prepare-release-branch.yml

name: Prepare release branch
on:
  workflow_dispatch:

permissions:
  contents: read

jobs:
  prereqs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

      - name: Verify prerequisites
        run: |
          if [[ $GITHUB_REF_NAME != main ]]; then
            echo this workflow should only be run against main
            exit 1
          fi

  create-pull-request-against-release-branch:
    permissions:
      contents: write  # for git push to PR branch
    runs-on: ubuntu-latest
    needs:
      - prereqs
    steps:
      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          # history is needed to allow fast-forward push below in case
          # re-running this workflow after merging additional PRs to main
          fetch-depth: 0

      - name: Create release branch
        run: |
          version=$(.github/scripts/get-version.sh)
          if [[ $version =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)$ ]]; then
            release_branch_name="release/v${version}"
          else
            echo "unexpected version: $version"
            exit 1
          fi

          git push origin HEAD:$release_branch_name

          echo "VERSION=$version" >> $GITHUB_ENV
          echo "RELEASE_BRANCH_NAME=$release_branch_name" >> $GITHUB_ENV

      - name: Update version
        run: sed -Ei "s/val snapshot = true/val snapshot = false/" build.gradle.kts

      - name: Use CLA approved bot
        run: .github/scripts/use-cla-approved-bot.sh

      - uses: actions/create-github-app-token@1b10c78c7865c340bc4f6099eb2f838309f1e8c3 # v3.1.1
        id: otelbot-token
        with:
          app-id: ${{ vars.OTELBOT_APP_ID }}
          private-key: ${{ secrets.OTELBOT_PRIVATE_KEY }}

      - name: Create pull request against the release branch
        env:
          # not using secrets.GITHUB_TOKEN since pull requests from that token do not run workflows
          GH_TOKEN: ${{ steps.otelbot-token.outputs.token }}
        run: |
          message="Prepare release $VERSION"
          branch="otelbot/prepare-release-${VERSION}"

          git checkout -b $branch
          git commit -a -m "$message"
          git push --set-upstream origin $branch
          gh pr create --title "[$RELEASE_BRANCH_NAME] $message" \
                       --body "$message." \
                       --base $RELEASE_BRANCH_NAME