DynamicObstacle from a prefab causes changes in Scene

[onimitch]

• A* version: 5.3.3
• Unity version: 6.0.36f1

I often get lots of scene changes like this, when I have a Dynamic Obstacle in a Prefab.

Investigating I have a feeling that it might be down to the prev and next fields from GraphModifier, because they can point to objects from outside the prefabs? But I’m not 100% sure. In the Prefab overrides, Unity doesn’t show any changes to the object, so it’s clearly in one of the fields that aren’t public to the inspector.

It’s becoming a bit of a pain as on our project we need to tightly control changes to prefabs, and often make sure we apply prefab changes down our tree (i.e we have a few levels of nested prefabs and make sure changes get applied down to the lowest level). These scene changes cause a bit of friction which would be nice to not have.

I don’t know whether this is something that could be changed or if there is a potential workaround we could deploy. Happy to hear of suggestions.

[aron_granberg]

Hi

Can you diff the actual scene or .prefab files to see what’s causing the change?

[onimitch]

Ah, sorry I didn’t think of that myself! From the diff, it looks like its the uniqueID field.

For full context, I edit a prefab in the scene by clicking into the prefab, aka in prefab edit mode, adding a Dynamic obstacle to a GameObject in there, savijng and then going back to the scene. I could see in the Unity Hierarchy that the Prefab in the scene was highlighted blue to show changes.

The scene itself didn’t immediately show it needed saving (i.e it wasn’t marked with a *), but if I forced a save by making an unrelated change & reversing so I could then save the file, below is a diff of the Scene file.

As some extra confirmation from Unity itself, if I go back into the prefab and remove that Dynamic Obstacle, back in the scene I then see this under Unused Overrides.