Bug (?) with Save Game (on separate thread only) when syncing a GameObject GVar

Phantasie

Hi

I believe this is a bug. I haven't attempted to reproduce outside my project.

1. Ensure AC Game Editor -> Settings -> Saving -> "Save using separate thread?" is checked (enabled)
2. Have a variable linking script that syncs a GameObject to a global variable (who's type is Game Object as well). (This script is on the player prefab. I dont think this is being a prefab is relevant)
3. OnDownload should sync the GameObject variable.

Given the above, when you save Unity with throw a "UnityException: GetName can only be called from the main thread."

It looks like the GVar GameObjectValue set property access the .name member, which in turn calls Unity.GetName - which isnt thread safe. Maybe you need to cache the name, IDK.

Disabling saving on a separate thread prevents this bug from occurring. This is fine for me.

Call stack

OnDownload() is simple. Both parameters have the expected values.

private void OnDownload(GVar variable, Variables variables)
{
    if (variable.id == variableIDToSyncWith)
    {               
        variable.GameObjectValue = characterGameObject;
    }
}

Note: I also dont even need to serialize/ save this game object global variable, since its just a way for action lists to have access to a game object that code controls. If I missed documentation stating you need to explicitly avoid syncing a game object variable during save, then sorry

ChrisIceBox

Thanks for the report. Yes, it's an issue with GameObjectValue being set - Unity doesn't allow access on a separate thread.

If the Variable doesn't need saving, you can hook into the OnBeforeSaving event to inform your script to avoid the call within OnDownload while saving, i.e.:

bool isSaving;

void OnEnable()
{
    EventManager.OnBeforeSaving += OnBeforeSaving;
    EventManager.OnFinishSaving += OnFinishSaving;
    EventManager.OnFailSaving += OnFailSaving;
}

void OnDisable()
{
    EventManager.OnBeforeSaving -= OnBeforeSaving;
    EventManager.OnFinishSaving -= OnFinishSaving;
    EventManager.OnFailSaving -= OnFailSaving;
}

void OnBeforeSaving (int saveID) => isSaving = true;
void OnFinishSaving (SaveFile saveFile) => isSaving = false;
void OnFailSaving (int saveID) => isSaving = false;

private void OnDownload(GVar variable, Variables variables)
{
    if (isSaving) return;
    //
}