I mean, yeah, I wrote it kind of humorously up there, but I do actually think state diagrams are a good idea and modelling the known error paths is part of real software engineering.

However, I’ve never been in a project where anyone knew nearly enough about what we’re supposed to build, to be able to draw a state diagram before we got started. We would rather do a refactoring halfway through and then we would design a state machine to fit the requirements…