From cdca5b4a2896fbc3cd4150da2d5afa0406de1c44 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Sun, 8 Aug 2021 18:38:26 +0200
Subject: [PATCH] Fix undo for missing actor children and scripts when doing
 Convert action

---
 Source/Editor/Modules/SceneEditingModule.cs   | 44 ++++++++-----------
 Source/Editor/SceneGraph/SceneGraphTools.cs   | 28 ++++++++++++
 .../Editor/Undo/Actions/DeleteActorsAction.cs |  1 +
 3 files changed, 48 insertions(+), 25 deletions(-)

diff --git a/Source/Editor/Modules/SceneEditingModule.cs b/Source/Editor/Modules/SceneEditingModule.cs
index 021817945..a3f23f775 100644
--- a/Source/Editor/Modules/SceneEditingModule.cs
+++ b/Source/Editor/Modules/SceneEditingModule.cs
@@ -303,26 +303,28 @@ namespace FlaxEditor.Modules
         {
             if (!Editor.SceneEditing.HasSthSelected || !(Editor.SceneEditing.Selection[0] is ActorNode))
                 return;
-
             if (Level.IsAnySceneLoaded == false)
                 throw new InvalidOperationException("Cannot spawn actor when no scene is loaded.");
 
             var actionList = new IUndoAction[4];
-            Actor old = ((ActorNode)Editor.SceneEditing.Selection[0]).Actor;
-            Actor actor = (Actor)FlaxEngine.Object.New(to);
+            var oldNode = (ActorNode)Editor.SceneEditing.Selection[0];
+            var old = oldNode.Actor;
+            var actor = (Actor)FlaxEngine.Object.New(to);
             var parent = old.Parent;
             var orderInParent = old.OrderInParent;
 
+            // Steps:
+            // - deselect old actor
+            // - destroy old actor
+            // - spawn new actor
+            // - select new actor
+
             SelectionDeleteBegin?.Invoke();
 
             actionList[0] = new SelectionChangeAction(Selection.ToArray(), new SceneGraphNode[0], OnSelectionUndo);
             actionList[0].Do();
 
-            actionList[1] = new DeleteActorsAction(new List<SceneGraphNode>
-            {
-                Editor.Instance.Scene.GetActorNode(old)
-            });
-            actionList[1].Do();
+            actionList[1] = new DeleteActorsAction(oldNode.BuildAllNodes().Where(x => x.CanDelete).ToList());
 
             SelectionDeleteEnd?.Invoke();
 
@@ -345,17 +347,12 @@ namespace FlaxEditor.Modules
                 actor.StaticFlags = StaticFlags.None;
 
             // Move children
-            for (var i = old.ScriptsCount - 1; i >= 0; i--)
-            {
-                var script = old.Scripts[i];
-                script.Actor = actor;
-                Guid newid = Guid.NewGuid();
-                FlaxEngine.Object.Internal_ChangeID(FlaxEngine.Object.GetUnmanagedPtr(script), ref newid);
-            }
-            for (var i = old.Children.Length - 1; i >= 0; i--)
-            {
-                old.Children[i].Parent = actor;
-            }
+            var scripts = old.Scripts;
+            for (var i = scripts.Length - 1; i >= 0; i--)
+                scripts[i].Actor = actor;
+            var children = old.Children;
+            for (var i = children.Length - 1; i >= 0; i--)
+                children[i].Parent = actor;
 
             var actorNode = Editor.Instance.Scene.GetActorNode(actor);
             if (actorNode == null)
@@ -364,16 +361,13 @@ namespace FlaxEditor.Modules
             actorNode.PostSpawn();
             Editor.Scene.MarkSceneEdited(actor.Scene);
 
-            actionList[2] = new DeleteActorsAction(new List<SceneGraphNode>
-            {
-                actorNode
-            }, true);
+            actionList[1].Do();
+            actionList[2] = new DeleteActorsAction(actorNode.BuildAllNodes().Where(x => x.CanDelete).ToList(), true);
 
             actionList[3] = new SelectionChangeAction(new SceneGraphNode[0], new SceneGraphNode[] { actorNode }, OnSelectionUndo);
             actionList[3].Do();
 
-            var actions = new MultiUndoAction(actionList);
-            Undo.AddAction(actions);
+            Undo.AddAction(new MultiUndoAction(actionList, "Convert actor"));
 
             SpawnEnd?.Invoke();
 
diff --git a/Source/Editor/SceneGraph/SceneGraphTools.cs b/Source/Editor/SceneGraph/SceneGraphTools.cs
index b20303a14..1416e379b 100644
--- a/Source/Editor/SceneGraph/SceneGraphTools.cs
+++ b/Source/Editor/SceneGraph/SceneGraphTools.cs
@@ -125,5 +125,33 @@ namespace FlaxEditor.SceneGraph
                 FillTree(target, result);
             }
         }
+
+        /// <summary>
+        /// Builds the list made of all nodes in the input scene tree root and child tree. The result collection contains all nodes in the tree.
+        /// </summary>
+        /// <param name="node">The node.</param>
+        /// <returns>The result.</returns>
+        public static List<SceneGraphNode> BuildAllNodes<T>(this T node)
+        where T : SceneGraphNode
+        {
+            var list = new List<SceneGraphNode>();
+            BuildAllNodes(node, list);
+            return list;
+        }
+
+        /// <summary>
+        /// Builds the list made of all nodes in the input scene tree root and child tree. The result collection contains all nodes in the tree.
+        /// </summary>
+        /// <param name="node">The node.</param>
+        /// <param name="result">The result.</param>
+        public static void BuildAllNodes<T>(this T node, List<SceneGraphNode> result)
+        where T : SceneGraphNode
+        {
+            if (node == null || result == null)
+                throw new ArgumentNullException();
+            result.Clear();
+            result.Add(node);
+            FillTree(node, result);
+        }
     }
 }
diff --git a/Source/Editor/Undo/Actions/DeleteActorsAction.cs b/Source/Editor/Undo/Actions/DeleteActorsAction.cs
index 41dac3ccc..3dc7b77cf 100644
--- a/Source/Editor/Undo/Actions/DeleteActorsAction.cs
+++ b/Source/Editor/Undo/Actions/DeleteActorsAction.cs
@@ -135,6 +135,7 @@ namespace FlaxEditor.Actions
                 node.Delete();
             }
             _nodeParents.Clear();
+            FlaxEngine.Scripting.FlushRemovedObjects();
         }
 
         /// <summary>