CLinters 1.0.0

pre-commit hooks for C linters

pre-commit hooks

This is a pre-commit hooks repo that integrates C/C++ linters clang-format, clang-tidy, and oclint.

Example Usage

With int main() { int i; return 10; } in a file, all three linters should fail on commit:

The above uses this .pre-commit-config.yaml:

fail_fast: false
repos:
  - repo: https://github.com/pocc/pre-commit-hooks
    sha: master
    hooks:
      - id: clang-format
        args: [--style=Google]
      - id: clang-tidy
        args: [-checks=*, -warnings-as-errors=*]
      - id: oclint
        args: [-enable-clang-static-analyzer, -enable-global-analysis]

Note that for your config yaml, you can supply your own args or remove the args line entirely, depending on your use case.

Using the Hooks

Prerequisites

You will need to install these utilities in order to use them. Your package manager may already have them.

• brew install llvm oclint
• apt install clang-format clang-tidy oclint

Bash is required to use these hooks as all 3 invoking scripts are written in it.

Hook Info

	What it does	Fix Inplace
clang-format	Formats C/C++ code according to a style	-i
clang-tidy	clang-based C/C++ linter	-fix, --fix-errors [1]
oclint	static code analysis tool for C, C++ and Objective-C code	N/A

[1]: -fix will fail if there are compiler errors. -fix-errors will -fix and fix compiler errors if it can, like missing semicolons.

Enforcing linter version with --version

Some linters change behavior between versions. To enforce a linter version 8.0.0, for example, add --version=8.0.0 to args: for that linter. Note that this is a pre-commit hook arg and passing it to the linter will cause an error.

Compilation Database

clang-tidy and oclint both expect a compilation database. Both of the hooks for them will ignore the error for not having one.

You can generate with one cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON ... if you have a cmake-based project.

The -- option

Options after -- like -std=c++11 will be interpreted correctly for clang-tidy and oclint. Make sure they sequentially follow the -- argument in the hook's args list.

Testing

To run the tests and verify clang-format, clang-tidy, and oclint are working as expected on your system, use pytest --runslow. This will work on both bash and python branches.

Example testing with python branch

The default is to skip most (29/51) tests as to run them all takes ~60s. These pytest options are available to add test types:

• --runslow: oclint and clang-tidy -fix/--fix-errors tests take extra time
• --internal: Internal class tests to ensure internal/shell APIs match

Note: You can parallelize these tests with pytest-xdist. Adding -n 16 to the command divides runtime by ~6x in my testing.

To run all tests serially, run pytest -x -vvv --internal --runslow like so:

pre-commit-hooks$ pytest -x -vvv --internal --runslow
============================= test session starts ==============================
platform darwin -- Python 3.7.6, pytest-5.4.1, py-1.7.0, pluggy-0.13.1 -- /usr/local/opt/python/bin/python3.7
cachedir: .pytest_cache
rootdir: /Users/pre-commit-hooks/code/pre-commit-hooks, inifile: pytest.ini
collected 27 items

tests/test_hooks.py::TestHooks::test_run[run_cmd_class clang-format on /Users/pre-commit-hooks/code/pre-commit-hooks/tests/files/ok.c] PASSED [  3%]
tests/test_hooks.py::TestHooks::test_run[run_cmd_class clang-tidy on /Users/pre-commit-hooks/code/pre-commit-hooks/tests/files/ok.c] PASSED [  7%]
...

============================= 51 passed in 61.86s ==============================

Additional Resources

clang-format

• Official Docs
• clang-format Guide - a good overview and a great place to get started
• clang-format Configurator - Website to interactively design your config while
• clang-format Options Explorer - Website to interactively understand various options

clang-tidy

• Official Docs
• clang-tidy guide - Good place to start
• Example usage - Explanation of how to use clang-tidy by the creators of Kratos
• Add your own checks - Function names must be awesome!

oclint

• Official Docs
• Fastlane Integration

License

Apache 2.0