sync-newsletter.yml

name: '📬 Newsletter · 🔄 Sync from Buttondown'

# =============================================================================
# Newsletter — Sync Buttondown content into dev + main
# =============================================================================
#
# Daily content-only sync. Pulls published emails from Buttondown, commits
# them to dev (so site-preview-dev picks them up), cherry-picks the same
# commit onto main (the stable release branch), and dispatches
# site-publish-live so the post lands on mlsysbook.ai.
#
# Why both branches:
#   - dev is the integration trunk; pushing there auto-triggers
#     site-preview-dev.yml so the dev preview gets the new post.
#   - main is the stable release branch from which gh-pages is published.
#     Newsletter content auto-promotes to main because it's contained to
#     site/newsletter/posts/ and can't conflict with anything else.
#
# Why we dispatch site-publish-live instead of building here:
#   - Single deploy path. Only site-publish-live writes to gh-pages, so the
#     hashed bootstrap CSS in site_libs/ stays in sync with the unified
#     site's about/community HTML by construction.
#   - Past bug: this workflow used to do its own partial deploy of
#     newsletter + site_libs and corrupted /site_libs/ for the about and
#     community pages, because their HTML still referenced the previously
#     deployed bootstrap-{HASH}.css.
#
# Triggers:
#   - Schedule: Daily at 6 AM UTC (1 AM ET)
#   - Manual:   workflow_dispatch
#
# Secrets: BUTTONDOWN_API_KEY, GITHUB_TOKEN
#
# Related:
#   - site/newsletter/cli/  — news CLI (pull subcommand powers this)
#   - site-publish-live.yml — full unified-site deploy from main
#   - site-preview-dev.yml  — auto-triggered by our push to dev
# =============================================================================

on:
  schedule:
    - cron: '0 6 * * *'  # Daily at 6am UTC (1am ET)
  workflow_dispatch: {}

permissions:
  contents: write
  actions: write  # required to dispatch site-publish-live via `gh workflow run`

concurrency:
  group: newsletter-sync
  cancel-in-progress: true

jobs:
  sync:
    name: '📬 Sync Buttondown → dev + main'
    runs-on: ubuntu-latest

    steps:
      - name: 📥 Checkout dev (full history for cherry-pick)
        uses: actions/checkout@v6
        with:
          ref: dev
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: 🐍 Setup Python
        uses: actions/setup-python@v6
        with:
          python-version: ${{ vars.PYTHON_VERSION || '3.12' }}

      - name: 📦 Install news CLI
        run: pip install -r site/newsletter/requirements.txt

      - name: 📬 Pull from Buttondown
        env:
          BUTTONDOWN_API_KEY: ${{ secrets.BUTTONDOWN_API_KEY }}
        run: python3 site/newsletter/bin/news pull

      - name: 📦 Commit new posts to dev
        id: commit_dev
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

          # _stats.yml is gitignored — regenerated fresh on every render by
          # publish-live's `news pull`. We only commit post markdown here.
          git add site/newsletter/posts/
          if git diff --staged --quiet; then
            echo "ℹ️ No new newsletter posts"
            echo "has_new_posts=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          COUNT=$(git diff --staged --name-only | wc -l | tr -d ' ')
          git commit -m "chore: sync $COUNT newsletter post(s) from Buttondown [automated]"

          # Push with retry. Capture SHA *after* successful push because
          # `git pull --rebase` during retry rewrites the local commit's SHA.
          NEWSLETTER_SHA=""
          for i in 1 2 3; do
            if git push origin dev; then
              NEWSLETTER_SHA=$(git rev-parse HEAD)
              echo "✅ Pushed $COUNT post(s) to dev (SHA: $NEWSLETTER_SHA)"
              break
            fi
            echo "⚠️ Push to dev failed (attempt $i/3), rebasing..."
            git pull --rebase origin dev
          done

          if [ -z "$NEWSLETTER_SHA" ]; then
            echo "❌ Push to dev failed after 3 attempts"
            exit 1
          fi

          echo "newsletter_sha=$NEWSLETTER_SHA" >> "$GITHUB_OUTPUT"
          echo "has_new_posts=true" >> "$GITHUB_OUTPUT"

      - name: 🍒 Cherry-pick newsletter commit onto main
        if: steps.commit_dev.outputs.has_new_posts == 'true'
        env:
          NEWSLETTER_SHA: ${{ steps.commit_dev.outputs.newsletter_sha }}
        run: |
          git fetch origin main
          git checkout main
          git reset --hard origin/main

          if ! git cherry-pick "$NEWSLETTER_SHA"; then
            echo "❌ Cherry-pick failed — main and dev have diverged in"
            echo "   site/newsletter/posts/. The newsletter post is safely on"
            echo "   dev (SHA: $NEWSLETTER_SHA). Resolve the divergence and"
            echo "   re-run the workflow."
            git cherry-pick --abort || true
            exit 1
          fi

          for i in 1 2 3; do
            if git push origin main; then
              echo "✅ Cherry-picked newsletter commit onto main"
              break
            fi
            echo "⚠️ Push to main failed (attempt $i/3), rebasing..."
            if ! git pull --rebase origin main; then
              echo "❌ Rebase failed during cherry-pick promotion"
              exit 1
            fi
          done

      - name: 🚀 Dispatch site-publish-live on main
        if: steps.commit_dev.outputs.has_new_posts == 'true'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh workflow run site-publish-live.yml --ref main
          echo "✅ Dispatched site-publish-live on main"
          echo ""
          echo "Watch: https://github.com/${{ github.repository }}/actions/workflows/site-publish-live.yml"

      - name: 📊 Summary
        if: always()
        run: |
          {
            echo "## 📬 Newsletter Sync"
            echo ""
            if [ "${{ steps.commit_dev.outputs.has_new_posts }}" = "true" ]; then
              echo "- ✅ Pulled new post(s) from Buttondown"
              echo "- ✅ Committed to \`dev\` (\`${{ steps.commit_dev.outputs.newsletter_sha }}\`)"
              echo "- ✅ Cherry-picked onto \`main\`"
              echo "- 🚀 Dispatched \`site-publish-live\` on \`main\` — newsletter live in ~5 min"
            else
              echo "No new posts from Buttondown. Nothing to do."
            fi
          } >> "$GITHUB_STEP_SUMMARY"