Replace cpplint with clang-format

[WillAyd]

cpplint isn't seemingly well maintained and focuses on C++, which we aren't using. I think clang-format is a much better tool for our formatting

[WillAyd]

Since we are adding a hook to pre-commit I'm guessing pre-commit.ci will have to be updated somehow to account for it. Does @MarcoGorelli or @lithomas1 know how that works?

[lithomas1]

Since we are adding a hook to pre-commit I'm guessing pre-commit.ci will have to be updated somehow to account for it. Does @MarcoGorelli or @lithomas1 know how that works?

I think Marco's out on vacation right now, so I'll do my best to help.

Can we try not using pocc's wrapper around clang-format? I think that one doesn't install clang-format for you, so it won't work on pre-commit CI.

You can try adding something manual like

pandas/.pre-commit-config.yaml

Lines 131 to 388 in cc58350

	hooks:
	- id: pyright
	# note: assumes python env is setup and activated
	name: pyright
	entry: pyright
	language: node
	pass_filenames: false
	types: [python]
	stages: [manual]
	additional_dependencies: &pyright_dependencies
	- pyright@1.1.318
	- id: pyright
	# note: assumes python env is setup and activated
	name: pyright reportGeneralTypeIssues
	entry: pyright --skipunannotated -p pyright_reportGeneralTypeIssues.json --level warning
	language: node
	pass_filenames: false
	types: [python]
	stages: [manual]
	additional_dependencies: *pyright_dependencies
	- id: mypy
	# note: assumes python env is setup and activated
	name: mypy
	entry: mypy
	language: system
	pass_filenames: false
	types: [python]
	stages: [manual]
	- id: mypy
	# note: assumes python env is setup and activated
	# note: requires pandas dev to be installed
	name: mypy (stubtest)
	entry: python
	language: system
	pass_filenames: false
	types: [pyi]
	args: [scripts/run_stubtest.py]
	stages: [manual]
	- id: inconsistent-namespace-usage
	name: 'Check for inconsistent use of pandas namespace'
	entry: python scripts/check_for_inconsistent_pandas_namespace.py
	exclude: ^pandas/core/interchange/
	language: python
	types: [python]
	- id: unwanted-patterns
	name: Unwanted patterns
	language: pygrep
	entry: |
	(?x)
	# outdated annotation syntax
	\#\ type:\ (?!ignore)
	# foo._class__ instead of type(foo)
	|\.__class__
	# Numpy
	|from\ numpy\ import\ random
	|from\ numpy\.random\ import
	# Incorrect code-block / IPython directives
	|\.\.\ code-block\ ::
	|\.\.\ ipython\ ::
	# directive should not have a space before ::
	|\.\.\ \w+\ ::
	# Check for deprecated messages without sphinx directive
	|(DEPRECATED|DEPRECATE|Deprecated)(:|,|\.)
	# {foo!r} instead of {repr(foo)}
	|!r}
	# builtin filter function
	|(?<!def)[\(\s]filter\(
	types_or: [python, cython, rst]
	exclude: ^doc/source/development/code_style\.rst # contains examples of patterns to avoid
	- id: incorrect-backticks
	name: Check for backticks incorrectly rendering because of missing spaces
	language: pygrep
	entry: '[a-zA-Z0-9]\`\`?[a-zA-Z0-9]'
	types: [rst]
	files: ^doc/source/
	- id: seed-check-asv
	name: Check for unnecessary random seeds in asv benchmarks
	language: pygrep
	entry: 'np\.random\.seed'
	files: ^asv_bench/benchmarks
	exclude: ^asv_bench/benchmarks/pandas_vb_common\.py
	- id: unwanted-patterns-in-tests
	name: Unwanted patterns in tests
	language: pygrep
	entry: |
	(?x)
	# pytest.xfail instead of pytest.mark.xfail
	pytest\.xfail
	# imports from pandas._testing instead of `import pandas._testing as tm`
	|from\ pandas\._testing\ import
	|from\ pandas\ import\ _testing\ as\ tm
	# No direct imports from conftest
	|conftest\ import
	|import\ conftest
	# pandas.testing instead of tm
	|pd\.testing\.
	# pd.api.types instead of from pandas.api.types import ...
	|(pd|pandas)\.api\.types\.
	# np.testing, np.array_equal
	|(numpy|np)(\.testing|\.array_equal)
	# unittest.mock (use pytest builtin monkeypatch fixture instead)
	|(unittest(\.| import )mock|mock\.Mock\(\)|mock\.patch)
	# pytest raises without context
	|\s\ pytest.raises
	# pytest.warns (use tm.assert_produces_warning instead)
	|pytest\.warns
	# os.remove
	|os\.remove
	# Unseeded numpy default_rng
	|default_rng\(\)
	files: ^pandas/tests/
	types_or: [python, cython, rst]
	- id: unwanted-patterns-in-cython
	name: Unwanted patterns in Cython code
	language: pygrep
	entry: |
	(?x)
	# `<type>obj` as opposed to `<type> obj`
	[a-zA-Z0-9*]>[ ]
	types: [cython]
	- id: pip-to-conda
	name: Generate pip dependency from conda
	language: python
	entry: python scripts/generate_pip_deps_from_conda.py
	files: ^(environment.yml|requirements-dev.txt)$
	pass_filenames: false
	additional_dependencies: [tomli, pyyaml]
	- id: title-capitalization
	name: Validate correct capitalization among titles in documentation
	entry: python scripts/validate_rst_title_capitalization.py
	language: python
	types: [rst]
	files: ^doc/source/(development|reference)/
	- id: unwanted-patterns-bare-pytest-raises
	name: Check for use of bare pytest raises
	language: python
	entry: python scripts/validate_unwanted_patterns.py --validation-type="bare_pytest_raises"
	types: [python]
	files: ^pandas/tests/
	exclude: ^pandas/tests/extension/
	- id: unwanted-patterns-private-function-across-module
	name: Check for use of private functions across modules
	language: python
	entry: python scripts/validate_unwanted_patterns.py --validation-type="private_function_across_module"
	types: [python]
	exclude: ^(asv_bench|pandas/tests|doc)/
	- id: unwanted-patterns-private-import-across-module
	name: Check for import of private attributes across modules
	language: python
	entry: python scripts/validate_unwanted_patterns.py --validation-type="private_import_across_module"
	types: [python]
	exclude: |
	(?x)
	^(asv_bench|pandas/tests|doc)/
	|scripts/validate_min_versions_in_sync\.py$
	- id: unwanted-patterns-strings-with-misplaced-whitespace
	name: Check for strings with misplaced spaces
	language: python
	entry: python scripts/validate_unwanted_patterns.py --validation-type="strings_with_wrong_placed_whitespace"
	types_or: [python, cython]
	- id: unwanted-patterns-nodefault-used-not-only-for-typing
	name: Check that `pandas._libs.lib.NoDefault` is used only for typing
	language: python
	entry: python scripts/validate_unwanted_patterns.py --validation-type="nodefault_used_not_only_for_typing"
	types: [python]
	- id: use-pd_array-in-core
	name: Import pandas.array as pd_array in core
	language: python
	entry: python scripts/use_pd_array_in_core.py
	files: ^pandas/core/
	exclude: ^pandas/core/api\.py$
	types: [python]
	- id: use-io-common-urlopen
	name: Use pandas.io.common.urlopen instead of urllib.request.urlopen
	language: python
	entry: python scripts/use_io_common_urlopen.py
	files: ^pandas/
	exclude: ^pandas/tests/
	types: [python]
	- id: no-bool-in-core-generic
	name: Use bool_t instead of bool in pandas/core/generic.py
	entry: python scripts/no_bool_in_generic.py
	language: python
	files: ^pandas/core/generic\.py$
	- id: no-return-exception
	name: Use raise instead of return for exceptions
	language: pygrep
	entry: 'return [A-Za-z]+(Error|Exit|Interrupt|Exception|Iteration)'
	files: ^pandas/
	types: [python]
	exclude: ^pandas/tests/
	- id: pandas-errors-documented
	name: Ensure pandas errors are documented in doc/source/reference/testing.rst
	entry: python scripts/pandas_errors_documented.py
	language: python
	files: ^pandas/errors/__init__.py$
	- id: pg8000-not-installed-CI
	name: Check for pg8000 not installed on CI for test_pg8000_sqlalchemy_passthrough_error
	language: pygrep
	entry: 'pg8000'
	files: ^ci/deps
	types: [yaml]
	- id: validate-min-versions-in-sync
	name: Check minimum version of dependencies are aligned
	entry: python -m scripts.validate_min_versions_in_sync
	language: python
	files: ^(ci/deps/actions-.*-minimum_versions\.yaml|pandas/compat/_optional\.py)$
	additional_dependencies: [tomli, pyyaml]
	pass_filenames: false
	- id: validate-errors-locations
	name: Validate errors locations
	description: Validate errors are in appropriate locations.
	entry: python scripts/validate_exception_location.py
	language: python
	files: ^pandas/
	exclude: ^(pandas/_libs/|pandas/tests/|pandas/errors/__init__.py$|pandas/_version.py)
	types: [python]
	- id: future-annotations
	name: import annotations from __future__
	entry: 'from __future__ import annotations'
	language: pygrep
	args: [--negate]
	files: ^pandas/
	types: [python]
	exclude: |
	(?x)
	/(__init__\.py)|(api\.py)|(_version\.py)|(testing\.py)|(conftest\.py)$
	|/tests/
	|/_testing/
	- id: check-test-naming
	name: check that test names start with 'test'
	entry: python -m scripts.check_test_naming
	types: [python]
	files: ^pandas/tests
	language: python
	- id: sort-whatsnew-items
	name: sort whatsnew entries alphabetically
	entry: python -m scripts.sort_whatsnew_note
	types: [rst]
	language: python
	files: ^doc/source/whatsnew/v
	exclude: ^doc/source/whatsnew/v(0|1|2\.0\.0)

(see the pyright one.
We can try adding a new entry something like

id: clang-format
name: clang-format
entry: << clang-format command goes here >>
language: conda
additional_dependencies:
- clang-format

(I'm just typing this off of my head. Idea is to get pre-commit to pull clang-format off of conda. Don't expect it to work out of the box, though)

[WillAyd]

Ah OK thanks. I'll give that a shot - didn't realize pocc was missing something compared to the other repo to auto install

[WillAyd]

Any concerns on this one?

[lithomas1]

Thanks Will,

This LGTM.

@MarcoGorelli any thoughts on this one?

[MarcoGorelli]

sorry for the delay, looks really good, nice one!

[mroeschke]

Could you use https://github.com/pre-commit/mirrors-clang-format instead?

[mroeschke]

Thanks @WillAyd