nightly.yml

name: Nightly

# The gate runs Hypothesis derandomised at 300 examples, deliberately: a PR check that flakes is a check
# people learn to ignore. The cost is that every run sees the same inputs, so a rare violation can sit
# there forever. This explores 10,000 randomised examples per property, off the critical path, where a
# failure is a finding rather than a blocked merge.

on:
  schedule:
    - cron: "23 3 * * *"
  workflow_dispatch:

permissions:
  contents: read

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

jobs:
  explore:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          persist-credentials: false

      - name: Install uv
        uses: astral-sh/setup-uv@1c37ad07a6a961277cf70c0d37d6f313000f5884 # v10.3.0
        with:
          enable-cache: false

      - name: Property tests, wide and randomised
        run: uv run --locked pytest --hypothesis-profile=explore -q --no-cov

  # A red nightly is a real property violation, not noise (unlike the Mutation survivors), yet it is off
  # the merge path, so nothing surfaces it - a failure sat unseen for days. On failure open, or bump, a
  # single tracking issue so it is visible without anyone watching the schedule.
  notify:
    needs: explore
    if: failure()
    runs-on: ubuntu-latest
    permissions:
      issues: write
    steps:
      - name: Open or bump the tracking issue
        env:
          GH_TOKEN: ${{ github.token }}
          REPO: ${{ github.repository }}
          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
        run: |
          title="Nightly wide-hypothesis run is failing"
          number=$(gh issue list --repo "$REPO" --state open --search "$title in:title" --json number --jq '.[0].number // empty')
          if [ -n "$number" ]; then
            gh issue comment "$number" --repo "$REPO" --body "Still failing: $RUN_URL"
          else
            gh issue create --repo "$REPO" --title "$title" \
              --body "The scheduled wide Hypothesis run (10k examples) failed - it catches divergences the 300-example gate misses. Run: $RUN_URL"
          fi