From 20be441026ce3e294bef110279233a8168d219c9 Mon Sep 17 00:00:00 2001
From: Kehom <kehom@hotmail.com>
Date: Thu, 16 Feb 2023 11:43:26 -0300
Subject: [PATCH] Unregister custom classes in reverse registration order

---
 include/godot_cpp/core/class_db.hpp | 3 +++
 src/core/class_db.cpp               | 9 ++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/godot_cpp/core/class_db.hpp b/include/godot_cpp/core/class_db.hpp
index 425d5a21..b1625bf2 100644
--- a/include/godot_cpp/core/class_db.hpp
+++ b/include/godot_cpp/core/class_db.hpp
@@ -105,6 +105,8 @@ private:
 	// This may only contain custom classes, not Godot classes
 	static std::unordered_map<StringName, ClassInfo> classes;
 	static std::unordered_map<StringName, const GDExtensionInstanceBindingCallbacks *> instance_binding_callbacks;
+	// Used to remember the custom class registration order.
+	static std::vector<StringName> class_register_order;
 
 	static MethodBind *bind_methodfi(uint32_t p_flags, MethodBind *p_bind, const MethodDefinition &method_name, const void **p_defs, int p_defcount);
 	static void initialize_class(const ClassInfo &cl);
@@ -178,6 +180,7 @@ void ClassDB::_register_class(bool p_virtual) {
 		cl.parent_ptr = &parent_it->second;
 	}
 	classes[cl.name] = cl;
+	class_register_order.push_back(cl.name);
 
 	// Register this class with Godot
 	GDExtensionClassCreationInfo class_info = {
diff --git a/src/core/class_db.cpp b/src/core/class_db.cpp
index 551cb890..e8bb40c6 100644
--- a/src/core/class_db.cpp
+++ b/src/core/class_db.cpp
@@ -41,6 +41,7 @@ namespace godot {
 
 std::unordered_map<StringName, ClassDB::ClassInfo> ClassDB::classes;
 std::unordered_map<StringName, const GDExtensionInstanceBindingCallbacks *> ClassDB::instance_binding_callbacks;
+std::vector<StringName> ClassDB::class_register_order;
 GDExtensionInitializationLevel ClassDB::current_level = GDEXTENSION_INITIALIZATION_CORE;
 
 MethodDefinition D_METHOD(StringName p_name) {
@@ -348,13 +349,15 @@ void ClassDB::initialize(GDExtensionInitializationLevel p_level) {
 }
 
 void ClassDB::deinitialize(GDExtensionInitializationLevel p_level) {
-	for (const std::pair<StringName, ClassInfo> pair : classes) {
-		const ClassInfo &cl = pair.second;
+	for (std::vector<StringName>::reverse_iterator i = class_register_order.rbegin(); i != class_register_order.rend(); ++i) {
+		const StringName &name = *i;
+		const ClassInfo &cl = classes[name];
+
 		if (cl.level != p_level) {
 			continue;
 		}
 
-		internal::gdextension_interface_classdb_unregister_extension_class(internal::library, cl.name._native_ptr());
+		internal::gdextension_interface_classdb_unregister_extension_class(internal::library, name._native_ptr());
 
 		for (auto method : cl.method_map) {
 			memdelete(method.second);