EllanJiang/GameFramework · error · GameFrameworkException

FSM ' ' can not change state to ' ' which is not exist.

Error message

FSM '{0}' can not change state to '{1}' which is not exist.

What it means

After confirming a current state, ChangeState(Type) resolves the target via GetState(stateType). If no state of that type is registered in this FSM, it throws GameFrameworkException with "FSM '{0}' can not change state to '{1}' which is not exist.", naming the FSM (TypeNamePair of state type + name) and the missing type's full name.

Solutions

1. Add the target state type to the states array in the Fsm.Create call
2. Correct the ChangeState type argument to a registered state type
3. Audit all transitions after removing/renaming state classes
4. Guard with HasState-style checks or wrap transitions in try-catch during development

Example fix

// before
Fsm<T> fsm = Fsm<T>.Create(name, owner); // no states registered
fsm.ChangeState(typeof(IdleState)); // throws
// after
Fsm<T> fsm = Fsm<T>.Create(name, owner, new IdleState(), new MoveState());
fsm.ChangeState(typeof(IdleState)); // OK

if (fsm.GetState(typeof(TargetState)) == null) throw new InvalidOperationException("Target state not registered in this FSM");

try { fsm.ChangeState(typeof(TargetState)); } catch (GameFrameworkException ex) when (ex.Message.Contains("can not change state to")) { /* fall back to a default state or log missing registration */ }

When it happens

Trigger: Calling fsm.ChangeState(typeof(SomeState)) where SomeState was never included in the states array passed at Fsm creation; typos in the generic type argument; a state registered on a different FSM instance.

Common situations: Adding a new state class but forgetting to add it to the CreateFsm states list; copy-pasted ChangeState calls referencing states from another FSM; refactoring that removed a state while leaving transitions pointing at it.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Current state is invalid.
• FSM is invalid.
• State type is invalid.
• State type ' ' is invalid.
• FSM owner is invalid.

AI-assisted analysis of EllanJiang/GameFramework@d0c010b051 (2026-09-15). Data as JSON: /api/errors/32b8dc94e12cf549. Report an issue: GitHub.

Appendix: source

Thrown at GameFramework/Fsm/Fsm.cs:579

        {
            ChangeState(typeof(TState));
        }

        /// <summary>
        /// 切换当前有限状态机状态。
        /// </summary>
        /// <param name="stateType">要切换到的有限状态机状态类型。</param>
        internal void ChangeState(Type stateType)
        {
            if (m_CurrentState == null)
            {
                throw new GameFrameworkException("Current state is invalid.");
            }

            FsmState<T> state = GetState(stateType);
            if (state == null)
            {
                throw new GameFrameworkException(Utility.Text.Format("FSM '{0}' can not change state to '{1}' which is not exist.", new TypeNamePair(typeof(T), Name), stateType.FullName));
            }

            m_CurrentState.OnLeave(this, false);
            m_CurrentStateTime = 0f;
            m_CurrentState = state;
            m_CurrentState.OnEnter(this);
        }
    }
}

View on GitHub (pinned to d0c010b051)