WIP: move from pkg_resources -> importlib

[dlakaplan]

pkg_resources is deprecated, and removed from 3.12

[abhisrkckl]

This is the error in oldestdeps. This error happens in Python 3.8 and earlier.

AttributeError: module 'importlib.resources' has no attribute 'files'

We have the motivation to drop 3.8 support now I guess @scottransom

[dlakaplan]

So consistently oldestdeps is failing in various ways. Still trying to understand how/why. Errors look like:

oldestdeps: install_deps> python -I -m pip install astropy==4.0 coverage 'hypothesis<=6.72.0' matplotlib==3.2.0 numdifftools==0.9.39 numpy==1.18.5 pytest scipy==1.4.1
  error: subprocess-exited-with-error
  
  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [24 lines of output]
      Running from numpy source directory.
      <string>:461: UserWarning: Unrecognized setuptools command, proceeding with generating Cython sources and expanding templates
      Traceback (most recent call last):
        File "/home/runner/work/PINT/PINT/.tox/oldestdeps/lib/python3.9/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/home/runner/work/PINT/PINT/.tox/oldestdeps/lib/python3.9/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
        File "/home/runner/work/PINT/PINT/.tox/oldestdeps/lib/python3.9/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 149, in prepare_metadata_for_build_wheel
          return hook(metadata_directory, config_settings)
        File "/tmp/pip-build-env-x77knkfs/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 373, in prepare_metadata_for_build_wheel
          self.run_setup()
        File "/tmp/pip-build-env-x77knkfs/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 516, in run_setup
          super().run_setup(setup_script=setup_script)
        File "/tmp/pip-build-env-x77knkfs/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 318, in run_setup
          exec(code, locals())
        File "<string>", line 488, in <module>
        File "<string>", line 465, in setup_package
        File "/tmp/pip-install-y2fx9cjh/numpy_3ab6bbeb0022406ba820805ecb601263/numpy/distutils/core.py", line 26, in <module>
          from numpy.distutils.command import config, config_compiler, \
        File "/tmp/pip-install-y2fx9cjh/numpy_3ab6bbeb0022406ba820805ecb601263/numpy/distutils/command/config.py", line 20, in <module>
          from numpy.distutils.mingw32ccompiler import generate_manifest
        File "/tmp/pip-install-y2fx9cjh/numpy_3ab6bbeb0022406ba820805ecb601263/numpy/distutils/mingw32ccompiler.py", line 34, in <module>
          from distutils.msvccompiler import get_build_version as get_build_msvc_version
      ModuleNotFoundError: No module named 'distutils.msvccompiler'
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

[dlakaplan]

What I am trying is to locally find a combination of numpy/scipy/matplotlib/astropy that will install with python 3.9. The default for oldestdeps is:

    numpy==1.18.5
    astropy==4.0
    matplotlib==3.2.0
    scipy==1.4.1

but I've had trouble with all of those. On the other hand, I have a local environment working with:
numpy==1.23.5 scipy==1.13.0 matplotlib==3.4.3 astropy==6.0
so I am trying to work back from there and see which of those can be taken earlier. Don't know how to do that systematically.

[dlakaplan]

Looks like this is a possible combination for oldestdeps:

    numpy==1.23.0
    astropy==5.0.5
    matplotlib==3.4.3
    scipy==1.9.0