flutter-smell-build-side-effects

To prevent side effects during Flutter widget lifecycle transitions, enforce controller-driven initialization to ensure IO, telemetry, and network calls are mediated by a central controller rather than UI widgets.

Executing network calls in Flutter build causes hard-to-test code because widget lifecycles become fragile when triggering side effects directly during rendering, bypassing controlled controller initialization and guard rails.

The best way to structure controller initialization for Flutter side effects is to create a dedicated controller to mediate asynchronous work, implementing guarded init to prevent side-effectful operations from executing multiple times across lifecycle transitions.

You can keep Flutter widgets pure while managing telemetry and IO operations by moving side-effectful work to a centralized controller during initialization, ensuring widgets remain testable and free from direct side effects.

Controller-driven initialization stops duplicate side effects during widget lifecycle transitions by applying explicit guard rails that prevent IO or asynchronous work from executing multiple times during build and didChangeDependencies.

You should not bypass a central controller for Flutter side effects in projects where IO, telemetry, or network calls occur during rendering, as skipping controller initialization removes guard rails and breaks widget testability.