Bug MissingReferenceException after exiting play mode

The game I am working on works fine in playmode. No errors during playing.
But after I exit play mode I get this error:

MissingReferenceException: The object of type 'FieldOfView' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
FieldOfView.HandleNPCDestroyed (UnityEngine.GameObject destroyedNPC) (at Assets/Scripts/FieldOfView.cs:90)
NPC.OnDestroy () (at Assets/Scripts/NPC.cs:34)

As I said all works fine and I only get this error after exiting play mode. It is just anoying and I would like to get rid of the error.
FieldOfView Component thats attached to the NPC never gets destroyed, disabled or anything like that.

 

Does it respawn, is it reset at some point during play mode?

 

if you have time pls look over it, would be much appreciated.
this is the npc:

Code (CSharp):

1. using System;
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using System.Linq;
6. using Unity.VisualScripting;
7. using UnityEngine.AI;
8. using TMPro;
9.  
10. public class NPC : MonoBehaviour
11. {
12.     public Resources resources = new();
13.     public Emotions emotions = new();
14.     public List<AIActionBase> AIActionsBases = new();
15.     public BrainDatabase brainDatabase = new();
16.     public TextMeshProUGUI thinkingText;
17.  
18.     public ColorGroup colorGroup;
19.  
20.     public enum LifeState
21.     {
22.         ON,
23.         OFF,
24.         DEAD
25.     }
26.     public LifeState lifeState;
27.     public event Action<GameObject> OnNPCDestroyed;
28.     public NavMeshAgent agent;
29.  
30.     private void OnDestroy()
31.     {
32.         OnNPCDestroyed?.Invoke(this.gameObject);
33.     }
34.  
35.  
36.     private void Start()
37.     {
38.         agent = GetComponent<NavMeshAgent>();
39.         AddAIActions();
40.         InvokeRepeating(nameof(EnergyTick), 0, 1); //starts energy decline
41.         InvokeRepeating(nameof(MakeADecision), 0, 0.2f);
42.     }
43.  
44.     public void MakeADecision()
45.     {
46.         foreach (AIActionBase action in AIActionsBases)
47.         {
48.             action.UpdateScore();
49.         }
50.         ChooseAction();
51.     }
52.  
53.     public void ChooseAction()
54.     {
55.         AIActionsBases = AIActionsBases.OrderByDescending(x => x.score).ToList();
56.         AIActionsBases.FirstOrDefault().enabled = true;
57.         thinkingText.text = AIActionsBases.FirstOrDefault().actionName;
58.         foreach (AIActionBase action in AIActionsBases.Skip(1))
59.         {
60.             action.enabled = false;
61.         }
62.     }
63.  
64.     private void AddAIActions()
65.     {
66.         AIActionsBases.Add(this.AddComponent<WanderingAI>());
67.         AIActionsBases.Add(this.AddComponent<GatherEnergyAI>());
68.         foreach (AIActionBase aIActionBase in AIActionsBases)
69.         {
70.             aIActionBase.enabled = false;
71.         }
72.     }
73.  
74.     private void EnergyTick()
75.     {
76.         if (lifeState == LifeState.ON)
77.         {
78.             resources.energy -= 1;
79.             if (resources.energy <= 0)
80.             {
81.                 resources.energy = 0;
82.                 lifeState = LifeState.OFF;
83.             }
84.         }
85.         else if (lifeState == LifeState.OFF)
86.         {
87.             if (resources.energy > 0)
88.             {
89.                 lifeState = LifeState.ON;
90.             }
91.         }
92.     }
93. }
94.  

this is the FieldOfView:

Code (CSharp):

1. using System;
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using System.Linq;
6. using static UnityEngine.GraphicsBuffer;
7.  
8. public class FieldOfView : MonoBehaviour
9. {
10.     public float radius;
11.     public float angle;
12.  
13.     public LayerMask targetMask;
14.     public LayerMask obstructionMask;
15.  
16.     public NPC npc;
17.  
18.     private void Start()
19.     {
20.         npc = GetComponent<NPC>();
21.         StartCoroutine(FOVRoutine());
22.     }
23.  
24.     private IEnumerator FOVRoutine()
25.     {
26.         WaitForSeconds wait = new(0.2f);
27.         while (true)
28.         {
29.             yield return wait;
30.             FieldOfViewCheck();
31.         }
32.     }
33.  
34.     private void FieldOfViewCheck()
35.     {
36.         Collider[] rangeChecks = Physics.OverlapSphere(transform.position, radius, targetMask);
37.         if (rangeChecks.Length > 0)
38.         {
39.             foreach (Collider c in rangeChecks)
40.             {
41.                 Transform target = c.transform;
42.                 Vector3 directionToTarget = (target.position - transform.position).normalized;
43.                 if (Vector3.Angle(transform.forward, directionToTarget) < angle / 2)
44.                 {
45.                     float distanceToTarget = Vector3.Distance(transform.position, target.position);
46.                     if (!Physics.Raycast(transform.position, directionToTarget, distanceToTarget, obstructionMask))
47.                     {
48.                         if (target.gameObject.layer == LayerMask.NameToLayer("NPC"))
49.                         {
50.                             if (target.gameObject != this.gameObject)
51.                             {
52.                                 npc.brainDatabase.npcs.Remove(npc.brainDatabase.npcs.Where(x => x.gameObject == target.gameObject).FirstOrDefault());
53.                                 npc.brainDatabase.npcs.Add(new BrainData { gameObject = target.gameObject, lastSeenPosition = target.transform });
54.                                 target.gameObject.GetComponent<NPC>().OnNPCDestroyed += HandleNPCDestroyed;
55.                             }
56.                         }
57.                         else
58.                         {
59.                             npc.brainDatabase.objects.Remove(npc.brainDatabase.objects.Where(x => x.gameObject == target.gameObject).FirstOrDefault());
60.                             npc.brainDatabase.objects.Add(new BrainData { gameObject = target.gameObject, lastSeenPosition = target.transform });
61.                             target.gameObject.GetComponent<ObjectBaseComponent>().OnObjectDestroyed += HandleObjectDestroyed;
62.                         }
63.                     }
64.                 }
65.             }
66.         }
67.     }
68.  
69.     private void HandleObjectDestroyed(GameObject destroyedObject)
70.     {
71.         npc.brainDatabase.objects.Remove(npc.brainDatabase.objects.Where(x => x.gameObject == destroyedObject).FirstOrDefault());
72.         Searching.SetNewWalkPosition(this.transform, Searching.wanderRadius, npc.agent);
73.     }
74.  
75.     private void HandleNPCDestroyed(GameObject destroyedNPC)
76.     {
77.         npc.brainDatabase.npcs.Remove(npc.brainDatabase.npcs.Where(x => x.gameObject == destroyedNPC).FirstOrDefault());
78.         Searching.SetNewWalkPosition(this.transform, Searching.wanderRadius, npc.agent);
79.     }
80. }
81.  

the error lines are not correct anymore: MissingReferenceException: The object of type 'FieldOfView' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
FieldOfView.HandleNPCDestroyed (UnityEngine.GameObject destroyedNPC) (at Assets/Scripts/FieldOfView.cs:90)
NPC.OnDestroy () (at Assets/Scripts/NPC.cs:34)

aka line 90 and 34, since i removed a whole lot of comments

 

the updated error with the correct lines:
MissingReferenceException: The object of type 'FieldOfView' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
FieldOfView.HandleNPCDestroyed (UnityEngine.GameObject destroyedNPC) (at Assets/Scripts/FieldOfView.cs:78)
NPC.OnDestroy () (at Assets/Scripts/NPC.cs:32)

 

OK thanks, didnt know exiting play mode would call onDestroy on all gameobjects.
So I unsubscribed in the OnDestroy method and all is good again:

Code (CSharp):

1. private void OnDestroy()
2.     {
3.         foreach (BrainData npcData in npc.brainDatabase.npcs)
4.         {
5.             npcData.gameObject.GetComponent<NPC>().OnNPCDestroyed -= HandleNPCDestroyed;
6.         }
7.         foreach (BrainData objectData in npc.brainDatabase.objects)
8.         {
9.             objectData.gameObject.GetComponent<ObjectBaseComponent>().OnObjectDestroyed -= HandleObjectDestroyed;
10.         }
11.     }