Collaboration with a large team is challenging, and even more so if it’s on a single codebase, like the Shopify monolith. Shopify changes 40 times a day. We follow a trunk-based development workflow and merge around 400 commits to master daily. There are three rules that govern how we deploy safely, but they were hard to maintain at our growing scale. Soft conflicts broke master, slow deployments caused large drift between master and production, and the time to deploy emergency merges slowed due...