name: Lockfile

on:
  pull_request:
concurrency:
  group: '${{ github.workflow }}-${{ github.head_ref || github.ref }}'
  cancel-in-progress: true

jobs:
  verify-yarn-lock:
    name: No manual yarn.lock edits
    runs-on: ubuntu-latest
    steps:
      - name: Check out PR HEAD
        uses: actions/checkout@v3
        with:
          fetch-depth: 0

      - name: Fetch base branch
        run: git fetch origin ${{ github.base_ref }} --depth=1

      - name: Install node
        uses: actions/setup-node@v4
        with:
          node-version-file: .nvmrc

      - name: Reset yarn.lock to base
        run: git show "origin/${{ github.base_ref }}:yarn.lock" > yarn.lock

      - name: Yarn install
        uses: Wandalen/wretry.action@master
        with:
          # Fine to skip scripts since we don't run any code
          command: yarn install --ignore-scripts
          attempt_limit: 3
          attempt_delay: 2000

      - name: Verify yarn.lock
        run: |
          git diff --quiet --exit-code || {
            echo '::error::`yarn.lock` does not match what Yarn would generate given the base `yarn.lock` and the head `package.json`.'
            echo '::error:: - If this is intentional, you can ignore this check.'
            echo '::error:: - If this is unintentional, apply the following diff:'
            git --no-pager diff
            exit 1
          }