name: Migration check

# A deploy migrates the database while the previous version may still be
# serving, and a rollback runs the previous version against the new schema.
# Both work only while a migration leaves the old code working, so this fails
# a pull request whose new migrations drop, rename, retype or tighten
# something (see .github/scripts/check-migrations.mjs). When such a change is
# safe anyway, add the allow-breaking-migration label and say why in the
# description; the label reruns this check.

on:
  pull_request:
    branches: [main]
    types: [opened, synchronize, reopened, labeled, unlabeled]
    paths: ["prisma/migrations/**"]

concurrency:
  group: migration-check-${{ github.ref }}
  cancel-in-progress: true

jobs:
  check:
    name: Migrations keep the running version working
    runs-on: ubuntu-latest
    timeout-minutes: 5
    steps:
      # The merge commit and its first parent, the base branch as it is now.
      - uses: actions/checkout@v4
        with:
          fetch-depth: 2

      - name: Check new and changed migrations
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'allow-breaking-migration') }}
        run: |
          mapfile -t files < <(git diff --name-only --diff-filter=AM HEAD^1 HEAD -- 'prisma/migrations/*/migration.sql')
          node .github/scripts/check-migrations.mjs "${files[@]}"

      - name: Allowed by label
        if: ${{ contains(github.event.pull_request.labels.*.name, 'allow-breaking-migration') }}
        run: echo "::notice title=Migration check skipped::The allow-breaking-migration label is on this pull request."