Check Formatting workflow (hingston/7-billion-humans-solutions)

The Check Formatting workflow from hingston/7-billion-humans-solutions, explained and optimized by Latchkey.

What it does

This is the Check Formatting workflow from the hingston/7-billion-humans-solutions repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

name: Check Formatting
on:
  pull_request:
jobs:
  Formatting:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ["3.13"]
    steps:
      - uses: actions/checkout@v6.0.2
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v6
        with:
          python-version: ${{ matrix.python-version }}
      - name: Check formatting is correct
        run: python check_names.py

The same workflow, on Latchkey

Estimated ~20% faster on cache hits, plus fewer wasted runs and a safer supply chain. Added and changed lines are highlighted.

name: Check Formatting
on:
  pull_request:
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  Formatting:
    timeout-minutes: 30
    runs-on: latchkey-small
    strategy:
      matrix:
        python-version: ["3.13"]
    steps:
      - uses: actions/checkout@v6.0.2
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v6
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: Check formatting is correct
        run: python check_names.py
 

What changed

• Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
• Cancel superseded runs when a branch or PR gets a newer push.
• Cache dependency installs on the setup step so they are served from cache.
• Add a job timeout so a hung step cannot burn hours of runner time.

This workflow runs 1 job per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow