From f0959761e8d3a293197d26b36700643d6490d228 Mon Sep 17 00:00:00 2001
From: in0finite <leshow816@gmail.com>
Date: Sat, 22 Jan 2022 01:24:52 +0100
Subject: [PATCH] add more error-proof checking for startup singletons

---
 Assets/Scripts/Utilities/SingletonComponent.cs |  6 ++++++
 Assets/Scripts/Utilities/StartupSingleton.cs   | 11 ++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Assets/Scripts/Utilities/SingletonComponent.cs b/Assets/Scripts/Utilities/SingletonComponent.cs
index 1153c8aa..ace8b06c 100644
--- a/Assets/Scripts/Utilities/SingletonComponent.cs
+++ b/Assets/Scripts/Utilities/SingletonComponent.cs
@@ -47,6 +47,8 @@ namespace SanAndreasUnity.Utilities
                 throw new Exception($"Awake() method called twice for singleton of type {this.GetType().Name}");
             }
 
+            this.OnSingletonAwakeValidate();
+
             Singleton = (T)this;
 
             this.OnSingletonAwake();
@@ -56,6 +58,10 @@ namespace SanAndreasUnity.Utilities
         {
         }
 
+        protected virtual void OnSingletonAwakeValidate()
+        {
+        }
+
         private void OnDisable()
         {
             if (Singleton != this)
diff --git a/Assets/Scripts/Utilities/StartupSingleton.cs b/Assets/Scripts/Utilities/StartupSingleton.cs
index 0bd55780..f8369f4c 100644
--- a/Assets/Scripts/Utilities/StartupSingleton.cs
+++ b/Assets/Scripts/Utilities/StartupSingleton.cs
@@ -1,7 +1,16 @@
-namespace SanAndreasUnity.Utilities
+using UnityEngine.SceneManagement;
+
+namespace SanAndreasUnity.Utilities
 {
     public class StartupSingleton<T> : SingletonComponent<T>
         where T : StartupSingleton<T>
     {
+        protected override void OnSingletonAwakeValidate()
+        {
+            Scene activeScene = SceneManager.GetActiveScene();
+
+            if (!activeScene.IsValid() || activeScene.buildIndex != 0)
+                throw new System.Exception("Startup singleton can only be initialized in startup scene");
+        }
     }
 }