pnpm/.github/workflows/benchmark.yml

name: Benchmarks

on:
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'PR number to benchmark (works with fork PRs too)'
        required: false
        default: ''
        type: string
      runs:
        description: 'Number of benchmark runs per scenario'
        required: false
        default: '10'
        type: string
      warmup:
        description: 'Number of warmup runs before timing'
        required: false
        default: '1'
        type: string

permissions:
  contents: read
  pull-requests: write

jobs:
  benchmark:
    name: Run Benchmarks
    runs-on: ubuntu-latest
    timeout-minutes: 180

    steps:
    - name: Checkout
      uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        fetch-depth: 0
        persist-credentials: false

    - name: Checkout PR head
      if: inputs.pr_number != ''
      env:
        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        PR_NUMBER: ${{ inputs.pr_number }}
      run: |
        echo "Fetching PR #$PR_NUMBER head..."
        git fetch origin "refs/pull/${PR_NUMBER}/head:refs/remotes/origin/pr-${PR_NUMBER}"
        git checkout "origin/pr-${PR_NUMBER}"
        echo "Checked out PR #$PR_NUMBER at $(git rev-parse --short HEAD)"

    - name: Install pnpm and Node
      uses: pnpm/setup@b1cac37306e39c21283b9dd6cb0ac288fb35ba6b
      with:
        runtime: node@26.0.0

    - name: Install hyperfine
      run: |
        wget -q https://github.com/sharkdp/hyperfine/releases/download/v1.18.0/hyperfine_1.18.0_amd64.deb
        sudo dpkg -i hyperfine_1.18.0_amd64.deb

    - name: Compile
      run: pnpm run compile

    - name: Run benchmarks
      id: bench
      continue-on-error: true
      run: |
        set -o pipefail
        ./benchmarks/bench.sh 2>&1 | tee bench-output.txt
        BENCH_DIR=$(grep "Temp directory kept at:" bench-output.txt | sed 's/Temp directory kept at: //')
        echo "bench_dir=$BENCH_DIR" >> "$GITHUB_OUTPUT"
      env:
        RUNS: ${{ inputs.runs }}
        WARMUP: ${{ inputs.warmup }}

    - name: Comment on PR
      if: steps.bench.outputs.bench_dir != ''
      env:
        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        BENCH_DIR: ${{ steps.bench.outputs.bench_dir }}
        INPUT_PR_NUMBER: ${{ inputs.pr_number }}
        REF_NAME: ${{ github.ref_name }}
        RUN_ID: ${{ github.run_id }}
        SERVER_URL: ${{ github.server_url }}
        REPO: ${{ github.repository }}
        RUNS: ${{ inputs.runs }}
        ACTOR: ${{ github.actor }}
      run: |
        RESULTS_FILE="$BENCH_DIR/results.md"

        if [ ! -f "$RESULTS_FILE" ]; then
          echo "::warning::Results file not found at $RESULTS_FILE"
          exit 0
        fi

        echo "--- Benchmark Results ---"
        cat "$RESULTS_FILE"
        echo "-------------------------"

        if [ -n "$INPUT_PR_NUMBER" ]; then
          PR_NUMBER="$INPUT_PR_NUMBER"
        else
          PR_NUMBER=$(gh pr list --head "$REF_NAME" --json number --jq '.[0].number' 2>/dev/null || echo "")
        fi

        if [ -z "$PR_NUMBER" ]; then
          echo "::notice::No open PR found for branch $REF_NAME. Results printed above."
          exit 0
        fi

        MARKER="<!-- pnpm-benchmark-results -->"
        {
          echo "$MARKER"
          cat "$RESULTS_FILE"
          echo ""
          echo "_Run [${RUN_ID}](${SERVER_URL}/${REPO}/actions/runs/${RUN_ID}) · ${RUNS} runs per scenario · triggered by @${ACTOR}_"
        } > /tmp/comment-body.md

        COMMENT_ID=$(gh api "repos/${REPO}/issues/${PR_NUMBER}/comments" \
          --jq "[.[] | select(.body | startswith(\"$MARKER\"))] | .[0].id // empty" 2>/dev/null || echo "")

        if [ -n "$COMMENT_ID" ]; then
          echo "Updating existing benchmark comment $COMMENT_ID on PR #$PR_NUMBER"
          gh api "repos/${REPO}/issues/comments/${COMMENT_ID}" \
            -X PATCH \
            -F "body=@/tmp/comment-body.md"
        else
          echo "Creating new benchmark comment on PR #$PR_NUMBER"
          gh pr comment "$PR_NUMBER" --body-file /tmp/comment-body.md
        fi