.github/workflows/outside_collaborator.yaml

name: Outside Collaborator

on:
  pull_request_target:
    types:
      - opened
      - reopened

concurrency:
  group: '${{ github.workflow }}-${{ github.event_name }} @ ${{ github.event.pull_request.number || github.sha }}'
  cancel-in-progress: true

jobs:
  assign-reviewer:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
    - name: Check if PR author is outside collaborator
      env:
        PR_AUTHOR_LOGIN: ${{ github.event.pull_request.user.login }}
        REPO_NAME: ${{ github.event.repository.full_name }}
        PR_NUMBER: ${{ github.event.number }}
      run: |
        PERMISSION_LEVEL=$(curl -s -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" \
          "https://api.github.com/repos/$REPO_NAME/collaborators/$PR_AUTHOR_LOGIN/permission" | jq -r .role_name)

        if [ "$PERMISSION_LEVEL" == "none" ] || [ "$PERMISSION_LEVEL" == "read" ]; then
          echo "PR author is an outside collaborator. Adding label..."

          curl -s -X POST -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" \
            -H "Accept: application/vnd.github.v3+json" \
            -d '["outside collaborator"]' \
            "https://api.github.com/repos/$REPO_NAME/issues/$PR_NUMBER/labels"
        fi