Sorbet + 100% cov makes Ruby refactoring possible

Last week, we deployed a refactoring patch to our Ruby codebase that was big for us 1 – 178 files changed: Changeset. If you’d asked me five years ago how to safely deploy a change of this size in Ruby, I’d have a very simple answer: you can’t. Ruby’s parser is no help in detecting regressions – it’ll notice invalid syntax, and that’s about it. A good test suite helps, but it’s never complete enou