Pull Request の差分に対して swift-format でフォーマットして commit & push する GitHub Actions の設定

swift-format.yml

# Pull Request の差分に対して swift-format でフォーマットして commit & push
name: swift-format

on:
  pull_request:
    branches:
      - main
    paths:
      - "**/*.swift"

defaults:
  run:
    shell: bash -euo pipefail {0}

concurrency: # 自動キャンセル
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  format:
    runs-on: macos-14
    steps:
      - name: Install swift-format
        run: |
          brew install swift-format
      - name: PR commits + 1
        id: pre_fetch_depth
        run: echo "depth=$(( ${{ github.event.pull_request.commits }} + 1 ))" >> "${GITHUB_OUTPUT}"
      - name: Checkout PR branch and all PR commits
        uses: actions/checkout@v4
        with:
          ref: ${{ github.event.pull_request.head.ref }}
          fetch-depth: ${{ steps.pre_fetch_depth.outputs.depth }} # (PR の commits + 1) 個 checkout する
      - name: Find swift files to format
        run: |
          SWIFT_FILES=()
          while IFS="" read -r file; do SWIFT_FILES+=("${file}"); done < <(git diff --name-only --diff-filter=AMRC ${{ github.event.pull_request.base.sha }} -- "*.swift")
          if [ "${#SWIFT_FILES[@]}" -eq 0 ]; then
            echo "No changes to format"
          else
            swift-format format --in-place --configuration .swift-format.json --parallel "${SWIFT_FILES[@]}" || true
          fi
      - name: Commit and Push changes
        env:
          HEAD_REF: ${{ github.head_ref }}
        run: |
          git config --local user.name "github-actions[bot]"
          git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git add .
          if git commit -m "[GitHub Actions] swift-format"; then
            echo "Changes committed, pushing to repository..."
            git push origin HEAD:"${HEAD_REF}"
          else
            echo "No changes to commit"
          fi