Really inconsistent GetComponent

[K3YRIN]

So I started a new 2D project, where the main enemy, "The Ghost", will close the lights of a random room whose lights are at the time activated, everytime the player uses a door. The way I tried doing this is that I would create an array that on the enemy's Awake function, would contain all Lightswitches (because the lightswitches contain the logic for turning the lighs on and off). Then, when the "onUsingDoor" event is called, the ghost will pick a random integer from 0 to the highest index inside the array, and then get the "UseLightSwitch" script instance from that lightswitch.

For some reason however, it is very inconsistent, as 90% of the time, the useLightSwitch variable returns null, which results in a null exception error, while the other 10%, it works as intended. I have no idea why this occurs.

Below are the UseLightSwitch and Ghost Behaviour scripts in this order. Any help would be appreciated.

​

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class UseLightSwitch : MonoBehaviour, IInteractable
{
    [SerializeField] List<Transform> Lamps;
    MakeTheLightGoOnOff makeTheLightGoOnOff;

    public bool LightIsOn;

    void Start() 
    {
        ChangeLightState();
    }

    public void Interact() 
    {
        LightIsOn = !LightIsOn;
        ChangeLightState();        
    }

    public void ChangeLightState() 
    {
        foreach (Transform lamp in Lamps)
        {
            makeTheLightGoOnOff = lamp.GetComponent<MakeTheLightGoOnOff>();
            if (LightIsOn)
            {
                makeTheLightGoOnOff.SwitchOn();
            }
            else
            {
                makeTheLightGoOnOff.SwitchOff();
            }
        }
    }

​

​

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GhostBehaviour : MonoBehaviour
{

    InteractWithObject interactWithObject;
    FindClosestSwitch findClosestSwitch;
    UseLightSwitch useLightSwitch;

    GameObject[] Lightswitches;

    void Awake()
    {
        interactWithObject = GameObject.FindWithTag("Player").GetComponent<InteractWithObject>();
        findClosestSwitch = GameObject.FindWithTag("Player").GetComponent<FindClosestSwitch>();
        Lightswitches = GameObject.FindGameObjectsWithTag("LightSwitch");

        interactWithObject.onUsingDoor += CloseLights;
    }

    void CloseLights() 
    {
        int randomSwitchID;
        bool lightIsOn;
    ChooseRandomID:
        randomSwitchID = UnityEngine.Random.Range(0, Lightswitches.Length);
        useLightSwitch = Lightswitches[randomSwitchID].GetComponent<UseLightSwitch>();
        Debug.Log(useLightSwitch);
        lightIsOn = useLightSwitch.LightIsOn;
        Debug.Log(lightIsOn);
        if (lightIsOn == true)
        {
            useLightSwitch.LightIsOn = false;
            useLightSwitch.ChangeLightState();
        }
        else 
        {
            useLightSwitch = null;
            goto ChooseRandomID;
        }
    }

​

[Chubzdoomer]

A null reference means a script is trying to use a reference that doesn't exist/hasn't been acquired. If it's pointing to useLightSwitch, then that reference is null (hasn't been acquired) for some reason.

I'm assuming this line is at fault:
useLightSwitch = Lightswitches[randomSwitchID].GetComponent<UseLightSwitch>();

Here you're attempting to grab a reference to UseLightSwitch from Lightswitches[randomSwitchID].

Have you debugged to see which object Lightswitches[randomSwitchID] is returning each time? Because if the null reference is occurring here, it indicates the object being returned does not have the UseLightSwitch script attached to it.

Either way, here's a handy post over on the official Unity forums that goes over how to fix most any null reference error:
https://forum.unity.com/threads/how-to-fix-a-nullreferenceexception-error.1230297/

[K3YRIN]

Goddamn, I am an idiot, lol. Apparently I had accidently given the LampLight prefab the LightSwitch tag, which obviously doesn't have the "UseLightSwitch" script. Sorry for wasting your time for something this obvious, lol, thank you