sync-develop.yml

name: Sync main into develop

on:
  push:
    tags:
      - 'v*'

jobs:
  sync:
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Open PR from main to develop
        uses: actions/github-script@v7
        with:
          script: |
            const tag = context.ref.replace('refs/tags/', '');
            const { owner, repo } = context.repo;

            // Check if develop branch exists
            try {
              await github.rest.repos.getBranch({ owner, repo, branch: 'develop' });
            } catch (e) {
              if (e.status === 404) {
                core.warning('Branch "develop" not found. Skipping PR creation.');
                return;
              }
              throw e;
            }

            // Check if branches are already in sync
            const comparison = await github.rest.repos.compareCommitsWithBasehead({
              owner,
              repo,
              basehead: 'develop...main',
            });
            if (comparison.data.ahead_by === 0) {
              core.info('Branches are already in sync. No PR needed.');
              return;
            }

            // Check if a PR from main to develop already exists
            const existingPRs = await github.rest.pulls.list({
              owner,
              repo,
              state: 'open',
              head: `${owner}:main`,
              base: 'develop',
            });
            if (existingPRs.data.length > 0) {
              core.info(`PR already exists: ${existingPRs.data[0].html_url}`);
              return;
            }

            await github.rest.pulls.create({
              owner,
              repo,
              title: `chore: sync ${tag} from main into develop`,
              head: 'main',
              base: 'develop',
              body: `Automated back-merge after release ${tag}.`,
            });