Load Ocasionally Fails When Restarting Unity

[jspro]

Hello Toni,

I've run into a very frustrating bug; I'm not quite sure what the cause of it is.

Here is how I reproduce the bug,

1. I save the game while testing it.
2. As long as I don't restart Unity, loading the game works fine. (To be honest, I'm not 100% sure this is true, but it hasn't happened yet. )
3. I restart Unity, enter play mode, and load the game until the load fails. This usually takes between 1-10 restarts.

This is the saver data class where I first noticed the bug:

Code: Select all

    /// <summary>
    /// Saves the knowledge the player has learned.  
    /// </summary>
    public class InkStateManagerSaver : Saver
    {
        [Serializable]
        public class InkStateManagerData
        {
            public Character talkingTo;
            public List<Presentable> allKnown;
            public List<Presentable> allPresentableRepliesKeys;
            public List<Presentable> allPresentableRepliesValues;
        }

I eventually found that here, while applying the data, when the bug does occurs, the fields of data were null; talkingTo would be null, and the elements of the lists were all null as well:

Code: Select all

            if (string.IsNullOrEmpty(s)) return;
            var data = SaveSystem.Deserialize<InkStateManagerData>(s);
            if (data == null) return;

The save file seems to be fine; after all, the load doesn't always fail. And it's not just this class that's affected. I believe only fields are hold references are affected (although, again, not 100% sure. )

Have you seen anything like this before?

PS: Forgot to mention that I’m using the EasySave3 integration.

Best,
Malek

[Tony Li]

Hi,

What are Character and Presentable? Are they UnityObject types, such as ScriptableObjects or MonoBehaviours? If so, Unity's serializer can't serialize their references in a way that's consistent between runs. In general, only use basic types in your save data structures. For example, maintain a separate CharacterList:

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public class CharacterList : ScriptableObject
{
    public List<Character> characters;
}

and then store the character's name or index into CharacterList:

Code: Select all

[Serializable]
public class InkStateManagerData
{
    public int characterTalkingTo; // Index into CharacterList's characters list.
    ...

public override string RecordData()
{
    var data = new InkStateManagerData();
    data.characterTalkingTo = MyReferenceToCharacterList.characters.IndexOf(characterThatIAmTalkingTo);
    ...

public override void ApplyData(string s)
{
    var data = SaveSystem.Deserialize<InkStateManagerData>(s);
    characterThatIAmTalkingTo = (0 <= data.characterTalkingTo && data.characterTalkingTo < MyReferenceToCharacterList.Count)
        ? MyReferenceToCharacterList.characters[data.characterTalkingTo] : null;
    ...

Or you could switch to a different serialization method, such as making a custom DataSerializer class that uses Json.NET instead of the save system's JsonDataSerializer. (JsonDataSerializer uses Unity's very fast but limited JsonUtility.)

[jspro]

Right, I forgot to mention in my post that I’m using the EasySave3 integration, so the EasySave Serializer should be the one being used, and that asset can serialize Scriptable Objects.

[Tony Li]

If you're using ESSavedGameDataStorer, this just sends already-serialized data to ES3. Presumably the data has been serialized with JsonDataSerializer, which is the problem.

If that's the case, you can write a DataSerializer subclass that uses ES3's serialization instead. Make sure to remove JsonDataSerializer from your SaveSystem GameObject and add your custom ES3 DataSerializer in its place.

[jspro]

Ahh, that’s probably the culprit then. I’ll give it a shot and update you. Thanks Tony!

[Tony Li]

Glad to help!

[jspro]

Seems to be all good. Thanks again!