clang-format.yml

name: clang-format

on:
  pull_request:
    paths:
      - '**.h'
      - '**.cpp'

concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  precheckin:
    runs-on: ubuntu-22.04
    steps:
      - name: Checkout PR branch
        uses: actions/checkout@v4
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          fetch-depth: 0

      - name: Setup Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install clang-format
        run: |
          curl https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
          os_codename="`cat /etc/os-release | grep UBUNTU_CODENAME | cut -d = -f 2`"
          echo "deb https://apt.llvm.org/${os_codename}/ llvm-toolchain-${os_codename}-18 main" | sudo tee -a /etc/apt/sources.list
          sudo apt update
          sudo apt install -y clang-format-18

      - name: Run git-clang-format
        run: |
          PR_BASE=$(git rev-list ${{ github.event.pull_request.head.sha }} ^${{ github.event.pull_request.base.sha }} | tail --lines 1 | xargs -I {} git rev-parse {}~1)
          echo "running git clang-format against $PR_BASE commit"
          git \
          -c color.ui=always \
          -c diff.wsErrorHighlight=all \
          -c color.diff.whitespace='red reverse' \
          clang-format-18 --diff --binary clang-format-18 --commit $PR_BASE -- include/ lib/ || \
          (echo "Please run the following git-clang-format locally to fix the formatting: \n
                git-clang-format HEAD~\n
                for multiple commits we should place the formatting changes in the related commit with:\n
                \t\tgit rebase -i -x \"git-clang-format-18 main && git commit -a --allow-empty --fixup=HEAD\" --strategy-option=theirs origin/main\n
                \t\t Then inspect the results with: git log --oneline\n
                \t\t Then squash without poluting the history with: git rebase --autosquash -i main\n" && exit 1)