name: "Check code formatting"
on: pull_request_target
permissions:
  pull-requests: write

jobs:
  code_formatter:
    runs-on: ubuntu-latest
    if: github.repository == 'llvm/llvm-project'
    steps:
      - name: Fetch LLVM sources
        uses: actions/checkout@v4
        with:
          ref: ${{ github.event.pull_request.head.sha }}

      - name: Checkout through merge base
        uses: rmacklin/fetch-through-merge-base@v0
        with:
          base_ref: ${{ github.event.pull_request.base.ref }}
          head_ref: ${{ github.event.pull_request.head.sha }}
          deepen_length: 500

      - name: Get changed files
        id: changed-files
        uses: tj-actions/changed-files@v39
        with:
          separator: ","
          skip_initial_fetch: true

      # We need to make sure that we aren't executing/using any code from the
      # PR for security reasons as we're using pull_request_target. Checkout
      # the target branch with the necessary files.
      - name: Fetch code formatting utils
        uses: actions/checkout@v4
        with:
          sparse-checkout: |
            llvm/utils/git/requirements_formatting.txt
            llvm/utils/git/code-format-helper.py
          sparse-checkout-cone-mode: false
          path: code-format-tools

      - name: "Listed files"
        env:
          CHANGED_FILES: ${{ steps.changed-files.outputs.all_changed_files }}
        run: |
          echo "Formatting files:"
          echo "$CHANGED_FILES"

      - name: Install clang-format
        uses: aminya/setup-cpp@v1
        with:
          clangformat: 17.0.1

      - name: Setup Python env
        uses: actions/setup-python@v4
        with:
          python-version: '3.11'
          cache: 'pip'
          cache-dependency-path: 'code-format-tools/llvm/utils/git/requirements_formatting.txt'

      - name: Install python dependencies
        run: pip install -r code-format-tools/llvm/utils/git/requirements_formatting.txt

      - name: Run code formatter
        env:
          GITHUB_PR_NUMBER: ${{ github.event.pull_request.number }}
          START_REV: ${{ github.event.pull_request.base.sha }}
          END_REV: ${{ github.event.pull_request.head.sha }}
          CHANGED_FILES: ${{ steps.changed-files.outputs.all_changed_files }}
        # TODO(boomanaiden154): Once clang v18 is released, we should be able
        # to take advantage of the new --diff_from_common_commit option
        # explicitly in code-format-helper.py and not have to diff starting at
        # the merge base.
        run: |
          python ./code-format-tools/llvm/utils/git/code-format-helper.py \
            --token ${{ secrets.GITHUB_TOKEN }} \
            --issue-number $GITHUB_PR_NUMBER \
            --start-rev $(git merge-base $START_REV $END_REV) \
            --end-rev $END_REV \
            --changed-files "$CHANGED_FILES"