merge-tests.yml

# Run final tests only when attempting to merge, shown as skipped status checks beforehand
name: Merge group tests

on:
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review]
    branches: [main]
  merge_group:

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

jobs:
  gpu-benchmark:
    # Test working run
    if: github.event_name != 'pull_request' || github.event.action == 'enqueued'
    name: Run fibonacci bench
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      # Install dependencies
      - uses: actions-rs/toolchain@v1
      - uses: Swatinem/rust-cache@v2
      - uses: taiki-e/install-action@v2
        with:
          tool: just@1.15
      - name: Install criterion
        run: |
          cargo install cargo-criterion
          cargo install criterion-table
      # Checkout base branch for comparative bench
      - uses: actions/checkout@v4
        with:
          ref: main
          path: main
      # Copy the script so the base can bench with the same parameters
      - name: Copy source script to base branch
        run: cd benches && cp justfile bench.env ../main/benches
      - name: Set base ref variable
        run: cd main && echo "BASE_REF=$(git rev-parse HEAD)" >> $GITHUB_ENV
      - run: echo ${{ env.BASE_REF }}
      - name: Run bench on base branch
        run: cd main/benches && just --dotenv-filename bench.env bench fibonacci
      - name: Copy bench output to PR branch
        run: ls -a && cp main/${{ env.BASE_REF }}.json .
      - name: Run bench on PR branch
        run: ls -a && cd benches && just --dotenv-filename bench.env bench fibonacci
      # Create a `criterion-table` and write in commit comment
      - name: Run `criterion-table`
        run: cat ${{ github.sha }}.json | criterion-table > BENCHMARKS.md
      - name: Write bench on commit comment
        uses: peter-evans/commit-comment@v3
        with:
          body-path: BENCHMARKS.md
      # TODO: Use jq for JSON parsing if needed
      # Check for benchmark regression based on Criterion's configured noise threshold
      - name: Performance regression check
        id: check-regression
        run: |
          echo "regress_count=$(grep -c 'Regressed' ${{ github.sha }}.json)" >> $GITHUB_OUTPUT
      # Fail job if regression found
      - uses: actions/github-script@v6
        if: ${{ steps.check-regression.outputs.regress_count }} > 0
        with:
          script: |
            core.setFailed('Fibonacci bench regression detected')