benchmark.yml

name: Benchmark

on:
  push:
    branches: [main]
    paths:
      - 'Abies/**'
      - 'Abies.Benchmarks/**'
      - 'scripts/extract-allocations.py'
      - 'scripts/merge-benchmark-results.py'
      - 'scripts/compare-benchmarks.py'
      - '.github/workflows/benchmark.yml'
  pull_request:
    branches: [main]
    paths:
      - 'Abies/**'
      - 'Abies.Benchmarks/**'
      - 'scripts/extract-allocations.py'
      - 'scripts/merge-benchmark-results.py'
      - 'scripts/compare-benchmarks.py'
      - '.github/workflows/benchmark.yml'
  workflow_dispatch:

permissions:
  contents: write
  deployments: write
  pull-requests: write

jobs:
  benchmark:
    name: Run Benchmarks
    runs-on: ubuntu-latest

    steps:
      - name: Checkout PR branch
        uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Need full history for branch comparison

      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          dotnet-version: '10.0.x'

      # ============================================
      # BASELINE BENCHMARKS (main branch)
      # ============================================
      - name: Checkout main branch for baseline
        if: github.event_name == 'pull_request'
        run: |
          git checkout origin/main
          echo "Running baseline benchmarks on main branch..."

      - name: Restore dependencies (baseline)
        if: github.event_name == 'pull_request'
        run: dotnet restore Abies.Benchmarks/Abies.Benchmarks.csproj

      - name: Build benchmarks (baseline)
        if: github.event_name == 'pull_request'
        run: dotnet build Abies.Benchmarks/Abies.Benchmarks.csproj -c Release --no-restore

      - name: Run DOM Diffing benchmarks (baseline)
        if: github.event_name == 'pull_request'
        run: >
          dotnet run --project Abies.Benchmarks -c Release --no-build --
          --filter '*DomDiffingBenchmarks*'
          --exporters json
          --artifacts ./benchmark-baseline/diffing

      - name: Run Rendering benchmarks (baseline)
        if: github.event_name == 'pull_request'
        run: >
          dotnet run --project Abies.Benchmarks -c Release --no-build --
          --filter '*RenderingBenchmarks*'
          --exporters json
          --artifacts ./benchmark-baseline/rendering

      - name: Run Event Handler benchmarks (baseline)
        if: github.event_name == 'pull_request'
        run: >
          dotnet run --project Abies.Benchmarks -c Release --no-build --
          --filter '*EventHandlerBenchmarks*'
          --exporters json
          --artifacts ./benchmark-baseline/handlers

      - name: Merge baseline benchmark results
        if: github.event_name == 'pull_request'
        run: python3 scripts/merge-benchmark-results.py ./benchmark-baseline

      # ============================================
      # PR BENCHMARKS (current PR branch)
      # ============================================
      - name: Checkout PR branch
        if: github.event_name == 'pull_request'
        run: |
          git checkout ${{ github.head_ref }}
          echo "Running PR benchmarks on ${{ github.head_ref }} branch..."

      - name: Restore dependencies (PR)
        run: dotnet restore Abies.Benchmarks/Abies.Benchmarks.csproj

      - name: Build benchmarks (PR)
        run: dotnet build Abies.Benchmarks/Abies.Benchmarks.csproj -c Release --no-restore

      - name: Run DOM Diffing benchmarks (PR)
        run: >
          dotnet run --project Abies.Benchmarks -c Release --no-build --
          --filter '*DomDiffingBenchmarks*'
          --exporters json
          --artifacts ./benchmark-results/diffing

      - name: Run Rendering benchmarks (PR)
        run: >
          dotnet run --project Abies.Benchmarks -c Release --no-build --
          --filter '*RenderingBenchmarks*'
          --exporters json
          --artifacts ./benchmark-results/rendering

      - name: Run Event Handler benchmarks (PR)
        run: >
          dotnet run --project Abies.Benchmarks -c Release --no-build --
          --filter '*EventHandlerBenchmarks*'
          --exporters json
          --artifacts ./benchmark-results/handlers

      - name: Merge PR benchmark results
        run: python3 scripts/merge-benchmark-results.py ./benchmark-results

      # ============================================
      # SAME-JOB COMPARISON (accurate, no runner variance)
      # ============================================
      - name: Compare benchmarks (same-job comparison)
        if: github.event_name == 'pull_request'
        run: |
          python3 scripts/compare-benchmarks.py \
            ./benchmark-baseline/merged \
            ./benchmark-results/merged \
            --throughput-threshold 115 \
            --allocation-threshold 120

      # ============================================
      # HISTORICAL TRACKING (gh-pages, for trends only)
      # ============================================
      - name: Check if gh-pages exists
        id: gh-pages-check
        run: |
          if git ls-remote --exit-code --heads origin gh-pages > /dev/null 2>&1; then
            echo "exists=true" >> $GITHUB_OUTPUT
          else
            echo "exists=false" >> $GITHUB_OUTPUT
          fi

      - name: Store throughput to gh-pages (PR - no fail)
        uses: benchmark-action/github-action-benchmark@v1
        if: github.event_name == 'pull_request' && steps.gh-pages-check.outputs.exists == 'true'
        with:
          name: Rendering Engine Throughput
          tool: benchmarkdotnet
          output-file-path: ./benchmark-results/merged/throughput.json
          github-token: ${{ secrets.GITHUB_TOKEN }}
          auto-push: false
          save-data-file: false
          alert-threshold: '105%'
          comment-on-alert: true
          fail-on-alert: false  # Don't fail here - same-job comparison handles pass/fail
          summary-always: true
          alert-comment-cc-users: '@MCGPPeters'

      - name: Store allocations to gh-pages (PR - no fail)
        uses: benchmark-action/github-action-benchmark@v1
        if: github.event_name == 'pull_request' && steps.gh-pages-check.outputs.exists == 'true'
        with:
          name: Rendering Engine Allocations
          tool: customSmallerIsBetter
          output-file-path: ./benchmark-results/merged/allocations.json
          github-token: ${{ secrets.GITHUB_TOKEN }}
          auto-push: false
          save-data-file: false
          skip-fetch-gh-pages: true
          alert-threshold: '110%'
          comment-on-alert: true
          fail-on-alert: false  # Don't fail here - same-job comparison handles pass/fail
          summary-always: true
          alert-comment-cc-users: '@MCGPPeters'

      - name: Store throughput baseline (main)
        uses: benchmark-action/github-action-benchmark@v1
        if: (github.event_name == 'push' || github.event_name == 'workflow_dispatch') && github.ref == 'refs/heads/main'
        with:
          name: Rendering Engine Throughput
          tool: benchmarkdotnet
          output-file-path: ./benchmark-results/merged/throughput.json
          github-token: ${{ secrets.GITHUB_TOKEN }}
          auto-push: true
          save-data-file: true
          skip-fetch-gh-pages: ${{ steps.gh-pages-check.outputs.exists != 'true' }}
          alert-threshold: '105%'
          comment-on-alert: true
          fail-on-alert: true
          fail-threshold: '110%'
          alert-comment-cc-users: '@MCGPPeters'

      - name: Store allocation baseline (main)
        uses: benchmark-action/github-action-benchmark@v1
        if: (github.event_name == 'push' || github.event_name == 'workflow_dispatch') && github.ref == 'refs/heads/main'
        with:
          name: Rendering Engine Allocations
          tool: customSmallerIsBetter
          output-file-path: ./benchmark-results/merged/allocations.json
          github-token: ${{ secrets.GITHUB_TOKEN }}
          auto-push: true
          save-data-file: true
          skip-fetch-gh-pages: false
          alert-threshold: '110%'
          comment-on-alert: true
          fail-on-alert: true
          fail-threshold: '120%'
          alert-comment-cc-users: '@MCGPPeters'

      - name: Upload benchmark artifacts
        uses: actions/upload-artifact@v4
        if: always()
        with:
          name: benchmark-results
          path: |
            ./benchmark-results/
            ./benchmark-baseline/
          retention-days: 30