Flag conflicts happen when two (or more) boolean flags are meant to be mutually exclusive but the code allows both to be true. For example “is_pending” and “is_completed” might both be true after a buggy transition, or “lock_held” and “released” might get out of sync. The program is in an inconsistent state that no single line of code “looks” wrong. Stuck states are states that have no valid transition out: you’re in “processing” but there’s no success, failure, or timeout path. Dead branches are code paths that are unreachable after some change — maybe an earlier condition always takes another branch. All of these are structural defects: they’re about the shape of the state space, not a typo.
AI-generated code tends to introduce these because the model adds code incrementally. It adds a new flag for a new feature and doesn’t check that it’s exclusive with an existing one. It adds a new state and forgets to add the transition out. It adds a branch that’s never taken because another branch is always taken first. Tests that only cover happy paths and a few errors won’t catch them. You need either exhaustive testing (often impractical) or a structural view (states, transitions, flags) that you check explicitly.
A simple catalog helps when reviewing: (1) For every flag pair that should be exclusive, is there a guard or an invariant? (2) For every state, is there at least one transition out (including error and timeout)? (3) For every branch, is it reachable under some input? You can do this manually or with tooling. The goal is to make the “AI code debt” — these structural issues — visible and then fix them.
Prevention is better than cleanup: if you have a spec (e.g. a state machine or a list of invariants), generate or write code against it and then verify the implementation matches. The model is good at filling in code; it’s bad at maintaining global consistency. So the catalog is both a review checklist and a design checklist.
Expect more linters and checkers that target flag conflicts, stuck states, and dead branches in generated code.
nJoy 😉