From 3623aa6d71d76cc5dcaf07f4f72e69c64921cc89 Mon Sep 17 00:00:00 2001
From: Team <timonsol13@gmail.com>
Date: Wed, 24 Nov 2021 01:02:01 +0200
Subject: [PATCH] Fix destroying assets error

Destroying assets is not permitted to avoid data loss.
If you really want to remove an asset use DestroyImmediate (theObject, true);
UnityEngine.Object:Destroy (UnityEngine.Object)
XNode.NodeGraph:Clear () (at Assets/Scripts/xNode-1.8.0/Scripts/NodeGraph.cs:51)
XNode.NodeGraph:OnDestroy () (at Assets/Scripts/xNode-1.8.0/Scripts/NodeGraph.cs:83)

This can be caused by destroying instantiated NodeGraph.
Fixed by instantiating nodes in Awake.
---
 Scripts/NodeGraph.cs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/Scripts/NodeGraph.cs b/Scripts/NodeGraph.cs
index d928f94..ef0a314 100644
--- a/Scripts/NodeGraph.cs
+++ b/Scripts/NodeGraph.cs
@@ -10,6 +10,15 @@ namespace XNode {
         /// <summary> All nodes in the graph. <para/>
         /// See: <see cref="AddNode{T}"/> </summary>
         [SerializeField] public List<Node> nodes = new List<Node>();
+        
+        private void Awake() {
+            List<Node> newNodes = new List<Node>(nodes.Count);
+			foreach (var node in nodes) {
+                newNodes.Add(Instantiate(node));
+			}
+            nodes.Clear();
+            nodes = newNodes;
+        }
 
         /// <summary> Add a node to the graph by type (convenience method - will call the System.Type version) </summary>
         public T AddNode<T>() where T : Node {
@@ -47,7 +56,8 @@ namespace XNode {
         public virtual void Clear() {
             if (Application.isPlaying) {
                 for (int i = 0; i < nodes.Count; i++) {
-                    Destroy(nodes[i]);
+                    if(nodes[i])     //Graph destroy nodes only here, but this check prevent nullref when node was destroyed outside
+                        Destroy(nodes[i]);
                 }
             }
             nodes.Clear();
@@ -121,4 +131,4 @@ namespace XNode {
         }
 #endregion
     }
-}
\ No newline at end of file
+}