production-deployment-create.yml

# Make sure `Settings > Actions > General > Workflow permissions > Read and write permissions` and `Allow GitHub Actions to create and approve pull requests` are enabled

name: Create production deployment

on:
  schedule:
    - cron: "0 0 * * *"
  workflow_dispatch:

jobs:
  create_pull_request:
    runs-on: ubuntu-22.04

    # Related
    # - https://docs.github.com/en/actions/using-jobs/assigning-permissions-to-jobs
    # - https://docs.github.com/en/rest/authentication/permissions-required-for-github-apps
    permissions:
      pull-requests: write # Required for creating a pull request

    steps:
      - uses: actions/github-script@v7.0.1
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          # Related:
          # - https://octokit.github.io/rest.js
          # - https://docs.github.com/en/rest/pulls/pulls
          script: |
            console.info("Fetching existing pull requests")

            const existingPullRequests = await github.rest.pulls.list({
              owner: context.repo.owner,
              repo: context.repo.repo,
              head: "develop",
              base: "main",
              state: "open",
            })

            if (existingPullRequests.data.length > 0) {
              console.info(`Pull request already exists: ${existingPullRequests.data[0].html_url}`)
              return
            }

            console.info("Creating pull request")

            try {
              const createdPullRequest = await github.rest.pulls.create({
                owner: context.repo.owner,
                repo: context.repo.repo,
                head: "develop",
                base: "main",
                title: "Production deployment",
                body: "**Only merge using a merge commit!**"
              })

              console.info(`Pull request created: ${createdPullRequest.html_url}`)
            } catch (error) {
              if (error.response.data.errors[0].message === "No commits between main and develop") {
                console.info("No commits between main and develop")
                return
              }

              throw error
            }