codspeed.yml

# Per-PR microbenchmarks: runs tests/bench under CodSpeed's simulation mode,
# which counts instructions instead of wall-clock time, so shared-runner noise
# mostly disappears. Results appear as CodSpeed's PR regression report.
#
# Runs with uv directly on the runner, not inside the devcontainer like
# checks.yml: CodSpeed's runner instruments the benchmark process itself
# (valgrind-based) and is documented for the plain-runner pattern; wrapping it
# in a container would hide the process from it. The benchmarks need no
# backing service (see tests/README.md).
name: CodSpeed

on:
  push:
    branches: [main]
  pull_request:
  # Lets CodSpeed trigger runs to seed baseline data.
  workflow_dispatch:

permissions:
  contents: read

jobs:
  benchmarks:
    # renovate: datasource=github-runners depName=ubuntu
    runs-on: ${{ vars.CI_RUNNER || 'ubuntu-24.04' }}
    permissions:
      contents: read
      # OIDC authentication with CodSpeed; the action's token input is only
      # needed for private repositories.
      id-token: write
    steps:
      - name: Check out repository
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          persist-credentials: false

      - name: Install uv
        uses: astral-sh/setup-uv@bec219d24cd3e171d82865faccec33120bb574f4 # v10.1.0
        with:
          enable-cache: true
          # Same minor as the devcontainer's CPython (.devcontainer/Dockerfile's
          # PYTHON_VERSION); otherwise uv picks the runner's newest Python that
          # satisfies requires-python.
          python-version: "3.14"

      - name: Install dependencies
        run: uv sync --locked --all-groups

      - name: Run benchmarks
        uses: CodSpeedHQ/action@821a40cd6c80e3cfe387caf55668287addd808da # v5.5.0
        with:
          mode: simulation
          # pyproject.toml's cache_dir points into the devcontainer's home, which
          # doesn't exist on this bare runner; use the runner's temp dir instead.
          run: uv run pytest tests/bench --no-cov --codspeed -o cache_dir=${{ runner.temp }}/pytest-cache