benchmarks-pr-comment.yml

name: Benchmarks PR Comment

# Posts a one-time instruction comment on newly opened PRs so contributors /
# reviewers know how to launch a JMH benchmark run for the PR. The actual
# benchmark workflow lives in `benchmarks.yml` and is triggered by a
# `/benchmark` slash command (collaborators only).

on:
  pull_request_target:
    types: [opened]

permissions:
  pull-requests: write

jobs:
  comment:
    if: startsWith(github.repository, 'ClickHouse/clickhouse-java')
    runs-on: ubuntu-latest
    steps:
      - name: Post benchmark instructions
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh api -X POST \
            "repos/${{ github.repository }}/issues/${{ github.event.pull_request.number }}/comments" \
            -f body="$(cat <<'EOF'
          Repository collaborators can run the JMH benchmark suite against this PR by commenting:

          ```
          /benchmark
          ```

          Optional regression threshold override (Δ% on Time or Alloc/op; defaults to 10%):

          ```
          /benchmark threshold=15
          ```

          Only one benchmark run per PR is active at a time — issuing a new `/benchmark` comment cancels the previous run. After the run finishes a separate comment will be posted comparing it against the latest scheduled run on `main`; the PR check fails if any benchmark regresses by more than the threshold.
          EOF
          )"