Very odd issue with Data Corruption due to Update Loop, even when no code is running

Unity Engine
1

Hello,

I have recently run into a bizarre issue in code that was previously working fine.

I have a list of a custom class in unity, and I have a system to save it to a Database.

For testing purposes, I run a manual save by setting a flag, like this:

        if (manualsavetodb)
        {
            manualsavetodb = false;

            print("manual save to db:"); //player data only for now
            saveavatarstatetodb();
            saveaistatetodb();
        }

So, the above code is in Update() and I click on “manualsavetodb” in the editor, and the above code runs.

This used to work fine, but now, whenever I run it the list which stores my items becomes corrupted. It seems that they all become uninitialised somehow (I get nullreferenceexceptions), but here is the really weird thing, if I change my code to this:

        if (manualsavetodb)
        {
            manualsavetodb = false;

            //print("manual save to db:"); //player data only for now
            //saveavatarstatetodb();
           // saveaistatetodb();
        }

This issue STILL occurs! Even though I am not actuall calling any functions!

Is this some kind of odd bug within unity? This code seemed to run find before! Not even the print statement is running!

2

I don’t really understand what you’re trying to do, but I’m fairly certain that it isn’t a Unity bug, but you’re making a mistake somewhere. Like duplicating game object with this code, another script with the same database code, or something else.

3

That’s the thing, I’m not doing anything!

This code:

   if (manualsavetodb)
        {
            manualsavetodb = false;
            //print("manual save to db:"); //player data only for now
            //saveavatarstatetodb();
           // saveaistatetodb();
        }

After being run, (even though it does nothing) is causing my list of objects to become null references.

4

I’ve now removed everything from the update loop, so all I am doing is printing out a string value from the list, and I have the above code, nothing else is running, and still the list items become null once I click on a button in the editor…

5

Can you share the entire script please? I suspect your problem lies elsewhere, not here.

6

Yeah, it has to!

I tried deleting the library folder twice, still no dice.

The entire script is massive, it wouldn’t help a whole lot.

However, all I am doing is this:

    public void aitest()
    {
        print("AITEST");
        for (int i = 0; i < persistentailist.Count; i++)
        {
            print(i + " " + persistentailist[i].player);
        }
    }

void Update()
    {
        aitest();

        if (manualsavetodb)
        {
            manualsavetodb = false;

            print("manual save to db:"); //player data only for now
            //saveavatarstatetodb();
            //saveaistatetodb();
        }
    }

I suspect the issue is with the custom class I am using in persistentailist. I am creating instances of this class and adding them to a list, and they appear in the unity editor as an object with no name, which seems to work fine, and used to, but maybe I need to create them in a different way?

    public List<persistentai> persistentailist = new List<persistentai>();

 persistentai aio = new persistentai(aname,aiobj.aiid, aiobj.assignment, false, aiobj.playerworldpos, aiobj.aiworldpos, aiobj.aicontrolobject);

public class persistentai : MonoBehaviour
{
    public string player;
    public int aiid;
    public string assignment;
    public bool aiactive;

    public List<serveraction> mainaiactiondb;

    //public persistentservertest pServer;
    public avataractionsavailable aaa;

    public serveraction currentaction;
    public float timeleft;

    public PW_Vector3D playerworldpos;
    public PW_Vector3D aiworldpos;
    public string aicontrolobject;

    public persistentai()
    {
        player = "";
        aiid = -1;
        assignment = "";
        aiactive = false;
        currentaction = new serveraction();
        timeleft = -1;
        mainaiactiondb = new List<serveraction>();

        playerworldpos = new PW_Vector3D(0, 0, 0);
        aiworldpos = new PW_Vector3D(0, 0, 0);
        aicontrolobject = "";
    }
7

I think I am making some progress here.

The issue only occurs with my custom class, not others, and I have just noticed in visual studio that under the “new” keyword there is this:

“UNT0010: Component “persistentAI” should not be instantiated directly”.

I suspect this is the issue.

8

You cannot instantiate a MonoBehaviour with ‘new’.

If you want a plain class with none of the Unity component stuff, simply don’t inherit from MonoBehaviour.

9

It looks like that might have been it!

But the weird thing is that this code was perfect for six months, it only started causing issues today. At least I’ll know for the future. Thanks a lot for your help!