benchmark.yml

name: Benchmarks

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  benchmark:
    permissions:
      contents: read
    runs-on: ubuntu-latest
    
    steps:
      - uses: actions/checkout@v5

      - name: Set up JDK 17
        uses: actions/setup-java@v5
        with:
          java-version: '17'
          distribution: 'temurin'
          cache: maven

      - name: Run benchmarks
        run: |
          ./mvnw --batch-mode clean test-compile -P benchmark
          ./mvnw --batch-mode -q -P benchmark dependency:build-classpath -DincludeScope=test -Dmdep.outputFile=target/benchmark-classpath.txt
          CLASSPATH="target/test-classes:target/classes:$(< target/benchmark-classpath.txt)"
          java -cp "$CLASSPATH" org.openjdk.jmh.Main -wi 2 -i 3 -f 1 -rf json -rff benchmark-results.json ${JMH_INCLUDE:+-include ${JMH_INCLUDE}}

      - name: Process benchmark results
        if: always()
        run: |
          if [ -f benchmark-results.json ]; then
            ENTRY_COUNT=$(jq 'length' benchmark-results.json)
            if [ "$ENTRY_COUNT" -eq 0 ]; then
              echo "::error::benchmark-results.json contained no benchmark entries"
              exit 1
            fi
            echo "## Benchmark Results" >> $GITHUB_STEP_SUMMARY
            echo '```' >> $GITHUB_STEP_SUMMARY
          
            # Extract and display results with jq
            jq -r '.[] | "\(.benchmark): \(.primaryMetric.score) ± \(.primaryMetric.scoreError) \(.primaryMetric.scoreUnit)"' benchmark-results.json >> $GITHUB_STEP_SUMMARY
          
            echo '```' >> $GITHUB_STEP_SUMMARY
          
            # Check for performance regressions (fail if any benchmark takes >50ms)
            FAILED=0
            while IFS= read -r line; do
              SCORE=$(echo "$line" | jq -r '.primaryMetric.score')
              BENCHMARK=$(echo "$line" | jq -r '.benchmark')
          
              # Convert to integer for comparison (assuming milliseconds)
              SCORE_INT=$(echo "$SCORE" | cut -d. -f1)
          
              if [ "$SCORE_INT" -gt 50 ]; then
                echo "❌ Performance regression detected in $BENCHMARK: ${SCORE}ms exceeds 50ms threshold" >> $GITHUB_STEP_SUMMARY
                FAILED=1
              fi
            done < <(jq -c '.[]' benchmark-results.json)
          
            if [ "$FAILED" -eq 1 ]; then
              echo "::error::Performance regression detected - one or more benchmarks exceeded the 50ms threshold"
              exit 1
            else
              echo "✅ All benchmarks passed performance thresholds" >> $GITHUB_STEP_SUMMARY
            fi
          else
            echo "::error::No benchmark results found"
            exit 1
          fi

      - name: Upload benchmark results
        if: always()
        uses: actions/upload-artifact@v6
        with:
          name: benchmark-results
          path: benchmark-results.json
          retention-days: 30