ci workflow (google-deepmind/mctx)

The ci workflow from google-deepmind/mctx, explained and optimized by Latchkey.

What it does

This is the ci workflow from the google-deepmind/mctx repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

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

The workflow

name: ci

on:
  push:
    branches: ["main"]
  pull_request:
    branches: ["main"]

jobs:
  build-and-test:
    name: "Python ${{ matrix.python-version }} on ${{ matrix.os }}"
    runs-on: "${{ matrix.os }}"

    strategy:
      matrix:
        python-version: ["3.12", "3.13", "3.14"]
        os: [ubuntu-latest]

    steps:
      - uses: "actions/checkout@v5"
      - uses: "actions/setup-python@v5.3.0"
        with:
            python-version: "${{ matrix.python-version }}"
      - name: Run CI tests
        run: bash test.sh
        shell: bash

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

name: ci
 
on:
  push:
    branches: ["main"]
  pull_request:
    branches: ["main"]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build-and-test:
    timeout-minutes: 30
    name: "Python ${{ matrix.python-version }} on ${{ matrix.os }}"
    runs-on: "${{ matrix.os }}"
 
    strategy:
      matrix:
        python-version: ["3.12", "3.13", "3.14"]
        os: [ubuntu-latest]
 
    steps:
      - uses: "actions/checkout@v5"
      - uses: "actions/setup-python@v5.3.0"
        with:
            python-version: "${{ matrix.python-version }}"
      - name: Run CI tests
        run: bash test.sh
        shell: bash
 

What changed

• Cancel superseded runs when a branch or PR gets a newer push.
• Add a job timeout so a hung step cannot burn hours of runner time.

This workflow runs 1 job (3 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.