enforce-groovy-migration.yaml

name: Enforce Groovy Migration
on:
  pull_request:
    types: [opened, edited, ready_for_review, labeled, unlabeled, synchronize]
    branches:
      - master
      - "release/v*"

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

jobs:
  enforce_groovy_migration:
    name: Enforce Groovy migration
    permissions:
      id-token: write # Required for OIDC token federation
      issues: write # Required to create a comment on the pull request
      pull-requests: write # Required to create a comment on the pull request
    runs-on: ubuntu-latest
    steps:
      - name: Get GitHub Token via dd-octo-sts
        id: generate-token
        uses: DataDog/dd-octo-sts-action@96a25462dbcb10ebf0bfd6e2ccc917d2ab235b9a # v1.0.4
        with:
          scope: DataDog/dd-trace-java
          policy: self.enforce-groovy-migration
      - name: Check for new Groovy files
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # 9.0.0
        with:
          github-token: ${{ steps.generate-token.outputs.token }}
          script: |
            const managedMarker = '<!-- dd-trace-java-groovy-enforcement -->'

            const deleteManagedComment = async () => {
              const comments = await github.rest.issues.listComments({
                issue_number: context.payload.pull_request.number,
                owner: context.repo.owner,
                repo: context.repo.repo
              })

              const existingComment = comments.data.find(comment =>
                comment.body.includes(managedMarker)
              )

              if (existingComment) {
                await github.rest.issues.deleteComment({
                  comment_id: existingComment.id,
                  owner: context.repo.owner,
                  repo: context.repo.repo
                })
              }
            }

            // Check for override label — skip all checks if label present
            const labels = context.payload.pull_request.labels.map(l => l.name)
            if (labels.includes('tag: override-groovy-enforcement')) {
              await deleteManagedComment()
              console.log('tag: override-groovy-enforcement label detected — skipping all checks.')
              return
            }

            // Get all files changed in this PR
            const allFiles = await github.paginate(github.rest.pulls.listFiles, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.payload.pull_request.number
            })

            // Fail if the PR introduces any new .groovy file
            // "renamed" only counts when the previous filename was not already Groovy.
            const introducedGroovy = allFiles.filter(file => {
              if (!file.filename.endsWith('.groovy')) {
                return false
              }

              if (file.status === 'added' || file.status === 'copied') {
                return true
              }

              return file.status === 'renamed' &&
                (!file.previous_filename || !file.previous_filename.endsWith('.groovy'))
            })

            // Fetch existing comments once
            const comments = await github.rest.issues.listComments({
              issue_number: context.payload.pull_request.number,
              owner: context.repo.owner,
              repo: context.repo.repo
            })

            const existingComment = comments.data.find(comment => comment.body.includes(managedMarker))

            if (introducedGroovy.length > 0) {
              const fileList = introducedGroovy
                .map(({ filename }) => `- \`${filename}\``)
                .join('\n')
              const body = `**❌ New Groovy Files Detected**\n\n` +
                `Please avoid introducing new \`.groovy\` files to this repository.\n\n` +
                `${fileList}\n\n` +
                `Instead, rewrite the new file(s) in Java / JUnit. See the [How to Test With JUnit Guide](https://github.com/DataDog/dd-trace-java/blob/master/docs/how_to_test_with_junit.md) for more details.\n\n` +
                `If this PR needs an exception, add the \`tag: override-groovy-enforcement\` label to bypass this workflow.\n\n` +
                managedMarker
              if (existingComment) {
                await github.rest.issues.updateComment({
                  comment_id: existingComment.id,
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  body
                })
              } else {
                await github.rest.issues.createComment({
                  issue_number: context.payload.pull_request.number,
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  body
                })
              }
            } else if (existingComment) {
              await github.rest.issues.deleteComment({
                comment_id: existingComment.id,
                owner: context.repo.owner,
                repo: context.repo.repo
              })
            }

            if (introducedGroovy.length > 0) {
              core.setFailed(`${introducedGroovy.length} new Groovy file(s) detected. See PR comment for details. To bypass this workflow, add the 'tag: override-groovy-enforcement' label.`)
            }