Detecting whether your package’s API is backwards-compatible is an important problem. You want to know whether your change could break existing users, or whether you’re just adding new features. In this tutorial, I’ll begin by discussing what we mean by API compatibility. I’ll talk about how computing it is harder than it might seem at first, and I’ll describe the algorithm I used to write my apidiff tool. Along the way, I’ll provide tips on how to future-proof your own code against API …