format.yml

name: Clang format

on: [pull_request]

jobs:
  clang-format:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
      with:
        ref: ${{ github.event.pull_request.head.sha }}

    - name: Install prerequisites
      run: |
        sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-11 100
        sudo update-alternatives --install /usr/bin/git-clang-format git-clang-format /usr/bin/git-clang-format-11 100

    - name: Run clang-format on changed files
      run: |
        set -x
        git fetch origin ${{ github.event.pull_request.base.ref }}
        base_commit=$(git rev-parse ${{ github.event.pull_request.base.sha }})
        result_output=$(git diff --diff-filter d --name-only "$base_commit" |
                          xargs -d '\n' git-clang-format --commit "$base_commit" --diff --style file)
        if [ "$result_output" = 'no modified files to format' ] ||
           [ "$result_output" = 'clang-format did not modify any files' ]
        then
          exit 0
        else
          git-clang-format --commit "$base_commit" --diff --style file
          echo "$result_output"
          exit 1
        fi