clang-format-action

An action for clang-format checks. This action does NOT format your code for you - it only verifies that your repository's code follows your project's formatting conventions.

You can define your own formatting rules in a .clang-format file at your repository root, or you can provide a fallback style (see fallback-style). You can also provide a path to check. If you want to run checks against multiple paths in your repository, you can use this action in a matrix run.

Major versions supported

• 3: clang-format-3.9
• 4: clang-format-4.0
• 5: clang-format-5.0
• 6: clang-format-6.0
• 7: clang-format-7
• 8: clang-format-8
• 9: clang-format-9
• 10: clang-format-10
• 11: clang-format-11
• 12: clang-format-12
• 13: clang-format-13
• 14: clang-format-14
• 15: clang-format-15
• 16: clang-format-16
• 17: clang-format-17
• 18: clang-format-18

Action version upgrade guarantee

Important

This action complies with the Semantic Versioning spec for how it's called from GitHub Actions workflows. This means that for version format x.y.z, minor and patch version increments y++ and z++ will not break existing functionality for how this action is called in your GitHub Actions workflows. Major version increments (x++) will include breaking changes in how this action is called. If you notice version changes that violate this guarantee, open an issue and let's work together to fix it 😁.

Caution

I provide no guarantees for formatting breakages within clang-format versions. This action only supports major versions of clang-format and doesn't support granular specification of clang-format minor or patch versions. It's possible that a formatting check workflow using this action and a pinned version of clang-format could break in a subsequent run if the underlying clang-format Ubuntu package has introduced a breaking minor or patch version change. I'm not sure how often this happens - vote in this poll and optionally leave a comment so I can understand this problem more.

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Inputs

• clang-format-version [optional]: The major version of clang-format that you want to run on your codebase.
  • Default: 13
  • Available versions: see Versions supported
• check-path [optional]: The path to the directory in the repo that should be checked for C/C++/Protobuf formatting.
  • Default: .
  • For cleaner output (i.e. with no double-slashed paths), the final directory in this path should have no trailing slash, e.g. src and not src/.
• fallback-style [optional]: The fallback style for clang-format if no .clang-format file exists in your repository.
  • Default: llvm
  • Available values: LLVM, Google, Chromium, Mozilla, WebKit and others listed in the clang-format docs for BasedOnStyle.
• exclude-regex [optional]: A regex to exclude files or directories that should not be checked.
  • Default: ^$
  • Pattern matching is done with a POSIX grep -E extended regex, not a glob expression. You can exclude multiple patterns like this: (hello|world). Build and verify your regex at regex101.com (example).
• include-regex [optional]: A regex to include files or directories that should be checked.
  • Default: see INCLUDE_REGEX
  • Pattern matching is done with a POSIX grep -E extended regex, not a glob expression. You can exclude multiple patterns like this: (hello|world). Build and verify your regex at regex101.com (example).

This action checks all C/C++/Protobuf (including Arduino .ino and .pde) files in the provided directory in the GitHub workspace are formatted correctly using clang-format. If no directory is provided or the provided path is not a directory in the GitHub workspace, all C/C++/Protobuf files are checked.

The following file extensions are checked by default:

• Header files:
  • .h
  • .H
  • .hpp
  • .hh
  • .h++
  • .hxx
• Source files:
  • .c
  • .C
  • .cpp
  • .cc
  • .c++
  • .cxx
  • .ino
  • .pde
  • .cu
• Protobuf files:
  • .proto

Returns:

• SUCCESS: zero exit-code if C/C++/Protobuf files in check-path are formatted correctly
• FAILURE: nonzero exit-code if C/C++/Protobuf files in check-path are not formatted correctly

Usage

Warning

This action is not supported on windows GitHub Actions runners!

Single Path

To use this action, create a .github/workflows/clang-format-check.yml in your repository containing:

name: clang-format Check
on: [push, pull_request]
jobs:
  formatting-check:
    name: Formatting Check
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4
    - name: Run clang-format style check for C/C++/Protobuf programs.
      uses: jidicula/clang-format-action@v4.13.0
      with:
        clang-format-version: '13'
        check-path: 'src'
        fallback-style: 'Mozilla' # optional

Multiple Paths

To use this action on multiple paths in parallel, create a .github/workflows/clang-format-check.yml in your repository containing:

name: clang-format Check
on: [push, pull_request]
jobs:
  formatting-check:
    name: Formatting Check
    runs-on: ubuntu-latest
    strategy:
      matrix:
        path:
          - 'src'
          - 'examples'
    steps:
    - uses: actions/checkout@v4
    - name: Run clang-format style check for C/C++/Protobuf programs.
      uses: jidicula/clang-format-action@v4.13.0
      with:
        clang-format-version: '13'
        check-path: ${{ matrix.path }}
        fallback-style: 'Mozilla' # optional

Multiple Paths with Exclusion Regexes

To use this action on multiple paths in parallel with exclusions, create a .github/workflows/clang-format-check.yml in your repository containing:

name: clang-format Check
on: [push, pull_request]
jobs:
  formatting-check:
    name: Formatting Check
    runs-on: ubuntu-latest
    strategy:
      matrix:
        path:
          - check: 'src'
            exclude: '(hello|world)' # Exclude file paths containing "hello" or "world"
          - check: 'examples'
            exclude: ''              # Nothing to exclude
    steps:
    - uses: actions/checkout@v4
    - name: Run clang-format style check for C/C++/Protobuf programs.
      uses: jidicula/clang-format-action@v4.13.0
      with:
        clang-format-version: '13'
        check-path: ${{ matrix.path['check'] }}
        exclude-regex: ${{ matrix.path['exclude'] }}
        fallback-style: 'Mozilla' # optional

Who uses this?

These public repos use this Action.