, using the python_abi method for managing alternative interpreters. Anaconda's packages don't yet do this, so testing with Pyston should be done in an environment built this way to avoid contamination by packages with an incompatible ABI:

conda create -n pyston_env  # create an empty environment
conda activate pyston_env
echo 'channels: [pyston,conda-forge]' | conda config --env --stdin
conda install pyston # add whatever other packages you want

(reference: https://github.com/pyston/pyston/wiki/Using-conda)