#20354 Most built-in tool lockfiles do not work with Python 3.12 Issue created by huonw Describe the bug The built-in lockfiles for tools like: pytest, mypy, ..., use pip 23.0.1, which doesn't work with Python 3.12:

13:28:11.08 [INFO] Completed: Building pytest.pex from <resource://pants.backend.python.subsystems/pytest.lock>
13:28:11.09 [ERROR] 1 Exception encountered:

Engine traceback:
  in `test` goal

ProcessExecutionFailure: Process 'Building pytest.pex from <resource://pants.backend.python.subsystems/pytest.lock>' failed with exit code 1.
stdout:

stderr:
The Pip requested was pip==23.0.1 but it does not work with the interpreter selected which is CPython 3.12.0 at /Users/huon/.pyenv/versions/3.12.0/bin/python3.12. Pip 23.0.1 requires Python <3.12,>=3.7.

Reproducer:

cd $(mktemp -d)

cat > pants.toml <<EOF
[GLOBAL]
pants_version = "2.19.0rc2"

backend_packages = [
  "pants.backend.python",
]

[python]
interpreter_constraints = ["==3.12.*"]
EOF

echo 'python_tests(name="t")' > BUILD
echo 'def test_foo(): pass' > test_example.py

# BUG: fails by default with Python 3.12
pants test ::
#> The Pip requested was pip==23.0.1 but it does not work with the interpreter selected which is CPython 3.12.0 at /Users/huon/.pyenv/versions/3.12.0/bin/python3.12. Pip 23.0.1 requires Python <3.12,>=3.7.

# OKAY: works fine
pants test --python-interpreter-constraints='["==3.11.*"]' ::

Workaround: use custom lockfiles, with `python_requirement`s/`install_from_resolve`. Pants version 2.19.0rc2 (NB. 2.18.1 uses a version of pex that doesn't support Python 3.12 by default, but would likely be still affected by this if one specifies a newer pex in

[pex-cli]

.) OS macOS Additional info Discussed in #20310 (review) Details of pip version support in https://github.com/pantsbuild/pex/blob/4eb5c9aa25c6a695bf55263ab239189b720cebaf/pex/pip/version.py#L128-L233 See https://github.com/search?q=repo%3Apantsbuild%2Fpants%20pip_version%2023.0.1&type=code for 27 current lock files using pip version 23.0.1. pantsbuild/pants

@broad-processor-92400 this one has been approved 😄 thank you for authoring it! it solves a lot of issues we're having with python 3.12