bundle-analysis.yml

name: Bundle Analysis

on:
  pull_request:
    branches: [main]
    paths:
      - 'src/**'
      - 'package.json'
      - 'pnpm-lock.yaml'
      - 'tsconfig.json'

permissions:
  contents: read
  pull-requests: write

jobs:
  analyze:
    name: Analyze Bundle Size
    runs-on: ubuntu-latest
    steps:
      - name: Checkout PR
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6

      - name: Checkout base
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
        with:
          ref: ${{ github.base_ref }}
          path: base

      - name: Setup pnpm
        uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v4

      - name: Setup Node.js
        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6
        with:
          node-version: '20'
          cache: 'pnpm'

      - name: Install and build PR
        run: |
          set -euo pipefail
          pnpm install --frozen-lockfile
          if ! pnpm build; then
            echo "::error::PR build failed"
            exit 1
          fi
          if [ ! -d "dist" ]; then
            echo "::error::dist directory not found after build"
            exit 1
          fi

      - name: Install and build base
        run: |
          set -euo pipefail
          cd base
          # For base comparison, don't use frozen-lockfile as it may be out of sync
          if [ -f "pnpm-lock.yaml" ]; then
            pnpm install --no-frozen-lockfile
          elif [ -f "package-lock.json" ]; then
            npm ci
          else
            pnpm install
          fi
          if ! pnpm build 2>/dev/null && ! npm run build 2>/dev/null; then
            echo "::error::Base build failed"
            exit 1
          fi
          if [ ! -d "dist" ]; then
            echo "::error::base/dist directory not found after build"
            exit 1
          fi

      - name: Compare bundle sizes
        id: compare
        run: |
          set -euo pipefail

          # Get PR bundle size
          PR_SIZE=$(du -sb dist | cut -f1)
          PR_SIZE_KB=$(echo "scale=2; $PR_SIZE / 1024" | bc)

          # Get base bundle size
          BASE_SIZE=$(du -sb base/dist | cut -f1)
          BASE_SIZE_KB=$(echo "scale=2; $BASE_SIZE / 1024" | bc)

          # Calculate difference with divide-by-zero protection
          DIFF=$((PR_SIZE - BASE_SIZE))
          DIFF_KB=$(echo "scale=2; $DIFF / 1024" | bc)

          if [ "$BASE_SIZE" -eq 0 ]; then
            DIFF_PERCENT="N/A"
          else
            DIFF_PERCENT=$(echo "scale=2; ($DIFF / $BASE_SIZE) * 100" | bc 2>/dev/null || echo "0")
          fi

          # Get bundle breakdown for PR comment
          BUNDLE_BREAKDOWN=$(du -sh dist/* 2>/dev/null || echo "No files in dist/")

          echo "pr_size=$PR_SIZE_KB" >> $GITHUB_OUTPUT
          echo "base_size=$BASE_SIZE_KB" >> $GITHUB_OUTPUT
          echo "diff=$DIFF_KB" >> $GITHUB_OUTPUT
          echo "diff_percent=$DIFF_PERCENT" >> $GITHUB_OUTPUT

          # Use heredoc for multiline output
          {
            echo 'bundle_breakdown<<EOF'
            echo "$BUNDLE_BREAKDOWN"
            echo 'EOF'
          } >> $GITHUB_OUTPUT

          # Determine status emoji
          if [ "$DIFF" -gt 51200 ]; then
            echo "status=:warning:" >> $GITHUB_OUTPUT
          elif [ "$DIFF" -lt 0 ]; then
            echo "status=:white_check_mark:" >> $GITHUB_OUTPUT
          else
            echo "status=:heavy_check_mark:" >> $GITHUB_OUTPUT
          fi

      - name: Comment on PR
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
        with:
          script: |
            const { owner, repo } = context.repo;
            const prSize = '${{ steps.compare.outputs.pr_size }}';
            const baseSize = '${{ steps.compare.outputs.base_size }}';
            const diff = '${{ steps.compare.outputs.diff }}';
            const diffPercent = '${{ steps.compare.outputs.diff_percent }}';
            const status = '${{ steps.compare.outputs.status }}';
            const bundleBreakdown = `${{ steps.compare.outputs.bundle_breakdown }}`;

            const table = [
              '| Metric | Value |',
              '|--------|-------|',
              `| **Base** | ${baseSize} KB |`,
              `| **PR** | ${prSize} KB |`,
              `| **Diff** | ${diff} KB (${diffPercent}%) |`
            ].join('\n');

            const body = [
              `## ${status} Bundle Size Analysis`,
              '',
              table,
              '',
              '<details>',
              '<summary>Bundle breakdown</summary>',
              '',
              '```',
              bundleBreakdown,
              '```',
              '',
              '</details>'
            ].join('\n');

            // Find existing comment
            const comments = await github.rest.issues.listComments({
              owner,
              repo,
              issue_number: context.issue.number,
            });

            const botComment = comments.data.find(c =>
              c.user.type === 'Bot' && c.body.includes('Bundle Size Analysis')
            );

            if (botComment) {
              await github.rest.issues.updateComment({
                owner,
                repo,
                comment_id: botComment.id,
                body
              });
            } else {
              await github.rest.issues.createComment({
                owner,
                repo,
                issue_number: context.issue.number,
                body
              });
            }