format.yml

name: pre-commit (PR only on changed files)

on:
  pull_request:
    types: [opened, synchronize, reopened]

permissions:
  contents: read

jobs:
  detect_changes:
    runs-on: ubuntu-latest
    outputs:
      changed: ${{ steps.changed_files.outputs.changed }}

    steps:
      - name: Checkout PR
        uses: actions/checkout@v6
        with:
          fetch-depth: 0
          persist-credentials: false

      - name: Detect changed files
        id: changed_files
        run: |
          # git fetch origin ${{ github.base_ref }}
          # CHANGED_FILES=$(git diff --name-only origin/${{ github.base_ref }}...HEAD)
          BASE_SHA="${{ github.event.pull_request.base.sha }}"
          HEAD_SHA="${{ github.event.pull_request.head.sha }}"

          echo "Base SHA: $BASE_SHA"
          echo "Head SHA: $HEAD_SHA"

          CHANGED_FILES=$(git diff --name-only "$BASE_SHA" "$HEAD_SHA")

          {
            echo "changed<<EOF"
            echo "$CHANGED_FILES"
            echo "EOF"
          } >> "$GITHUB_OUTPUT"

      - name: Show changed files
        run: |
          echo "Changed files:"
          echo "${{ steps.changed_files.outputs.changed }}"

  precommit:
    needs: detect_changes
    runs-on: ubuntu-latest
    if: ${{ needs.detect_changes.outputs.changed != '' }}

    steps:
      - name: Checkout PR head commit
        uses: actions/checkout@v6
        with:
          fetch-depth: 0
          ref: ${{ github.event.pull_request.head.sha }}
          persist-credentials: false

      - name: Set up Python
        uses: actions/setup-python@v6
        with:
          python-version: "3.12"

      - name: Install pre-commit
        run: pip install pre-commit

      - name: Run pre-commit (CI check-only stage) on changed files
        env:
          CHANGED_FILES: ${{ needs.detect_changes.outputs.changed }}
        run: |
          mapfile -t files <<< "$CHANGED_FILES"
          pre-commit run --hook-stage manual --files "${files[@]}" --show-diff-on-failure