Implement PropertyModifier using Preset instead of hacky PropertyVariant

Editor Presets draw perfect inspectors without the need for hacky reflections

Author: gilzoide

Editor/CustomInspectors/AImportTimeObjectModifierEditor.cs

@@ -1,5 +1,4 @@
-#if !UNITY_2020_2_OR_NEWER
-using UnityEditor;
+using UnityEditor;
 
 namespace Gilzoide.ConditionalObjects.Editor
 {
@@ -8,13 +7,14 @@ public class AImportTimeObjectModifierEditor : UnityEditor.Editor
     {
         public override void OnInspectorGUI()
         {
+#if !UNITY_2020_2_OR_NEWER
             if (target.IsPartOfPrefab())
             {
                 EditorGUILayout.HelpBox($"{target.GetType().Name} in Prefab will only work when prefab is instanced in scenes. Use Unity 2020.2+ for full prefab support.", MessageType.Warning);
             }
+#endif
 
             DrawDefaultInspector();
         }
     }
-}
-#endif
+}

Editor/CustomInspectors/CustomPropertyDrawerFinder.cs

@@ -0,0 +1,58 @@
+using UnityEditor;
+using UnityEditor.Presets;
+using UnityEngine;
+
+namespace Gilzoide.ConditionalObjects.Editor
+{
+    [CustomEditor(typeof(PropertyModifier))]
+    public class PropertyModifierEditor : AImportTimeObjectModifierEditor
+    {
+        private SerializedProperty _gameObjectProperty;
+        private SerializedProperty _componentIndexProperty;
+        private GlobalObjectId _serializedObjectId;
+        private Preset _preset;
+        private UnityEditor.Editor _presetEditor;
+
+        void OnEnable()
+        {
+            _gameObjectProperty = serializedObject.FindProperty($"{nameof(PropertyModifier.Target)}.{nameof(GameObjectOrComponent.GameObject)}");
+            _componentIndexProperty = serializedObject.FindProperty($"{nameof(PropertyModifier.Target)}.{nameof(GameObjectOrComponent.ComponentIndex)}");
+            _serializedObjectId = GlobalObjectId.GetGlobalObjectIdSlow(target);
+            _preset = EmbeddedPresetHolder.Instance.GetOrCreatePreset(_serializedObjectId, GetTarget());
+        }
+
+        void OnDisable()
+        {
+            _gameObjectProperty.Dispose();
+            _componentIndexProperty.Dispose();
+            DestroyImmediate(_presetEditor);
+        }
+
+        public override void OnInspectorGUI()
+        {
+            Object previousTarget = GetTarget();
+            DrawDefaultInspector();
+            Object newTarget = GetTarget();
+            if (newTarget != previousTarget)
+            {
+                Undo.RecordObject(EmbeddedPresetHolder.Instance, "");
+                _preset = EmbeddedPresetHolder.Instance.GetOrCreatePreset(_serializedObjectId, newTarget);
+            }
+
+            if (_preset != null)
+            {
+                if (_presetEditor == null || _presetEditor.target != _preset)
+                {
+                    DestroyImmediate(_presetEditor);
+                    _presetEditor = CreateEditor(_preset);
+                }
+                _presetEditor.OnInspectorGUI();
+            }
+        }
+
+        private Object GetTarget()
+        {
+            return ((GameObject) _gameObjectProperty.objectReferenceValue).ComponentAtIndexOrSelf(_componentIndexProperty.intValue);
+        }
+    }
+}