format-check.yml

name: Format Check

on:
  pull_request:
    branches: [main]

jobs:
  changes:
    name: Detect source changes
    runs-on: ubuntu-latest
    outputs:
      relevant: ${{ steps.filter.outputs.relevant }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - name: Detect relevant file changes
        id: filter
        shell: bash
        run: |
          if [ "${{ github.event_name }}" != "pull_request" ]; then
            echo "relevant=true" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          if git diff --name-only "${{ github.event.pull_request.base.sha }}" "${{ github.event.pull_request.head.sha }}" | grep -q '^src/'; then
            echo "relevant=true" >> "$GITHUB_OUTPUT"
          else
            echo "relevant=false" >> "$GITHUB_OUTPUT"
          fi

  clang-format:
    name: clang-format
    needs: changes
    if: needs.changes.outputs.relevant == 'true'
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          fetch-depth: 1

      - name: Install clang-format
        run: sudo apt-get update && sudo apt-get install -y clang-format

      - name: Check formatting
        run: |
          FAILED=0
          FILES=$(find src/ -type f \( -name "*.cpp" -o -name "*.hpp" -o -name "*.h" \))

          for file in $FILES; do
            # Generate the diff between current and formatted versions
            DIFF=$(clang-format "$file" | diff -u "$file" - || true)
            if [ -n "$DIFF" ]; then
              echo "::error file=$file::File is not formatted according to .clang-format"
              echo "$DIFF"
              echo ""
              FAILED=1
            fi
          done

          if [ "$FAILED" -eq 1 ]; then
            echo ""
            echo "Some files are not properly formatted."
            echo ""
            echo "Fix locally with:"
            echo '  find src/ -type f \( -name "*.cpp" -o -name "*.hpp" -o -name "*.h" \) | xargs clang-format -i'
            exit 1
          fi

          echo "All files are properly formatted."