name: Guard main branch

on:
  pull_request:
    branches:
      - main
  merge_group:

permissions: {}

# DO NOT RENAME the job's `name:` — it is referenced by GitHub branch
# protection as a required status check on `main`. Renaming silently
# breaks the gate.
jobs:
  guard:
    name: Verify PR source branch
    runs-on: ubuntu-latest
    timeout-minutes: 2
    steps:
      - name: Reject merge_group events
        if: github.event_name == 'merge_group'
        run: |
          echo "::error::Merge queue is not supported for main. Disable merge queue or update this guard."
          exit 1
      - name: Check head branch name
        env:
          HEAD_REF: ${{ github.head_ref }}
          HEAD_REPO: ${{ github.event.pull_request.head.repo.full_name }}
          BASE_REPO: ${{ github.repository }}
        run: |
          echo "PR head repo: $HEAD_REPO"
          echo "PR head branch: $HEAD_REF"
          if [ "$HEAD_REPO" != "$BASE_REPO" ]; then
            echo "::error::PRs to main must originate from the canonical repository ($BASE_REPO), not a fork ($HEAD_REPO). External contributors should open PRs against 'litellm_internal_staging' instead."
            exit 1
          fi
          if [ "$HEAD_REF" = "litellm_internal_staging" ] || [[ "$HEAD_REF" == litellm_hotfix_?* ]]; then
            echo "Allowed source branch."
            exit 0
          fi
          echo "::error::PRs to main must originate from 'litellm_internal_staging' or a 'litellm_hotfix_*' branch. Got: '$HEAD_REF'. If this is a contribution, retarget the PR against 'litellm_internal_staging' instead."
          exit 1