Allow instantiate unexposed EditorPlugin form GDExtension.

core/object/class_db.cpp

@@ -533,19 +533,21 @@ StringName ClassDB::get_compatibility_class(const StringName &p_class) {
 	return StringName();
 }
 
-Object *ClassDB::_instantiate_internal(const StringName &p_class, bool p_require_real_class, bool p_notify_postinitialize) {
+Object *ClassDB::_instantiate_internal(const StringName &p_class, bool p_require_real_class, bool p_notify_postinitialize, bool p_exposed_only) {
 	ClassInfo *ti;
 	{
 		Locker::Lock lock(Locker::STATE_READ);
 		ti = classes.getptr(p_class);
-		if (!_can_instantiate(ti)) {
+		if (!_can_instantiate(ti, p_exposed_only)) {
 			if (compat_classes.has(p_class)) {
 				ti = classes.getptr(compat_classes[p_class]);
 			}
 		}
 		ERR_FAIL_NULL_V_MSG(ti, nullptr, vformat("Cannot get class '%s'.", String(p_class)));
 		ERR_FAIL_COND_V_MSG(ti->disabled, nullptr, vformat("Class '%s' is disabled.", String(p_class)));
-		ERR_FAIL_COND_V_MSG(!ti->exposed, nullptr, vformat("Class '%s' isn't exposed.", String(p_class)));
+		if (p_exposed_only) {
+			ERR_FAIL_COND_V_MSG(!ti->exposed, nullptr, vformat("Class '%s' isn't exposed.", String(p_class)));
+		}
 		ERR_FAIL_NULL_V_MSG(ti->creation_func, nullptr, vformat("Class '%s' or its base class cannot be instantiated.", String(p_class)));
 	}
 
@@ -597,12 +599,16 @@ Object *ClassDB::_instantiate_internal(const StringName &p_class, bool p_require
 	}
 }
 
-bool ClassDB::_can_instantiate(ClassInfo *p_class_info) {
+bool ClassDB::_can_instantiate(ClassInfo *p_class_info, bool p_exposed_only) {
 	if (!p_class_info) {
 		return false;
 	}
 
-	if (p_class_info->disabled || !p_class_info->exposed || !p_class_info->creation_func) {
+	if (p_exposed_only && !p_class_info->exposed) {
+		return false;
+	}
+
+	if (p_class_info->disabled || !p_class_info->creation_func) {
 		return false;
 	}
 
@@ -2337,6 +2343,10 @@ uint64_t ClassDB::get_native_struct_size(const StringName &p_name) {
 	return native_structs[p_name].struct_size;
 }
 
+Object *ClassDB::_instantiate_allow_unexposed(const StringName &p_class) {
+	return _instantiate_internal(p_class, false, true, false);
+}
+
 void ClassDB::cleanup_defaults() {
 	default_values.clear();
 	default_values_cached.clear();

core/object/class_db.h

@@ -216,9 +216,9 @@ private:
 	static MethodBind *_bind_vararg_method(MethodBind *p_bind, const StringName &p_name, const Vector<Variant> &p_default_args, bool p_compatibility);
 	static void _bind_method_custom(const StringName &p_class, MethodBind *p_method, bool p_compatibility);
 
-	static Object *_instantiate_internal(const StringName &p_class, bool p_require_real_class = false, bool p_notify_postinitialize = true);
+	static Object *_instantiate_internal(const StringName &p_class, bool p_require_real_class = false, bool p_notify_postinitialize = true, bool p_exposed_only = true);
 
-	static bool _can_instantiate(ClassInfo *p_class_info);
+	static bool _can_instantiate(ClassInfo *p_class_info, bool p_exposed_only = true);
 
 public:
 	// DO NOT USE THIS!!!!!! NEEDS TO BE PUBLIC BUT DO NOT USE NO MATTER WHAT!!!
@@ -520,6 +520,8 @@ public:
 	static void get_native_struct_list(List<StringName> *r_names);
 	static String get_native_struct_code(const StringName &p_name);
 	static uint64_t get_native_struct_size(const StringName &p_name); // Used for asserting
+
+	static Object *_instantiate_allow_unexposed(const StringName &p_class); // Used to create unexposed classes from GDExtension, typically for unexposed EditorPlugin.
 };
 
 #define BIND_ENUM_CONSTANT(m_constant) \

editor/editor_node.cpp

@@ -3786,7 +3786,7 @@ void EditorNode::add_extension_editor_plugin(const StringName &p_class_name) {
 	ERR_FAIL_COND_MSG(!ClassDB::is_parent_class(p_class_name, SNAME("EditorPlugin")), vformat("Class is not an editor plugin: %s", p_class_name));
 	ERR_FAIL_COND_MSG(singleton->editor_data.has_extension_editor_plugin(p_class_name), vformat("Editor plugin already added for class: %s", p_class_name));
 
-	EditorPlugin *plugin = Object::cast_to<EditorPlugin>(ClassDB::instantiate(p_class_name));
+	EditorPlugin *plugin = Object::cast_to<EditorPlugin>(ClassDB::_instantiate_allow_unexposed(p_class_name));
 	singleton->editor_data.add_extension_editor_plugin(p_class_name, plugin);
 	add_editor_plugin(plugin);
 }