Example of how to use ObjectChangeEvents in Unity

ObjectChangeEventsExample.cs

using System.Text;
using UnityEditor;
using UnityEngine;

[InitializeOnLoad]
public class ObjectChangeEventsExample
{
    static ObjectChangeEventsExample()    
    {
        ObjectChangeEvents.changesPublished += ChangesPublished;
    }

    static void ChangesPublished(ref ObjectChangeEventStream stream)
    {
        for (int i = 0; i < stream.length; ++i)
        {
            var type = stream.GetEventType(i);
            switch (type)
            {
                case ObjectChangeKind.ChangeScene:
                    stream.GetChangeSceneEvent(i, out var changeSceneEvent);
                    Debug.Log($"{type}: {changeSceneEvent.scene}");
                    break;

                case ObjectChangeKind.CreateGameObjectHierarchy:
                    stream.GetCreateGameObjectHierarchyEvent(i, out var createGameObjectHierarchyEvent);
                    var newGameObject = EditorUtility.InstanceIDToObject(createGameObjectHierarchyEvent.instanceId) as GameObject;
                    Debug.Log($"{type}: {newGameObject} in scene {createGameObjectHierarchyEvent.scene}.");
                    break;

                case ObjectChangeKind.ChangeGameObjectStructureHierarchy:
                    stream.GetChangeGameObjectStructureHierarchyEvent(i, out var changeGameObjectStructureHierarchy);
                    var gameObject = EditorUtility.InstanceIDToObject(changeGameObjectStructureHierarchy.instanceId) as GameObject;
                    Debug.Log($"{type}: {gameObject} in scene {changeGameObjectStructureHierarchy.scene}.");
                    break;

                case ObjectChangeKind.ChangeGameObjectStructure:
                    stream.GetChangeGameObjectStructureEvent(i, out var changeGameObjectStructure);
                    var gameObjectStructure = EditorUtility.InstanceIDToObject(changeGameObjectStructure.instanceId) as GameObject;
                    Debug.Log($"{type}: {gameObjectStructure} in scene {changeGameObjectStructure.scene}.");
                    break;

                case ObjectChangeKind.ChangeGameObjectParent:
                    stream.GetChangeGameObjectParentEvent(i, out var changeGameObjectParent);
                    var gameObjectChanged = EditorUtility.InstanceIDToObject(changeGameObjectParent.instanceId) as GameObject;
                    var newParentGo = EditorUtility.InstanceIDToObject(changeGameObjectParent.newParentInstanceId) as GameObject;
                    var previousParentGo = EditorUtility.InstanceIDToObject(changeGameObjectParent.previousParentInstanceId) as GameObject;
                    Debug.Log($"{type}: {gameObjectChanged} from {previousParentGo} to {newParentGo} from scene {changeGameObjectParent.previousScene} to scene {changeGameObjectParent.newScene}.");
                    break;

                case ObjectChangeKind.ChangeGameObjectOrComponentProperties:
                    stream.GetChangeGameObjectOrComponentPropertiesEvent(i, out var changeGameObjectOrComponent);
                    var goOrComponent = EditorUtility.InstanceIDToObject(changeGameObjectOrComponent.instanceId);
                    if (goOrComponent is GameObject go)
                    {
                        Debug.Log($"{type}: GameObject {go} change properties in scene {changeGameObjectOrComponent.scene}.");
                    }
                    else if (goOrComponent is Component component)
                    {
                        Debug.Log($"{type}: Component {component} change properties in scene {changeGameObjectOrComponent.scene}.");
                    }
                    break;

                case ObjectChangeKind.DestroyGameObjectHierarchy:
                    stream.GetDestroyGameObjectHierarchyEvent(i, out var destroyGameObjectHierarchyEvent);
                    // The destroyed GameObject can not be converted with EditorUtility.InstanceIDToObject as it has already been destroyed.
                    var destroyParentGo = EditorUtility.InstanceIDToObject(destroyGameObjectHierarchyEvent.parentInstanceId) as GameObject;
                    Debug.Log($"{type}: {destroyGameObjectHierarchyEvent.instanceId} with parent {destroyParentGo} in scene {destroyGameObjectHierarchyEvent.scene}.");
                    break;

                case ObjectChangeKind.CreateAssetObject:
                    stream.GetCreateAssetObjectEvent(i, out var createAssetObjectEvent);
                    var createdAsset = EditorUtility.InstanceIDToObject(createAssetObjectEvent.instanceId);
                    var createdAssetPath = AssetDatabase.GUIDToAssetPath(createAssetObjectEvent.guid);
                    Debug.Log($"{type}: {createdAsset} at {createdAssetPath} in scene {createAssetObjectEvent.scene}.");
                    break;

                case ObjectChangeKind.DestroyAssetObject:
                    stream.GetDestroyAssetObjectEvent(i, out var destroyAssetObjectEvent);
                    // The destroyed asset can not be converted with EditorUtility.InstanceIDToObject as it has already been destroyed.
                    Debug.Log($"{type}: Instance Id {destroyAssetObjectEvent.instanceId} with Guid {destroyAssetObjectEvent.guid} in scene {destroyAssetObjectEvent.scene}.");
                    break;

                case ObjectChangeKind.ChangeAssetObjectProperties:
                    stream.GetChangeAssetObjectPropertiesEvent(i, out var changeAssetObjectPropertiesEvent);
                    var changeAsset = EditorUtility.InstanceIDToObject(changeAssetObjectPropertiesEvent.instanceId);
                    var changeAssetPath = AssetDatabase.GUIDToAssetPath(changeAssetObjectPropertiesEvent.guid);
                    Debug.Log($"{type}: {changeAsset} at {changeAssetPath} in scene {changeAssetObjectPropertiesEvent.scene}.");
                    break;

                case ObjectChangeKind.UpdatePrefabInstances:
                    stream.GetUpdatePrefabInstancesEvent(i, out var updatePrefabInstancesEvent);
                    string s = "";
                    s += $"{type}: scene {updatePrefabInstancesEvent.scene}. Instances ({updatePrefabInstancesEvent.instanceIds.Length}):\n";
                    foreach (var prefabId in updatePrefabInstancesEvent.instanceIds)
                    {
                        s += EditorUtility.InstanceIDToObject(prefabId).ToString() + "\n";
                    }
                    Debug.Log(s);
                    break;
            }
        }
    }
}

This is so useful, thanks! Please add this to de docs!!!

I did add It to the docs docs.unity3d.com/2023.1/Documentation/ScriptReference/ObjectChangeEvents-changesPublished.html

Is this compatible with 2022 LTS ? (So it could be added to the doc as well)

Is this compatible with 2022 LTS ? (So it could be added to the doc as well)

No, some of the API in the example are missing in 2022 LTS. Such as EditorUtility.InstanceIDToObject

Is this compatible with 2022 LTS ? (So it could be added to the doc as well)

No, some of the API in the example are missing in 2022 LTS. Such as EditorUtility.InstanceIDToObject

???
https://docs.unity3d.com/2022.3/Documentation/ScriptReference/EditorUtility.InstanceIDToObject.html

Is this compatible with 2022 LTS ? (So it could be added to the doc as well)

No, some of the API in the example are missing in 2022 LTS. Such as EditorUtility.InstanceIDToObject

??? https://docs.unity3d.com/2022.3/Documentation/ScriptReference/EditorUtility.InstanceIDToObject.html

Looks like it has been backported to 2022 LTS