Apply singleton instance binding clean-up fix no matter how it is created

Author: dsnopek

binding_generator.py

@@ -2078,6 +2078,7 @@ def generate_engine_class_source(class_api, used_classes, fully_used_classes, us
     result = []
 
     class_name = class_api["name"]
+    inherits = class_api["inherits"] if "inherits" in class_api else "Wrapped"
     snake_class_name = camel_to_snake(class_name)
     is_singleton = class_name in singletons
 
@@ -2117,27 +2118,37 @@ def generate_engine_class_source(class_api, used_classes, fully_used_classes, us
         result.append("#ifdef DEBUG_ENABLED")
         result.append("\t\tERR_FAIL_NULL_V(singleton_obj, nullptr);")
         result.append("#endif // DEBUG_ENABLED")
+        # This will lead to the constructor which will set `singleton`.
         result.append(
-            f"\t\tsingleton = reinterpret_cast<{class_name} *>(::godot::gdextension_interface::object_get_instance_binding(singleton_obj, ::godot::gdextension_interface::token, &{class_name}::_gde_binding_callbacks));"
+            f"\t\t::godot::gdextension_interface::object_get_instance_binding(singleton_obj, ::godot::gdextension_interface::token, &{class_name}::_gde_binding_callbacks);"
         )
         result.append("#ifdef DEBUG_ENABLED")
         result.append("\t\tERR_FAIL_NULL_V(singleton, nullptr);")
         result.append("#endif // DEBUG_ENABLED")
-        result.append("\t\tif (likely(singleton)) {")
-        result.append(f"\t\t\tClassDB::_register_engine_singleton({class_name}::get_class_static(), singleton);")
-        result.append("\t\t}")
         result.append("\t}")
         result.append("\treturn singleton;")
         result.append("}")
         result.append("")
 
+        result.append(f"{class_name}::{class_name}(GodotObject *p_godot_object) : {inherits}(p_godot_object) {{")
+        result.append("\tif (singleton == nullptr) {")
+        result.append("\t\tsingleton = this;")
+        result.append(f"\t\tClassDB::_register_engine_singleton({class_name}::get_class_static(), singleton);")
+        result.append("\t}")
+        result.append("}")
+        result.append("")
+
         result.append(f"{class_name}::~{class_name}() {{")
         result.append("\tif (singleton == this) {")
         result.append(f"\t\tClassDB::_unregister_engine_singleton({class_name}::get_class_static());")
         result.append("\t\tsingleton = nullptr;")
         result.append("\t}")
         result.append("}")
         result.append("")
+    else:
+        result.append(f"{class_name}::{class_name}(GodotObject *p_godot_object) : {inherits}(p_godot_object) {{")
+        result.append("}")
+        result.append("")
 
     if "methods" in class_api:
         for method in class_api["methods"]:

include/godot_cpp/classes/wrapped.hpp

@@ -434,7 +434,7 @@ private: \
 \
 protected: \
 	m_class(const char *p_godot_class) : m_inherits(p_godot_class) {} \
-	m_class(GodotObject *p_godot_object) : m_inherits(p_godot_object) {} \
+	m_class(GodotObject *p_godot_object); \
 \
 	static void _bind_methods() {} \
 \

test/build_profile.json

@@ -11,6 +11,7 @@
 		"TileMap",
 		"TileSet",
 		"Tween",
-		"Viewport"
+		"Viewport",
+		"XRServer"
 	]
 }

test/project/main.gd

@@ -276,8 +276,9 @@ func _ready():
 	assert_equal(example.test_virtual_implemented_in_script("Virtual", 939), "Implemented")
 	assert_equal(custom_signal_emitted, ["Virtual", 939])
 
-	# Test that we can access an engine singleton.
-	assert_equal(example.test_use_engine_singleton(), OS.get_name())
+	# Test that we can access an engine singletons.
+	assert_equal(example.test_use_engine_singleton1(), OS.get_name())
+	assert_equal(example.test_use_engine_singleton2(), true)
 
 	# Test that we can access the SceneTree singleton.
 	assert_equal(example.test_use_scene_tree_singleton(), true)

test/src/example.cpp

@@ -7,12 +7,14 @@
 
 #include <godot_cpp/core/class_db.hpp>
 
+#include <godot_cpp/classes/engine.hpp>
 #include <godot_cpp/classes/global_constants.hpp>
 #include <godot_cpp/classes/label.hpp>
 #include <godot_cpp/classes/multiplayer_api.hpp>
 #include <godot_cpp/classes/multiplayer_peer.hpp>
 #include <godot_cpp/classes/os.hpp>
 #include <godot_cpp/classes/scene_tree.hpp>
+#include <godot_cpp/classes/xr_server.hpp>
 #include <godot_cpp/variant/utility_functions.hpp>
 
 using namespace godot;
@@ -269,6 +271,9 @@ void Example::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("test_use_engine_singleton"), &Example::test_use_engine_singleton);
 	ClassDB::bind_method(D_METHOD("test_use_scene_tree_singleton"), &Example::test_use_scene_tree_singleton);
 
+	ClassDB::bind_method(D_METHOD("test_use_engine_singleton1"), &Example::test_use_engine_singleton1);
+	ClassDB::bind_method(D_METHOD("test_use_engine_singleton2"), &Example::test_use_engine_singleton2);
+
 	ClassDB::bind_method(D_METHOD("test_get_internal_class"), &Example::test_get_internal_class);
 
 	ClassDB::bind_static_method("Example", D_METHOD("test_static", "a", "b"), &Example::test_static);
@@ -757,15 +762,20 @@ String Example::test_virtual_implemented_in_script(const String &p_name, int p_v
 	return "Unimplemented";
 }
 
-String Example::test_use_engine_singleton() const {
-	return OS::get_singleton()->get_name();
-}
-
 bool Example::test_use_scene_tree_singleton() const {
 	SceneTree *scene_tree = SceneTree::get_singleton();
 	return scene_tree != nullptr && scene_tree == get_tree();
 }
 
+String Example::test_use_engine_singleton1() const {
+	return OS::get_singleton()->get_name();
+}
+
+bool Example::test_use_engine_singleton2() const {
+	XRServer *xr_server = Object::cast_to<XRServer>(Engine::get_singleton()->get_singleton("XRServer"));
+	return xr_server != nullptr;
+}
+
 String Example::test_library_path() {
 	String library_path;
 	::godot::gdextension_interface::get_library_path(::godot::gdextension_interface::library, library_path._native_ptr());

test/src/example.h

@@ -216,6 +216,9 @@ class Example : public Control {
 	String test_use_engine_singleton() const;
 	bool test_use_scene_tree_singleton() const;
 
+	String test_use_engine_singleton1() const;
+	bool test_use_engine_singleton2() const;
+
 	static String test_library_path();
 
 	Ref<RefCounted> test_get_internal_class() const;