From 14506a4282b6b9079280ec54f50f46ba041c0d10 Mon Sep 17 00:00:00 2001
From: David Snopek <dsnopek@gmail.com>
Date: Fri, 10 May 2024 12:07:21 -0500
Subject: [PATCH] GDExtension: Prevent crash during shutdown as singletons are
 deleted

---
 core/config/engine.cpp                 |  6 ++++++
 core/config/engine.h                   |  2 +-
 core/extension/gdextension_manager.cpp |  3 +++
 core/object/object.cpp                 | 10 +++++++---
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/core/config/engine.cpp b/core/config/engine.cpp
index f2f8aebe8b5..3574430cf75 100644
--- a/core/config/engine.cpp
+++ b/core/config/engine.cpp
@@ -384,6 +384,12 @@ Engine::Engine() {
 	singleton = this;
 }
 
+Engine::~Engine() {
+	if (singleton == this) {
+		singleton = nullptr;
+	}
+}
+
 Engine::Singleton::Singleton(const StringName &p_name, Object *p_ptr, const StringName &p_class_name) :
 		name(p_name),
 		ptr(p_ptr),
diff --git a/core/config/engine.h b/core/config/engine.h
index 8dece803e33..7e617d8773a 100644
--- a/core/config/engine.h
+++ b/core/config/engine.h
@@ -187,7 +187,7 @@ public:
 	bool notify_frame_server_synced();
 
 	Engine();
-	virtual ~Engine() {}
+	virtual ~Engine();
 };
 
 #endif // ENGINE_H
diff --git a/core/extension/gdextension_manager.cpp b/core/extension/gdextension_manager.cpp
index a4d032f22f7..1ee9de07768 100644
--- a/core/extension/gdextension_manager.cpp
+++ b/core/extension/gdextension_manager.cpp
@@ -295,6 +295,9 @@ GDExtensionManager::GDExtensionManager() {
 }
 
 GDExtensionManager::~GDExtensionManager() {
+	if (singleton == this) {
+		singleton = nullptr;
+	}
 #ifndef DISABLE_DEPRECATED
 	GDExtensionCompatHashes::finalize();
 #endif
diff --git a/core/object/object.cpp b/core/object/object.cpp
index dfc8e2a29aa..5125ab8a6ec 100644
--- a/core/object/object.cpp
+++ b/core/object/object.cpp
@@ -2095,9 +2095,13 @@ Object::~Object() {
 		_extension_instance = nullptr;
 	}
 #ifdef TOOLS_ENABLED
-	else if (_instance_bindings != nullptr && Engine::get_singleton()->is_extension_reloading_enabled()) {
-		for (uint32_t i = 0; i < _instance_binding_count; i++) {
-			GDExtensionManager::get_singleton()->untrack_instance_binding(_instance_bindings[i].token, this);
+	else if (_instance_bindings != nullptr) {
+		Engine *engine = Engine::get_singleton();
+		GDExtensionManager *gdextension_manager = GDExtensionManager::get_singleton();
+		if (engine && gdextension_manager && engine->is_extension_reloading_enabled()) {
+			for (uint32_t i = 0; i < _instance_binding_count; i++) {
+				gdextension_manager->untrack_instance_binding(_instance_bindings[i].token, this);
+			}
 		}
 	}
 #endif