Remove empty object events to prevent segfault

UndertaleModLib/Models/UndertaleGameObject.cs

@@ -209,6 +209,7 @@ public void Serialize(UndertaleWriter writer)
         {
             v.Serialize(writer);
         }
+        FixEvents();
         writer.WriteUndertaleObject(Events);
     }
 
@@ -259,6 +260,24 @@ public void Unserialize(UndertaleReader reader)
         Events = reader.ReadUndertaleObject<UndertalePointerList<UndertalePointerList<Event>>>();
     }
 
+    /// <summary>
+    /// It is possible to create a new event in the UndertaleModTool GUI that has no actions.
+    /// Events with zero actions will lead to a segfault in the runner when loading chunk OBJT,
+    /// because it assumes there is at least one action per event.
+    /// This has been proven on Undertale 1.01, maybe modern runners are not affected.
+    ///
+    /// This method removes these empty events.
+    /// </summary>
+    private void FixEvents() {
+        foreach (UndertalePointerList<Event> events in Events) {
+            for (int i = events.Count - 1; i >= 0; i--) {
+                if (events[i].Actions.Count == 0) {
+                    events.RemoveAt(i);
+                }
+            }
+        }
+    }
+
     /// <inheritdoc cref="UndertaleObject.UnserializeChildObjectCount(UndertaleReader)"/>
     public static uint UnserializeChildObjectCount(UndertaleReader reader)
     {
@@ -1717,4 +1736,4 @@ public enum EventSubtypeGesture : uint
     /// The global rotate end event.
     /// </summary>
     GlobalRotateEnd = 76,
-}
+}