From e5d2e1653cef883d30f3dc6a4850fa72ee3ef713 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 20 Apr 2026 08:19:09 +0000
Subject: [PATCH 1/2] Initial plan


From 6dd15f074db96c9dbd2e3bb08cc92026fe82a15e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 20 Apr 2026 08:29:12 +0000
Subject: [PATCH 2/2] Guard static mesh merge grid against missing statics

Agent-Logs-Url: https://github.com/TombEngine/Tomb-Editor/sessions/8e9f590f-8231-4541-ab43-ad4af3742a46

Co-authored-by: Nickelony <20436882+Nickelony@users.noreply.github.com>
---
 TombLib/TombLib.Test/LevelSettingsTests.cs | 36 ++++++++++++++++++++++
 TombLib/TombLib/LevelData/LevelSettings.cs | 29 +++++++++++++++--
 2 files changed, 62 insertions(+), 3 deletions(-)
 create mode 100644 TombLib/TombLib.Test/LevelSettingsTests.cs

diff --git a/TombLib/TombLib.Test/LevelSettingsTests.cs b/TombLib/TombLib.Test/LevelSettingsTests.cs
new file mode 100644
index 000000000..c9420852e
--- /dev/null
+++ b/TombLib/TombLib.Test/LevelSettingsTests.cs
@@ -0,0 +1,36 @@
+using System.Linq;
+using System.Reflection;
+using TombLib.LevelData;
+using TombLib.Wad;
+
+namespace TombLib.Test;
+
+[TestClass]
+public class LevelSettingsTests
+{
+    [TestMethod]
+    public void AutoStaticMeshMergeEntry_StaticMesh_FallsBackToStaticIdNameWhenMissing()
+    {
+        var settings = new LevelSettings
+        {
+            GameVersion = TRVersion.Game.TR4
+        };
+
+        var entry = new AutoStaticMeshMergeEntry(123u, false, false, false, false, settings);
+
+        Assert.AreEqual(new WadStaticId(123u).ToString(settings.GameVersion), entry.StaticMesh);
+    }
+
+    [TestMethod]
+    public void Clone_ReparentsAutoStaticMeshMergeEntries()
+    {
+        var settings = new LevelSettings();
+        settings.AutoStaticMeshMerges.Add(new AutoStaticMeshMergeEntry(321u, true, false, false, false, settings));
+
+        var clonedSettings = settings.Clone();
+        var parentField = typeof(AutoStaticMeshMergeEntry).GetField("parent", BindingFlags.Instance | BindingFlags.NonPublic);
+
+        Assert.IsNotNull(parentField);
+        Assert.AreSame(clonedSettings, parentField.GetValue(clonedSettings.AutoStaticMeshMerges.Single()));
+    }
+}
diff --git a/TombLib/TombLib/LevelData/LevelSettings.cs b/TombLib/TombLib/LevelData/LevelSettings.cs
index 97fa8545f..fa6702809 100644
--- a/TombLib/TombLib/LevelData/LevelSettings.cs
+++ b/TombLib/TombLib/LevelData/LevelSettings.cs
@@ -35,7 +35,7 @@ public enum VariableType
 
     public class AutoStaticMeshMergeEntry : ICloneable, IEquatable<AutoStaticMeshMergeEntry>
     {
-        public string StaticMesh => parent.WadTryGetStatic(new WadStaticId(meshId)).ToString(parent.GameVersion);
+        public string StaticMesh => GetStaticMeshName();
 
         private readonly LevelSettings parent;
         public uint meshId;
@@ -53,9 +53,32 @@ public AutoStaticMeshMergeEntry(uint staticMesh, bool merge, bool interpretShade
             ClearShades = clearShades;
         }
 
+        private string GetStaticMeshName()
+        {
+            var staticMeshId = new WadStaticId(meshId);
+            var staticMesh = parent?.WadTryGetStatic(staticMeshId);
+
+            if (staticMesh == null)
+            {
+                if (parent == null)
+                {
+                    return staticMeshId.ToString();
+                }
+
+                return staticMeshId.ToString(parent.GameVersion);
+            }
+
+            return staticMesh.ToString(parent.GameVersion);
+        }
+
+        public AutoStaticMeshMergeEntry Clone(LevelSettings newParent)
+        {
+            return new AutoStaticMeshMergeEntry(meshId, Merge, InterpretShadesAsEffect, TintAsAmbient, ClearShades, newParent);
+        }
+
         public AutoStaticMeshMergeEntry Clone()
         {
-            return (AutoStaticMeshMergeEntry)MemberwiseClone();
+            return Clone(parent);
         }
 
         object ICloneable.Clone()
@@ -242,7 +265,7 @@ public LevelSettings Clone()
             result.Textures = Textures.ConvertAll(texture => (LevelTexture)texture.Clone());
             result.AnimatedTextureSets = AnimatedTextureSets.ConvertAll(set => set.Clone());
             result.ImportedGeometries = ImportedGeometries.ConvertAll(geometry => geometry.Clone());
-            result.AutoStaticMeshMerges = AutoStaticMeshMerges.ConvertAll(entry => entry.Clone());
+            result.AutoStaticMeshMerges = AutoStaticMeshMerges.ConvertAll(entry => entry.Clone(result));
             return result;
         }