gh-110652: Fix pre-commit hooks on macOS

[erlend-aasland]

• Issue: The pre-commit hooks do not work on macOS #110652

[AlexWaygood]

This approach doesn't work on Windows, unfortunately, I don't think. I think I'd prefer using a python-language hook, as @hugovk suggested in #109891 (comment) (but see @AA-Turner's comments in #109891 (comment))

[hugovk]

Does this work on Windows?

cc @AA-Turner @AlexWaygood

[AlexWaygood]

Does this work on Windows?

no:

>pre-commit run --all-files
Run Ruff on Lib/test/....................................................Passed
Run Ruff on Argument Clinic..............................................Passed
check toml...............................................................Passed
check yaml...............................................................Passed
fix end of files.........................................................Passed
trim trailing whitespace.................................................Passed
Check Python file whitespace.............................................Failed
- hook id: python-file-whitespace
- exit code: 9009

Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.

Check C file whitespace..................................................Failed
- hook id: c-file-whitespace
- exit code: 9009

Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.

Sphinx lint..............................................................Passed
Check hooks apply to the repository......................................Passed
Check for useless excludes...............................................Passed

[AA-Turner]

It isn't well documented, but I had hoped language: script offered the salvation we desire. Sadly; no:

Check Python file whitespace.............................................Failed
- hook id: python-file-whitespace
- exit code: 1

Executable `python3` not found

Check C file whitespace..................................................Failed
- hook id: c-file-whitespace
- exit code: 1

Executable `python3` not found

This is, I think, as the shebang line says #! /usr/bin/env python3 -- if I change it to #! /usr/bin/env python, it passes for me. I'm not sure how to write such a line to choose between python3 or python, though.

A

[hugovk]

With:

        name: "Check Python file whitespace"
        entry: 'Tools/patchcheck/reindent.py --nobackup --newline LF'

And:

#! /usr/bin/env python

On macOS I get:

Executable `python` not found

[AlexWaygood]

@AA-Turner, in #109891 (comment) you commented that using a Python-language hook (rather than a system-language hook, as we have currently) might slow us down unnecessarily, as pre-commit would have to create a venv before the hook would run. But in my experience, the Python-language hooks in the pre-commit-hooks package are plenty fast enough. I think pre-commit might locally cache the venvs it creates, and reuse them in future invocations of the same hook?

[erlend-aasland]

@AlexWaygood, does 9501fab work on Windows?

[AlexWaygood]

@AlexWaygood, does 9501fab work on Windows?

Argh, that's still a no :((

>pre-commit run --all-files
[INFO] Initializing environment for local.
[INFO] Installing environment for local.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
Run Ruff on Lib/test/....................................................Passed
Run Ruff on Argument Clinic..............................................Passed
check toml...............................................................Passed
check yaml...............................................................Passed
fix end of files.........................................................Passed
trim trailing whitespace.................................................Passed
Check Python file whitespace.............................................Failed
- hook id: python-file-whitespace
- exit code: 9009

Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.

Check C file whitespace..................................................Failed
- hook id: c-file-whitespace
- exit code: 9009

Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.

Sphinx lint..............................................................Passed
Check hooks apply to the repository......................................Passed
Check for useless excludes...............................................Passed

[erlend-aasland]

Sounds like it's a pre-commit bug; their docs says it should work on Windows: https://pre-commit.com/#python

[AlexWaygood]

Sounds like it's a pre-commit bug; their docs says it should work on Windows: https://pre-commit.com/#python

The docs also say this, however, which isn't what we're doing:

The hook repository must be installable via pip install . (usually by either setup.py or pyproject.toml). The installed package will provide an executable that will match the entry – usually through console_scripts or scripts in setup.py.

I'm guessing this is the issue here -- the python-language hooks in the pre-commit-hooks repo are all installed hooks that have their own entry points: https://github.com/pre-commit/pre-commit-hooks/blob/27dcd3fd1dc01d3fdbeb188edb54dddf3d964236/setup.cfg#L31

[erlend-aasland]

Then let's make those scripts pip installable.

[erlend-aasland]

Closing; see issue.