post-release-sync.yml

# This workflow merges release back into main after a successful release run.
# If there are no conflicts, it commits directly and deletes the release branch.
# If there are conflicts, it creates a sync PR for manual resolution.
# Can also be started manually from the Actions tab.

name: 🔁 Post-Release Sync

on:
  workflow_dispatch:
  workflow_run:
    workflows: ["🚀 Release Builder"]
    types: [completed]

permissions:
  contents: write
  pull-requests: write

env:
  SOURCE_BRANCH: "release"
  TARGET_BRANCH: "main"
  RELEASE_GIT_USER_NAME: "thunder-automation-bot"
  RELEASE_GIT_USER_EMAIL: "thunder-bot@wso2.com"

jobs:
  sync-release-to-main:
    name: 🔀 Sync release -> main
    if: ${{ github.event_name == 'workflow_dispatch' || github.event.workflow_run.conclusion == 'success' }}
    runs-on: ubuntu-latest
    steps:
      - name: 📥 Checkout Target Branch
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
        with:
          fetch-depth: 0
          token: ${{ secrets.THUNDER_AUTOMATION_BOT }}
          ref: ${{ env.TARGET_BRANCH }}

      - name: 🔧 Configure Git
        run: |
          git config --local user.name "${{ env.RELEASE_GIT_USER_NAME }}"
          git config --local user.email "${{ env.RELEASE_GIT_USER_EMAIL }}"

      - name: 🔄 Merge Release Branch into Main
        id: merge_sync
        run: |
          set -euo pipefail

          git fetch origin "${SOURCE_BRANCH}" "${TARGET_BRANCH}"
          git checkout "${TARGET_BRANCH}"

          AHEAD=$(git rev-list --count "HEAD..origin/${SOURCE_BRANCH}")
          if [ "${AHEAD}" = "0" ]; then
            echo "✅ ${TARGET_BRANCH} is already up to date with ${SOURCE_BRANCH}. Nothing to sync."
            echo "conflict_detected=false" >> "$GITHUB_OUTPUT"
            echo "merged=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          if ! git merge --no-ff --no-edit "origin/${SOURCE_BRANCH}"; then
            echo "❌ Merge conflict detected while merging ${SOURCE_BRANCH} into ${TARGET_BRANCH}."
            git merge --abort || true
            echo "conflict_detected=true" >> "$GITHUB_OUTPUT"
            echo "merged=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          git push origin "HEAD:${TARGET_BRANCH}"
          echo "✅ Successfully merged ${SOURCE_BRANCH} into ${TARGET_BRANCH}."
          echo "conflict_detected=false" >> "$GITHUB_OUTPUT"
          echo "merged=true" >> "$GITHUB_OUTPUT"

      - name: 🗑️ Delete Release Branch
        if: steps.merge_sync.outputs.merged == 'true'
        run: |
          git push origin --delete "${SOURCE_BRANCH}"
          echo "✅ Deleted '${SOURCE_BRANCH}' branch."

      - name: 🔔 Create Sync PR for Conflict Resolution
        if: steps.merge_sync.outputs.conflict_detected == 'true'
        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
        with:
          script: |
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const base = process.env.TARGET_BRANCH;
            const headBranch = process.env.SOURCE_BRANCH;
            const head = `${owner}:${headBranch}`;
            const runUrl = `${context.serverUrl}/${owner}/${repo}/actions/runs/${context.runId}`;
            const triggerLine = context.eventName === 'workflow_dispatch'
              ? `Triggered manually from Actions: ${runUrl}`
              : `Triggered after successful release workflow run: ${context.payload.workflow_run.html_url}`;

            const existing = await github.rest.pulls.list({
              owner,
              repo,
              state: 'open',
              base,
              head
            });

            if (existing.data.length > 0) {
              const pr = existing.data[0];
              core.info(`Existing sync PR found: #${pr.number} ${pr.html_url}`);
              return;
            }

            const created = await github.rest.pulls.create({
              owner,
              repo,
              title: `Sync ${headBranch} branch back to ${base}`,
              head: headBranch,
              base,
              body: [
                'Automated PR created because post-release sync hit merge conflicts.',
                '',
                `Source branch: ${headBranch}`,
                `Target branch: ${base}`,
                '',
                triggerLine
              ].join('\n')
            });

            core.info(`Created sync PR: #${created.data.number} ${created.data.html_url}`);

            await core.summary
              .addHeading('⚠️ Merge Conflict Detected', 3)
              .addRaw(`Conflicts were found while merging \`${headBranch}\` into \`${base}\`. A pull request has been opened for manual resolution.`)
              .addBreak()
              .addRaw(`**PR:** [#${created.data.number} — ${created.data.title}](${created.data.html_url})`)
              .write();