sync-downstream.yml

name: Sync Downstream Integrations

on:
  push:
    branches:
      - main
  workflow_dispatch:
    inputs:
      mode:
        description: Subtree operation mode.
        required: false
        default: pull
        type: choice
        options:
          - pull
          - add

permissions:
  contents: read

jobs:
  sync:
    name: Open downstream sync PR
    runs-on: ubuntu-latest
    env:
      SYNC_TARGET_PATH: ${{ vars.DOWNSTREAM_SYNC_PATH || 'vendor/rusty-red' }}
      SYNC_BRANCH: ${{ vars.DOWNSTREAM_SYNC_BRANCH || 'main' }}
      SYNC_MODE: ${{ inputs.mode || vars.DOWNSTREAM_SYNC_MODE || 'pull' }}
      UPSTREAM_REMOTE: https://github.com/${{ github.repository }}.git
      UPSTREAM_REF: ${{ github.ref_name || 'main' }}
    steps:
      - name: Check downstream sync configuration
        id: config
        env:
          SYNC_REPOSITORY: ${{ vars.DOWNSTREAM_SYNC_REPOSITORY }}
          SYNC_TOKEN: ${{ secrets.DOWNSTREAM_SYNC_TOKEN }}
        run: |
          set -euo pipefail
          if [[ -z "$SYNC_REPOSITORY" || -z "$SYNC_TOKEN" ]]; then
            echo "enabled=false" >> "$GITHUB_OUTPUT"
            echo "Downstream sync is not configured; set DOWNSTREAM_SYNC_REPOSITORY and DOWNSTREAM_SYNC_TOKEN."
            exit 0
          fi
          echo "enabled=true" >> "$GITHUB_OUTPUT"
          echo "repository=$SYNC_REPOSITORY" >> "$GITHUB_OUTPUT"

      - name: Check out upstream
        if: steps.config.outputs.enabled == 'true'
        uses: actions/checkout@v4
        with:
          path: source
          fetch-depth: 0

      - name: Check out downstream
        if: steps.config.outputs.enabled == 'true'
        uses: actions/checkout@v4
        with:
          repository: ${{ steps.config.outputs.repository }}
          token: ${{ secrets.DOWNSTREAM_SYNC_TOKEN }}
          ref: ${{ env.SYNC_BRANCH }}
          path: downstream

      - name: Sync subtree
        if: steps.config.outputs.enabled == 'true'
        working-directory: downstream
        run: |
          set -euo pipefail
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          branch="rusty-red-sync/${GITHUB_SHA::12}"
          git checkout -B "$branch"
          ../source/scripts/sync-downstream-subtree.sh \
            --downstream . \
            --prefix "$SYNC_TARGET_PATH" \
            --remote "$UPSTREAM_REMOTE" \
            --ref "$UPSTREAM_REF" \
            --mode "$SYNC_MODE"
          if git diff --quiet "origin/$SYNC_BRANCH...HEAD"; then
            echo "No downstream sync changes."
            exit 0
          fi
          git push --force-with-lease origin "$branch"

      - name: Open or update downstream PR
        if: steps.config.outputs.enabled == 'true'
        working-directory: downstream
        env:
          GH_TOKEN: ${{ secrets.DOWNSTREAM_SYNC_TOKEN }}
          SYNC_REPOSITORY: ${{ steps.config.outputs.repository }}
        run: |
          set -euo pipefail
          branch="rusty-red-sync/${GITHUB_SHA::12}"
          if ! git ls-remote --exit-code --heads origin "$branch" >/dev/null 2>&1; then
            echo "No sync branch was pushed."
            exit 0
          fi

          body_file="$(mktemp)"
          {
            echo "Syncs Rusty Red upstream changes from ${GITHUB_REPOSITORY}@${GITHUB_SHA}."
            echo
            echo "- Upstream ref: ${UPSTREAM_REF}"
            echo "- Downstream path: ${SYNC_TARGET_PATH}"
            echo "- Mode: ${SYNC_MODE}"
          } > "$body_file"

          title="chore(rusty-red): sync upstream ${GITHUB_SHA::12}"
          if gh pr view "$branch" --repo "$SYNC_REPOSITORY" >/dev/null 2>&1; then
            gh pr edit "$branch" \
              --repo "$SYNC_REPOSITORY" \
              --title "$title" \
              --body-file "$body_file"
          else
            gh pr create \
              --repo "$SYNC_REPOSITORY" \
              --base "$SYNC_BRANCH" \
              --head "$branch" \
              --title "$title" \
              --body-file "$body_file"
          fi