format-code.yml

name: "Format C++ code"

on:
  issue_comment:
    types: [created]

jobs:
  format:
    name: "Format C++ code"
    runs-on: ubuntu-latest
    if: github.event.issue.pull_request != '' && (contains(github.event.comment.body, '/format') || contains(github.event.comment.body, '/clang-format'))
    steps:
      - name: "Checkout code"
        run: |
          PR_DATA="/tmp/pr.json"

          jq -r ".issue.pull_request.url" "$GITHUB_EVENT_PATH" | \
            xargs curl --header 'authorization: Bearer ${{ secrets.GITHUB_TOKEN }}' -o "$PR_DATA" --url

          HEAD_REF=$(jq -r ".head.ref" "$PR_DATA")
          HEAD_REPO=$(jq -r '.head.repo.clone_url | sub("https://"; "https://x-access-token:${{ secrets.GITHUB_TOKEN }}@")' "$PR_DATA")

          git clone $HEAD_REPO .
          git checkout -b "$HEAD_REF" "origin/$HEAD_REF"

      - name: "Format C++ code"
        run: |
          # Use clang-format to format the added or modified C++ files in the PR (if any)
          jq -r '.issue.pull_request.url | . += "/files"' "$GITHUB_EVENT_PATH" | \
            xargs curl --header 'authorization: Bearer ${{ secrets.GITHUB_TOKEN }}' --url | \
            jq -r -c '.[] | select(.status == "added" or .status == "modified") | select(.filename | match("(?<!catch)\\.(cpp|hpp|h)$")) | .filename' | \
            xargs clang-format -i

      - name: "Commit formatted C++ code"
        run: |
          # Check if there is nothing to commit (i.e. no formatting changes made)
          if [ -z "$(git status --porcelain)" ]; then
            echo "Code is already formatted correctly"
            exit 0
          fi

          # Setup the git user (required to commit anything)
          git config --global user.email "github-actions[bot]@users.noreply.github.com"
          git config --global user.name "github-actions[bot]"

          # Commit the changes made by clang-format
          git add .
          git commit -m "[CI] Format C++ code"
          git push