prepare-patch-release.yml

name: Prepare patch release
on:
  workflow_dispatch:

permissions:
  contents: read

jobs:
  prepare-patch-release:
    permissions:
      contents: write  # required for pushing changes
      pull-requests: write # required for adding labels to PRs
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install dependencies
        run: pip install toml towncrier

      - run: |
          if [[ ! $GITHUB_REF_NAME =~ ^release/v[0-9]+\.[0-9]+\.x-0\.[0-9]+bx$ ]]; then
            echo this workflow should only be run against long-term release branches
            exit 1
          fi

      - name: Set environment variables
        run: |
          stable_version=$(./scripts/eachdist.py version --mode stable)
          unstable_version=$(./scripts/eachdist.py version --mode prerelease)

          if [[ $stable_version =~ ^([0-9]+\.[0-9]+)\.([0-9]+)$ ]]; then
            stable_major_minor="${BASH_REMATCH[1]}"
            stable_patch="${BASH_REMATCH[2]}"
          else
            echo "unexpected stable_version: $stable_version"
            exit 1
          fi

          if [[ $unstable_version =~ ^0\.([0-9]+)b([0-9]+)$ ]]; then
            unstable_minor="${BASH_REMATCH[1]}"
            unstable_patch="${BASH_REMATCH[2]}"
          else
            echo "unexpected unstable_version: $unstable_version"
            exit 1
          fi

          stable_version_prev="$stable_major_minor.$((stable_patch))"
          unstable_version_prev="0.${unstable_minor}b$((unstable_patch))"
          stable_version="$stable_major_minor.$((stable_patch + 1))"
          unstable_version="0.${unstable_minor}b$((unstable_patch + 1))"

          echo "STABLE_VERSION=$stable_version" >> $GITHUB_ENV
          echo "UNSTABLE_VERSION=$unstable_version" >> $GITHUB_ENV
          echo "STABLE_VERSION_PREV=$stable_version_prev" >> $GITHUB_ENV
          echo "UNSTABLE_VERSION_PREV=$unstable_version_prev" >> $GITHUB_ENV

      - name: Update version
        run: .github/scripts/update-version-patch.sh $STABLE_VERSION $UNSTABLE_VERSION $STABLE_VERSION_PREV $UNSTABLE_VERSION_PREV

      - name: Generate changelog
        run: towncrier build --yes --version "$STABLE_VERSION/$UNSTABLE_VERSION"

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

      - uses: actions/create-github-app-token@df432ceedc7162793a195dd1713ff69aefc7379e # v2.0.6
        id: otelbot-token
        with:
          app-id: ${{ vars.OTELBOT_APP_ID }}
          private-key: ${{ secrets.OTELBOT_PRIVATE_KEY }}

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

          git commit -a -m "$message"
          git push origin HEAD:$branch
          pr_url=$(gh pr create --title "[$GITHUB_REF_NAME] $message" \
                       --body "$message." \
                       --head $branch \
                       --base $GITHUB_REF_NAME)

          echo "pr_url=$pr_url" >> $GITHUB_OUTPUT
      - name: Add prepare-release label to PR
        if: steps.create_pr.outputs.pr_url != ''
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh pr edit ${{ steps.create_pr.outputs.pr_url }}  --add-label "prepare-release"

      - uses: actions/checkout@v4
        with:
          ref: main

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

      - name: Backport patch release changelog to main
        id: backport_pr
        env:
          GITHUB_TOKEN: ${{ steps.otelbot-token.outputs.token }}
        run: |
          release_branch="otelbot/prepare-release-${STABLE_VERSION}-${UNSTABLE_VERSION}"
          message="Backport ${STABLE_VERSION}/${UNSTABLE_VERSION} changelog"
          body="Backport \`${STABLE_VERSION}/${UNSTABLE_VERSION}\` changelog"
          branch="otelbot/backport-changelog-from-${STABLE_VERSION}-${UNSTABLE_VERSION}"

          git fetch origin $release_branch

          # Copy the updated CHANGELOG.md from the release branch
          git checkout FETCH_HEAD -- CHANGELOG.md
          git commit -m "$message"

          git push origin HEAD:$branch
          pr_url=$(gh pr create --title "$message" \
                                --body "$body" \
                                --head $branch \
                                --base main)
          echo "pr_url=$pr_url" >> $GITHUB_OUTPUT

      - name: Add Skip Changelog label to backport PR
        if: steps.backport_pr.outputs.pr_url != ''
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh pr edit ${{ steps.backport_pr.outputs.pr_url }} --add-label "Skip Changelog"