import prefect


PRETEND_VALIDATION_PASSED = True


def handle_failed_validation(task, old_state, new_state):
    if isinstance(new_state, prefect.engine.state.ValidationFailed):
        return prefect.engine.state.Success(result=new_state.result)
    return new_state


@prefect.task(state_handlers=[handle_failed_validation])
def fail_task():
    class FakeResult:
        success: bool = PRETEND_VALIDATION_PASSED

    if PRETEND_VALIDATION_PASSED:
        return FakeResult()

    raise prefect.engine.signals.VALIDATIONFAIL(result=FakeResult())


@prefect.task()
def check_ge_result(result):
    return result.success


@prefect.task(log_stdout=True)
def log(message):
    print(message)


with prefect.Flow("test") as flow:
    result = fail_task()
    validation_passed = check_ge_result(result)
    with prefect.case(validation_passed, True):
        log("Handle validation success using result")

    with prefect.case(validation_passed, False):
        log("Validation failed, log it or whatever")

flow.run()