[BUG]: Python 3.12 will remove deprecated ImpImporter from pgkutil

[tacaswell]

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What version (or hash if on master) of pybind11 are you using?

main

Problem description

Processing /home/tcaswell/source/p/pybind/pybind11
  Preparing metadata (pyproject.toml): started
  Preparing metadata (pyproject.toml): finished with status 'error'

  error: subprocess-exited-with-error

  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [33 lines of output]
      Traceback (most recent call last):
        File "/home/tcaswell/.virtualenvs/bleeding/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/home/tcaswell/.virtualenvs/bleeding/lib/python3.12/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/tcaswell/.virtualenvs/bleeding/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 142, in prepare_metadata_for_build_wheel
          backend = _build_backend()
                    ^^^^^^^^^^^^^^^^
        File "/home/tcaswell/.virtualenvs/bleeding/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 77, in _build_backend
          obj = import_module(mod_path)
                ^^^^^^^^^^^^^^^^^^^^^^^
        File "/home/tcaswell/.pybuild/bleeding/lib/python3.12/importlib/__init__.py", line 124, in import_module
          return _bootstrap._gcd_import(name[level:], package, level)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "<frozen importlib._bootstrap>", line 1332, in _gcd_import
        File "<frozen importlib._bootstrap>", line 1305, in _find_and_load
        File "<frozen importlib._bootstrap>", line 1255, in _find_and_load_unlocked
        File "<frozen importlib._bootstrap>", line 400, in _call_with_frames_removed
        File "<frozen importlib._bootstrap>", line 1332, in _gcd_import
        File "<frozen importlib._bootstrap>", line 1305, in _find_and_load
        File "<frozen importlib._bootstrap>", line 1276, in _find_and_load_unlocked
        File "<frozen importlib._bootstrap>", line 841, in _load_unlocked
        File "<frozen importlib._bootstrap_external>", line 1027, in exec_module
        File "<frozen importlib._bootstrap>", line 400, in _call_with_frames_removed
        File "/home/tcaswell/.virtualenvs/bleeding/lib/python3.12/site-packages/setuptools/__init__.py", line 16, in <module>
          import setuptools.version
        File "/home/tcaswell/.virtualenvs/bleeding/lib/python3.12/site-packages/setuptools/version.py", line 1, in <module>
          import pkg_resources
        File "/home/tcaswell/.virtualenvs/bleeding/lib/python3.12/site-packages/pkg_resources/__init__.py", line 2191, in <module>
          register_finder(pkgutil.ImpImporter, find_on_path)
                          ^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'pkgutil' has no attribute 'ImpImporter'. Did you mean: 'zipimporter'?
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

This was caused by python/cpython#98573

Reproducible example code

Try to install pybind11 on development branch of CPython.

Is this a regression? Put the last known working version here if it is.

unlikely any version will work

[tacaswell]

Sigh, re-reading the error message a bit more carefully 15s after I posted I see that this is actually in setuptools.

Sorry for the noise.

[statetroopee]

Hello there,

I'm really new to python and I'm facing the same problem. How did you manage to solve this issue?

[tacaswell]

If I recall correctly, update setuptools. However if you are new to Python I am curious how you have ended up with a pre-release version of CPython (3.12 is not out yet).

You may be better served by using a released version (that will have built binary artifacts available via what ever package manager you prefer).

[RuthKassahun]

Downgrading to python==3.11 might help