automatic-release-to-main-merger.yml

name: Automatic main branch merger
on:
  # whenever a pull request is merged into a release branch,
  # open a pull request to merge changes down to the main branch
  pull_request:
    branches:
    - '[0-9]+.[0-9]+.x'
    # Don't merge 2.8.x into main
    - '!2.8.x'
    # Don't merge 3.0, 3.1 and 3.2 into main
    - '!3.0.x'
    - '!3.1.x'
    - '!3.2.x'

    types:
    # means that the PR is closed, we still have to check if it was merged
    - closed

env:
  # keep this in sync with the automatic-pr-approver workflow
  LABEL_TYPE: type:release-branch-port
  LABEL_STATUS: status:ready-to-merge

jobs:
  update_merge_pr:
    runs-on: ubuntu-22.04

    # only run this workflow if a pull request has been merged
    if: github.event.pull_request.merged == true

    steps:
      - name: Checkout git repository 🕝
        uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c

      - name: Fetch git tags 🎨
        # see https://github.com/actions/checkout/issues/206#issuecomment-617937725
        run: git fetch --prune --unshallow --tags

      - name: Get branch name ✍️
        id: get-branch-name
        run: |
          GITHUB_BRANCH=${GITHUB_REF/refs\/heads\//}
          echo "release_branch=${GITHUB_BRANCH}" >> $GITHUB_OUTPUT
          echo "new_branch=merge-${GITHUB_BRANCH}-main-${GITHUB_SHA:0:7}" >> $GITHUB_OUTPUT

      - name: Get GitHub labels 🏷
        id: get-github-labels
        run: |
          LATEST_RASA_MINOR=$(git tag --list | grep -P '^\d+\.\d+\.\d+$' | tail -n1 | sed -e 's/.\([0-9]\)*$/.0/g')
          echo "Latest minor: ${LATEST_RASA_MINOR}"
          # bash doesn't support nested variable access
          CURRENT_RASA_MINOR=${GITHUB_REF/refs\/heads\//}
          CURRENT_RASA_MINOR=${CURRENT_RASA_MINOR/\.x/\.0}

          if [[ ${LATEST_RASA_MINOR} == ${CURRENT_RASA_MINOR} ]]
          then
            echo "labels=${LABEL_TYPE},${LABEL_STATUS}" >> $GITHUB_OUTPUT
          else
            echo "labels=${LABEL_TYPE}" >> $GITHUB_OUTPUT
          fi

      - name: Create new branch 🐣
        id: create-new-branch
        if: always()
        uses: peterjgrainger/action-create-branch@64aa569aea81305305c6e92bd236d8c427debff8
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          branch: ${{ steps.get-branch-name.outputs.new_branch }}

      - name: Notify Slack if creating a new branch failed 💬
        if: ${{ failure() && steps.create-new-branch.conclusion == 'failure' }}
        env:
          SLACK_WEBHOOK: ${{ secrets.SLACK_INFRASTRUCTURE_SQUAD_MONITORS_WEBHOOK_URL }}
        uses: Ilshidur/action-slack@689ad44a9c9092315abd286d0e3a9a74d31ab78a
        with:
          args: "🚨 There was a problem with creating a new branch containing commits from the ${{ env.RELEASE_BRANCH }} release branch. Check out the Github action: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}"

      - name: Open pull request ☄️
        if: ${{ steps.create-new-branch.conclusion == 'success' }}
        uses: repo-sync/pull-request@7e79a9f5dc3ad0ce53138f01df2fad14a04831c5
        with:
          # using this token to make sure it triggers other actions
          github_token: ${{ secrets.RASABOT_GITHUB_TOKEN }}
          source_branch: ${{ steps.get-branch-name.outputs.new_branch }}
          destination_branch: main
          pr_title: Merge ${{ steps.get-branch-name.outputs.release_branch }} into main
          pr_template: .github/PULL_REQUEST_AUTOMATIC_TEMPLATE.md
          pr_label: ${{ steps.get-github-labels.outputs.labels }}
          pr_reviewer: ${{ github.event.pull_request.user.login }}

      - name: Close outdated release-merge PRs 🧹
        id: close-outdated-release-merge-prs
        run: |
          # fetch all open merge-PRs that have been opened from the current release branch
          gh pr list -S "is:open label:${LABEL_TYPE} head:merge-${{ steps.get-branch-name.outputs.release_branch }}-main" > prs.txt
          less prs.txt

          # delete newly opened PR from the list
          awk '!/${{ steps.get-branch-name.outputs.new_branch }}/' prs.txt > temp && mv temp prs.txt

          # extract the PR ids
          awk '{print $1}' prs.txt > pr_ids.txt

          # close all outdated PRs
          while read id; do
            gh pr close $id -d
          done <pr_ids.txt
        env:
          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}

      - name: Notify Slack when closing of outdated merge-PRs failed 💬
        if: ${{ failure() && steps.close-outdated-release-merge-prs.conclusion == 'failure'}}
        env:
          SLACK_WEBHOOK: ${{ secrets.SLACK_INFRASTRUCTURE_SQUAD_MONITORS_WEBHOOK_URL }}
        uses: Ilshidur/action-slack@689ad44a9c9092315abd286d0e3a9a74d31ab78a
        with:
          args: "🚨 There was a problem with closing outdated release-merge-PRs of the ${{ env.RELEASE_BRANCH }} release branch. Check out the Github action: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }} \
                These release-merge-PRs are currently open: https://github.com/${{ github.repository }}/pulls?q=is%3Aopen+label%3A${{ env.LABEL_TYPE }}+head%3Amerge-${{ steps.get-branch-name.outputs.release_branch }}-main"