Merge pull request #38723 from neikeq/initial-classdb-test

Added tests for ClassDB

main/tests/test_class_db.cpp

@@ -0,0 +1,882 @@
+/*************************************************************************/
+/*  test_class_db.cpp                                                    */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "test_class_db.h"
+
+#include "core/global_constants.h"
+#include "core/ordered_hash_map.h"
+#include "core/os/os.h"
+#include "core/string_name.h"
+#include "core/ustring.h"
+#include "core/variant.h"
+
+namespace TestClassDB {
+
+enum class [[nodiscard]] TestResult{
+	FAILED,
+	PASS
+};
+
+#define TEST_FAIL_COND_FATAL(m_cond, m_msg) \
+	if (unlikely(m_cond)) {                 \
+		ERR_PRINT(m_msg);                   \
+		return TestResult::FAILED;          \
+	} else                                  \
+		((void)0)
+
+#define TEST_FAIL_COND(m_cond, m_msg)         \
+	if (unlikely(m_cond)) {                   \
+		ERR_PRINT(m_msg);                     \
+		__test_result__ = TestResult::FAILED; \
+	} else                                    \
+		((void)0)
+
+#define TEST_CHECK_FATAL(m_test_expr)                    \
+	if (unlikely((m_test_expr) == TestResult::FAILED)) { \
+		return TestResult::FAILED;                       \
+	} else                                               \
+		((void)0)
+
+#define TEST_CHECK(m_test_expr)                          \
+	if (unlikely((m_test_expr) == TestResult::FAILED)) { \
+		__test_result__ = TestResult::FAILED;            \
+	} else                                               \
+		((void)0)
+
+#define TEST_START()                               \
+	TestResult __test_result__ = TestResult::PASS; \
+	((void)0)
+
+#define TEST_END() return __test_result__;
+
+struct TypeReference {
+	StringName name;
+	bool is_enum = false;
+};
+
+struct ConstantData {
+	String name;
+	int value = 0;
+};
+
+struct EnumData {
+	StringName name;
+	List<ConstantData> constants;
+
+	_FORCE_INLINE_ bool operator==(const EnumData &p_enum) const {
+		return p_enum.name == name;
+	}
+};
+
+struct PropertyData {
+	StringName name;
+	int index = 0;
+
+	StringName getter;
+	StringName setter;
+};
+
+struct ArgumentData {
+	TypeReference type;
+	String name;
+	bool has_defval = false;
+	Variant defval;
+};
+
+struct MethodData {
+	StringName name;
+	TypeReference return_type;
+	List<ArgumentData> arguments;
+	bool is_virtual = false;
+	bool is_vararg = false;
+};
+
+struct SignalData {
+	StringName name;
+	List<ArgumentData> arguments;
+};
+
+struct ExposedClass {
+	StringName name;
+	StringName base;
+
+	bool is_singleton = false;
+	bool is_instantiable = false;
+	bool is_reference = false;
+
+	ClassDB::APIType api_type;
+
+	List<ConstantData> constants;
+	List<EnumData> enums;
+	List<PropertyData> properties;
+	List<MethodData> methods;
+	List<SignalData> signals_;
+
+	const PropertyData *find_property_by_name(const StringName &p_name) const {
+		for (const List<PropertyData>::Element *E = properties.front(); E; E = E->next()) {
+			if (E->get().name == p_name) {
+				return &E->get();
+			}
+		}
+
+		return nullptr;
+	}
+
+	const MethodData *find_method_by_name(const StringName &p_name) const {
+		for (const List<MethodData>::Element *E = methods.front(); E; E = E->next()) {
+			if (E->get().name == p_name) {
+				return &E->get();
+			}
+		}
+
+		return nullptr;
+	}
+};
+
+struct NamesCache {
+	StringName variant_type = StaticCString::create("Variant");
+	StringName object_class = StaticCString::create("Object");
+	StringName reference_class = StaticCString::create("Reference");
+	StringName string_type = StaticCString::create("String");
+	StringName string_name_type = StaticCString::create("StringName");
+	StringName node_path_type = StaticCString::create("NodePath");
+	StringName bool_type = StaticCString::create("bool");
+	StringName int_type = StaticCString::create("int");
+	StringName float_type = StaticCString::create("float");
+	StringName void_type = StaticCString::create("void");
+	StringName vararg_stub_type = StaticCString::create("@VarArg@");
+	StringName vector2_type = StaticCString::create("Vector2");
+	StringName rect2_type = StaticCString::create("Rect2");
+	StringName vector3_type = StaticCString::create("Vector3");
+
+	// Object not included as it must be checked for all derived classes
+	static constexpr int nullable_types_count = 17;
+	StringName nullable_types[nullable_types_count] = {
+		string_type,
+		string_name_type,
+		node_path_type,
+
+		StaticCString::create(_STR(Array)),
+		StaticCString::create(_STR(Dictionary)),
+		StaticCString::create(_STR(Callable)),
+		StaticCString::create(_STR(Signal)),
+
+		StaticCString::create(_STR(PackedByteArray)),
+		StaticCString::create(_STR(PackedInt32Array)),
+		StaticCString::create(_STR(PackedInt64rray)),
+		StaticCString::create(_STR(PackedFloat32Array)),
+		StaticCString::create(_STR(PackedFloat64Array)),
+		StaticCString::create(_STR(PackedStringArray)),
+		StaticCString::create(_STR(PackedVector2Array)),
+		StaticCString::create(_STR(PackedVector3Array)),
+		StaticCString::create(_STR(PackedColorArray)),
+	};
+
+	bool is_nullable_type(const StringName &p_type) const {
+		for (int i = 0; i < nullable_types_count; i++) {
+			if (p_type == nullable_types[i]) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+};
+
+typedef OrderedHashMap<StringName, ExposedClass> ExposedClasses;
+
+struct Context {
+	Vector<StringName> enum_types;
+	Vector<StringName> builtin_types;
+	ExposedClasses exposed_classes;
+	List<EnumData> global_enums;
+	NamesCache names_cache;
+
+	const ExposedClass *find_exposed_class(const StringName &p_name) const {
+		ExposedClasses::ConstElement elem = exposed_classes.find(p_name);
+		return elem ? &elem.value() : nullptr;
+	}
+
+	const ExposedClass *find_exposed_class(const TypeReference &p_type_ref) const {
+		ExposedClasses::ConstElement elem = exposed_classes.find(p_type_ref.name);
+		return elem ? &elem.value() : nullptr;
+	}
+
+	bool has_type(const Context &p_context, const TypeReference &p_type_ref) const {
+		if (p_context.builtin_types.find(p_type_ref.name) >= 0) {
+			return true;
+		}
+
+		if (p_type_ref.is_enum) {
+			if (p_context.enum_types.find(p_type_ref.name) >= 0) {
+				return true;
+			}
+
+			// Enum not found. Most likely because none of its constants were bound, so it's empty. That's fine. Use int instead.
+			return p_context.builtin_types.find(p_context.names_cache.int_type);
+		}
+
+		return false;
+	}
+};
+
+bool arg_default_value_is_assignable_to_type(const Context &p_context, const Variant &p_val, const TypeReference &p_arg_type) {
+	if (p_arg_type.name == p_context.names_cache.variant_type) {
+		// Variant can take anything
+		return true;
+	}
+
+	switch (p_val.get_type()) {
+		case Variant::NIL:
+			return p_context.find_exposed_class(p_arg_type) ||
+				   p_context.names_cache.is_nullable_type(p_arg_type.name);
+		case Variant::BOOL:
+			return p_arg_type.name == p_context.names_cache.bool_type;
+		case Variant::INT:
+			return p_arg_type.name == p_context.names_cache.int_type ||
+				   p_arg_type.name == p_context.names_cache.float_type ||
+				   p_arg_type.is_enum;
+		case Variant::FLOAT:
+			return p_arg_type.name == p_context.names_cache.float_type;
+		case Variant::STRING:
+		case Variant::STRING_NAME:
+			return p_arg_type.name == p_context.names_cache.string_type ||
+				   p_arg_type.name == p_context.names_cache.string_name_type ||
+				   p_arg_type.name == p_context.names_cache.node_path_type;
+		case Variant::NODE_PATH:
+			return p_arg_type.name == p_context.names_cache.node_path_type;
+		case Variant::TRANSFORM:
+		case Variant::TRANSFORM2D:
+		case Variant::BASIS:
+		case Variant::QUAT:
+		case Variant::PLANE:
+		case Variant::AABB:
+		case Variant::COLOR:
+		case Variant::VECTOR2:
+		case Variant::RECT2:
+		case Variant::VECTOR3:
+		case Variant::_RID:
+		case Variant::ARRAY:
+		case Variant::DICTIONARY:
+		case Variant::PACKED_BYTE_ARRAY:
+		case Variant::PACKED_INT32_ARRAY:
+		case Variant::PACKED_INT64_ARRAY:
+		case Variant::PACKED_FLOAT32_ARRAY:
+		case Variant::PACKED_FLOAT64_ARRAY:
+		case Variant::PACKED_STRING_ARRAY:
+		case Variant::PACKED_VECTOR2_ARRAY:
+		case Variant::PACKED_VECTOR3_ARRAY:
+		case Variant::PACKED_COLOR_ARRAY:
+		case Variant::CALLABLE:
+		case Variant::SIGNAL:
+			return p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::OBJECT:
+			return p_context.find_exposed_class(p_arg_type);
+		case Variant::VECTOR2I:
+			return p_arg_type.name == p_context.names_cache.vector2_type ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::RECT2I:
+			return p_arg_type.name == p_context.names_cache.rect2_type ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		case Variant::VECTOR3I:
+			return p_arg_type.name == p_context.names_cache.vector3_type ||
+				   p_arg_type.name == Variant::get_type_name(p_val.get_type());
+		default:
+			ERR_PRINT("Unexpected Variant type: " + itos(p_val.get_type()));
+			break;
+	}
+
+	return false;
+}
+
+TestResult validate_property(const Context &p_context, const ExposedClass &p_class, const PropertyData &p_prop) {
+	TEST_START();
+
+	const MethodData *setter = p_class.find_method_by_name(p_prop.setter);
+
+	// Search it in base classes too
+	const ExposedClass *top = &p_class;
+	while (!setter && top->base != StringName()) {
+		top = p_context.find_exposed_class(top->base);
+		TEST_FAIL_COND(!top, "Class not found '" + top->base + "'. Inherited by '" + top->name + "'.");
+		setter = top->find_method_by_name(p_prop.setter);
+	}
+
+	const MethodData *getter = p_class.find_method_by_name(p_prop.getter);
+
+	// Search it in base classes too
+	top = &p_class;
+	while (!getter && top->base != StringName()) {
+		top = p_context.find_exposed_class(top->base);
+		TEST_FAIL_COND(!top, "Class not found '" + top->base + "'. Inherited by '" + top->name + "'.");
+		getter = top->find_method_by_name(p_prop.getter);
+	}
+
+	TEST_FAIL_COND(!setter && !getter,
+			"Couldn't find neither the setter nor the getter for property: '" + p_class.name + "." + String(p_prop.name) + "'.");
+
+	if (setter) {
+		int setter_argc = p_prop.index != -1 ? 2 : 1;
+		TEST_FAIL_COND(setter->arguments.size() != setter_argc,
+				"Invalid property setter argument count: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	}
+
+	if (getter) {
+		int getter_argc = p_prop.index != -1 ? 1 : 0;
+		TEST_FAIL_COND(getter->arguments.size() != getter_argc,
+				"Invalid property setter argument count: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	}
+
+	if (getter && setter) {
+		const ArgumentData &setter_first_arg = setter->arguments.back()->get();
+		if (getter->return_type.name != setter_first_arg.type.name) {
+			// Special case for Node::set_name
+			bool whitelisted = getter->return_type.name == p_context.names_cache.string_name_type &&
+							   setter_first_arg.type.name == p_context.names_cache.string_type;
+
+			TEST_FAIL_COND(!whitelisted,
+					"Return type from getter doesn't match first argument of setter, for property: '" + p_class.name + "." + String(p_prop.name) + "'.");
+		}
+	}
+
+	const TypeReference &prop_type_ref = getter ? getter->return_type : setter->arguments.back()->get().type;
+
+	const ExposedClass *prop_class = p_context.find_exposed_class(prop_type_ref);
+	if (prop_class) {
+		TEST_FAIL_COND(prop_class->is_singleton,
+				"Property type is a singleton: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	} else {
+		TEST_FAIL_COND(!p_context.has_type(p_context, prop_type_ref),
+				"Property type '" + prop_type_ref.name + "' not found: '" + p_class.name + "." + String(p_prop.name) + "'.");
+	}
+
+	if (getter) {
+		if (p_prop.index != -1) {
+			const ArgumentData &idx_arg = getter->arguments.front()->get();
+			if (idx_arg.type.name != p_context.names_cache.int_type) {
+				// If not an int, it can be an enum
+				TEST_FAIL_COND(p_context.enum_types.find(idx_arg.type.name) < 0,
+						"Invalid type '" + idx_arg.type.name + "' for index argument of property getter: '" + p_class.name + "." + String(p_prop.name) + "'.");
+			}
+		}
+	}
+
+	if (setter) {
+		if (p_prop.index != -1) {
+			const ArgumentData &idx_arg = setter->arguments.front()->get();
+			if (idx_arg.type.name != p_context.names_cache.int_type) {
+				// Assume the index parameter is an enum
+				// If not an int, it can be an enum
+				TEST_FAIL_COND(p_context.enum_types.find(idx_arg.type.name) < 0,
+						"Invalid type '" + idx_arg.type.name + "' for index argument of property setter: '" + p_class.name + "." + String(p_prop.name) + "'.");
+			}
+		}
+	}
+
+	TEST_END();
+}
+
+TestResult validate_method(const Context &p_context, const ExposedClass &p_class, const MethodData &p_method) {
+	TEST_START();
+
+	const ExposedClass *return_class = p_context.find_exposed_class(p_method.return_type);
+	if (return_class) {
+		TEST_FAIL_COND(return_class->is_singleton,
+				"Method return type is a singleton: '" + p_class.name + "." + p_method.name + "'.");
+	}
+
+	for (const List<ArgumentData>::Element *F = p_method.arguments.front(); F; F = F->next()) {
+		const ArgumentData &arg = F->get();
+
+		const ExposedClass *arg_class = p_context.find_exposed_class(arg.type);
+		if (arg_class) {
+			TEST_FAIL_COND(arg_class->is_singleton,
+					"Argument type is a singleton: '" + arg.name + "' of method '" + p_class.name + "." + p_method.name + "'.");
+		} else {
+			TEST_FAIL_COND(!p_context.has_type(p_context, arg.type),
+					"Argument type '" + arg.type.name + "' not found: '" + arg.name + "' of method" + p_class.name + "." + p_method.name + "'.");
+		}
+
+		if (arg.has_defval) {
+			TEST_FAIL_COND(!arg_default_value_is_assignable_to_type(p_context, arg.defval, arg.type),
+					"Invalid default value for parameter '" + arg.name + "' of method '" + p_class.name + "." + p_method.name + "'.");
+		}
+	}
+
+	TEST_END();
+}
+
+TestResult validate_signal(const Context &p_context, const ExposedClass &p_class, const SignalData &p_signal) {
+	TEST_START();
+
+	for (const List<ArgumentData>::Element *F = p_signal.arguments.front(); F; F = F->next()) {
+		const ArgumentData &arg = F->get();
+
+		const ExposedClass *arg_class = p_context.find_exposed_class(arg.type);
+		if (arg_class) {
+			TEST_FAIL_COND(arg_class->is_singleton,
+					"Argument class is a singleton: '" + arg.name + "' of signal" + p_class.name + "." + p_signal.name + "'.");
+		} else {
+			TEST_FAIL_COND(!p_context.has_type(p_context, arg.type),
+					"Argument type '" + arg.type.name + "' not found: '" + arg.name + "' of signal" + p_class.name + "." + p_signal.name + "'.");
+		}
+	}
+
+	TEST_END();
+}
+
+TestResult validate_class(const Context &p_context, const ExposedClass &p_exposed_class) {
+	TEST_START();
+
+	bool is_derived_type = p_exposed_class.base != StringName();
+
+	if (!is_derived_type) {
+		// Asserts about the base Object class
+		TEST_FAIL_COND_FATAL(p_exposed_class.name != p_context.names_cache.object_class,
+				"Class '" + p_exposed_class.name + "' has no base class.");
+		TEST_FAIL_COND_FATAL(!p_exposed_class.is_instantiable,
+				"Object class is not instantiable.");
+		TEST_FAIL_COND_FATAL(p_exposed_class.api_type != ClassDB::API_CORE,
+				"Object class is API is not API_CORE.");
+		TEST_FAIL_COND_FATAL(p_exposed_class.is_singleton,
+				"Object class is registered as a singleton.");
+	}
+
+	CRASH_COND_MSG(p_exposed_class.is_singleton && p_exposed_class.base != p_context.names_cache.object_class,
+			"Singleton base class '" + String(p_exposed_class.base) + "' is not Object, for class '" + p_exposed_class.name + "'.");
+
+	CRASH_COND_MSG(is_derived_type && !p_context.exposed_classes.has(p_exposed_class.base),
+			"Base type '" + p_exposed_class.base.operator String() + "' does not exist, for class '" + p_exposed_class.name + "'.");
+
+	for (const List<PropertyData>::Element *F = p_exposed_class.properties.front(); F; F = F->next()) {
+		TEST_CHECK(validate_property(p_context, p_exposed_class, F->get()));
+	}
+
+	for (const List<MethodData>::Element *F = p_exposed_class.methods.front(); F; F = F->next()) {
+		TEST_CHECK(validate_method(p_context, p_exposed_class, F->get()));
+	}
+
+	for (const List<SignalData>::Element *F = p_exposed_class.signals_.front(); F; F = F->next()) {
+		TEST_CHECK(validate_signal(p_context, p_exposed_class, F->get()));
+	}
+
+	TEST_END();
+}
+
+TestResult add_exposed_classes(Context &r_context) {
+	TEST_START();
+
+	List<StringName> class_list;
+	ClassDB::get_class_list(&class_list);
+	class_list.sort_custom<StringName::AlphCompare>();
+
+	while (class_list.size()) {
+		StringName class_name = class_list.front()->get();
+
+		ClassDB::APIType api_type = ClassDB::get_api_type(class_name);
+
+		if (api_type == ClassDB::API_NONE) {
+			class_list.pop_front();
+			continue;
+		}
+
+		if (!ClassDB::is_class_exposed(class_name)) {
+			OS::get_singleton()->print("Ignoring class '%s' because it's not exposed\n", String(class_name).utf8().get_data());
+			class_list.pop_front();
+			continue;
+		}
+
+		if (!ClassDB::is_class_enabled(class_name)) {
+			OS::get_singleton()->print("Ignoring class '%s' because it's not enabled\n", String(class_name).utf8().get_data());
+			class_list.pop_front();
+			continue;
+		}
+
+		ClassDB::ClassInfo *class_info = ClassDB::classes.getptr(class_name);
+
+		ExposedClass exposed_class;
+		exposed_class.name = class_name;
+		exposed_class.api_type = api_type;
+		exposed_class.is_singleton = Engine::get_singleton()->has_singleton(class_name);
+		exposed_class.is_instantiable = class_info->creation_func && !exposed_class.is_singleton;
+		exposed_class.is_reference = ClassDB::is_parent_class(class_name, "Reference");
+		exposed_class.base = ClassDB::get_parent_class(class_name);
+
+		// Add properties
+
+		List<PropertyInfo> property_list;
+		ClassDB::get_property_list(class_name, &property_list, true);
+
+		Map<StringName, StringName> accessor_methods;
+
+		for (const List<PropertyInfo>::Element *E = property_list.front(); E; E = E->next()) {
+			const PropertyInfo &property = E->get();
+
+			if (property.usage & PROPERTY_USAGE_GROUP || property.usage & PROPERTY_USAGE_SUBGROUP || property.usage & PROPERTY_USAGE_CATEGORY) {
+				continue;
+			}
+
+			PropertyData prop;
+			prop.name = property.name;
+			prop.setter = ClassDB::get_property_setter(class_name, prop.name);
+			prop.getter = ClassDB::get_property_getter(class_name, prop.name);
+
+			if (prop.setter != StringName()) {
+				accessor_methods[prop.setter] = prop.name;
+			}
+			if (prop.getter != StringName()) {
+				accessor_methods[prop.getter] = prop.name;
+			}
+
+			bool valid = false;
+			prop.index = ClassDB::get_property_index(class_name, prop.name, &valid);
+			TEST_FAIL_COND(!valid, "Invalid property: '" + exposed_class.name + "." + String(prop.name) + "'.");
+
+			exposed_class.properties.push_back(prop);
+		}
+
+		// Add methods
+
+		List<MethodInfo> virtual_method_list;
+		ClassDB::get_virtual_methods(class_name, &virtual_method_list, true);
+
+		List<MethodInfo> method_list;
+		ClassDB::get_method_list(class_name, &method_list, true);
+		method_list.sort();
+
+		for (List<MethodInfo>::Element *E = method_list.front(); E; E = E->next()) {
+			const MethodInfo &method_info = E->get();
+
+			int argc = method_info.arguments.size();
+
+			if (method_info.name.empty()) {
+				continue;
+			}
+
+			MethodData method;
+			method.name = method_info.name;
+
+			if (method_info.flags & METHOD_FLAG_VIRTUAL) {
+				method.is_virtual = true;
+			}
+
+			PropertyInfo return_info = method_info.return_val;
+
+			MethodBind *m = method.is_virtual ? nullptr : ClassDB::get_method(class_name, method_info.name);
+
+			method.is_vararg = m && m->is_vararg();
+
+			if (!m && !method.is_virtual) {
+				TEST_FAIL_COND(!virtual_method_list.find(method_info),
+						"Missing MethodBind for non-virtual method: '" + exposed_class.name + "." + method.name + "'.");
+
+				// A virtual method without the virtual flag. This is a special case.
+
+				// The method Object.free is registered as a virtual method, but without the virtual flag.
+				// This is because this method is not supposed to be overridden, but called.
+				// We assume the return type is void.
+				method.return_type.name = r_context.names_cache.void_type;
+
+				// Actually, more methods like this may be added in the future, which could return
+				// something different. Let's put this check to notify us if that ever happens.
+				if (exposed_class.name != r_context.names_cache.object_class || String(method.name) != "free") {
+					WARN_PRINT("Notification: New unexpected virtual non-overridable method found."
+							   " We only expected Object.free, but found '" +
+							   exposed_class.name + "." + method.name + "'.");
+				}
+			} else if (return_info.type == Variant::INT && return_info.usage & PROPERTY_USAGE_CLASS_IS_ENUM) {
+				method.return_type.name = return_info.class_name;
+				method.return_type.is_enum = true;
+			} else if (return_info.class_name != StringName()) {
+				method.return_type.name = return_info.class_name;
+
+				bool bad_reference_hint = !method.is_virtual && return_info.hint != PROPERTY_HINT_RESOURCE_TYPE &&
+										  ClassDB::is_parent_class(return_info.class_name, r_context.names_cache.reference_class);
+				TEST_FAIL_COND(bad_reference_hint, String() + "Return type is reference but hint is not '" _STR(PROPERTY_HINT_RESOURCE_TYPE) "'." +
+														   " Are you returning a reference type by pointer? Method: '" +
+														   exposed_class.name + "." + method.name + "'.");
+			} else if (return_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
+				method.return_type.name = return_info.hint_string;
+			} else if (return_info.type == Variant::NIL && return_info.usage & PROPERTY_USAGE_NIL_IS_VARIANT) {
+				method.return_type.name = r_context.names_cache.variant_type;
+			} else if (return_info.type == Variant::NIL) {
+				method.return_type.name = r_context.names_cache.void_type;
+			} else {
+				// NOTE: We don't care about the size and sign of int and float in these tests
+				method.return_type.name = Variant::get_type_name(return_info.type);
+			}
+
+			for (int i = 0; i < argc; i++) {
+				PropertyInfo arg_info = method_info.arguments[i];
+
+				String orig_arg_name = arg_info.name;
+
+				ArgumentData arg;
+				arg.name = orig_arg_name;
+
+				if (arg_info.type == Variant::INT && arg_info.usage & PROPERTY_USAGE_CLASS_IS_ENUM) {
+					arg.type.name = arg_info.class_name;
+					arg.type.is_enum = true;
+				} else if (arg_info.class_name != StringName()) {
+					arg.type.name = arg_info.class_name;
+				} else if (arg_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
+					arg.type.name = arg_info.hint_string;
+				} else if (arg_info.type == Variant::NIL) {
+					arg.type.name = r_context.names_cache.variant_type;
+				} else {
+					// NOTE: We don't care about the size and sign of int and float in these tests
+					arg.type.name = Variant::get_type_name(arg_info.type);
+				}
+
+				if (m && m->has_default_argument(i)) {
+					arg.has_defval = true;
+					arg.defval = m->get_default_argument(i);
+				}
+
+				method.arguments.push_back(arg);
+			}
+
+			if (method.is_vararg) {
+				ArgumentData vararg;
+				vararg.type.name = r_context.names_cache.vararg_stub_type;
+				vararg.name = "@varargs@";
+				method.arguments.push_back(vararg);
+			}
+
+			TEST_FAIL_COND(exposed_class.find_property_by_name(method.name),
+					"Method name conflicts with property: '" + String(class_name) + "." + String(method.name) + "'.");
+
+			// Classes starting with an underscore are ignored unless they're used as a property setter or getter
+			if (!method.is_virtual && String(method.name)[0] == '_') {
+				for (const List<PropertyData>::Element *F = exposed_class.properties.front(); F; F = F->next()) {
+					const PropertyData &prop = F->get();
+
+					if (prop.setter == method.name || prop.getter == method.name) {
+						exposed_class.methods.push_back(method);
+						break;
+					}
+				}
+			} else {
+				exposed_class.methods.push_back(method);
+			}
+		}
+
+		// Add signals
+
+		const HashMap<StringName, MethodInfo> &signal_map = class_info->signal_map;
+		const StringName *k = nullptr;
+
+		while ((k = signal_map.next(k))) {
+			SignalData signal;
+
+			const MethodInfo &method_info = signal_map.get(*k);
+
+			signal.name = method_info.name;
+
+			int argc = method_info.arguments.size();
+
+			for (int i = 0; i < argc; i++) {
+				PropertyInfo arg_info = method_info.arguments[i];
+
+				String orig_arg_name = arg_info.name;
+
+				ArgumentData arg;
+				arg.name = orig_arg_name;
+
+				if (arg_info.type == Variant::INT && arg_info.usage & PROPERTY_USAGE_CLASS_IS_ENUM) {
+					arg.type.name = arg_info.class_name;
+					arg.type.is_enum = true;
+				} else if (arg_info.class_name != StringName()) {
+					arg.type.name = arg_info.class_name;
+				} else if (arg_info.hint == PROPERTY_HINT_RESOURCE_TYPE) {
+					arg.type.name = arg_info.hint_string;
+				} else if (arg_info.type == Variant::NIL) {
+					arg.type.name = r_context.names_cache.variant_type;
+				} else {
+					// NOTE: We don't care about the size and sign of int and float in these tests
+					arg.type.name = Variant::get_type_name(arg_info.type);
+				}
+
+				signal.arguments.push_back(arg);
+			}
+
+			bool method_conflict = exposed_class.find_property_by_name(signal.name);
+
+			if (method_conflict || exposed_class.find_method_by_name(signal.name)) {
+				// TODO:
+				// ClassDB allows signal names that conflict with method or property names.
+				// However registering a signal with a conflicting name is still considered wrong.
+				// Unfortunately there are some existing cases that are yet to be fixed.
+				// Until those are fixed we will print a warning instead of failing the test.
+				WARN_PRINT("Signal name conflicts with " + String(method_conflict ? "method" : "property") +
+						   ": '" + String(class_name) + "." + String(signal.name) + "'.");
+			}
+
+			exposed_class.signals_.push_back(signal);
+		}
+
+		// Add enums and constants
+
+		List<String> constants;
+		ClassDB::get_integer_constant_list(class_name, &constants, true);
+
+		const HashMap<StringName, List<StringName>> &enum_map = class_info->enum_map;
+		k = nullptr;
+
+		while ((k = enum_map.next(k))) {
+			EnumData enum_;
+			enum_.name = *k;
+
+			const List<StringName> &enum_constants = enum_map.get(*k);
+			for (const List<StringName>::Element *E = enum_constants.front(); E; E = E->next()) {
+				const StringName &constant_name = E->get();
+				int *value = class_info->constant_map.getptr(constant_name);
+				TEST_FAIL_COND(!value, "Missing enum constant value: '" +
+											   String(class_name) + "." + String(enum_.name) + "." + String(constant_name) + "'.");
+				constants.erase(constant_name);
+
+				ConstantData constant;
+				constant.name = constant_name;
+				constant.value = *value;
+
+				enum_.constants.push_back(constant);
+			}
+
+			exposed_class.enums.push_back(enum_);
+
+			r_context.enum_types.push_back(String(class_name) + "." + String(*k));
+		}
+
+		for (const List<String>::Element *E = constants.front(); E; E = E->next()) {
+			const String &constant_name = E->get();
+			int *value = class_info->constant_map.getptr(StringName(E->get()));
+			TEST_FAIL_COND(!value, "Missing enum constant value: '" + String(class_name) + "." + String(constant_name) + "'.");
+
+			ConstantData constant;
+			constant.name = constant_name;
+			constant.value = *value;
+
+			exposed_class.constants.push_back(constant);
+		}
+
+		r_context.exposed_classes.insert(class_name, exposed_class);
+		class_list.pop_front();
+	}
+
+	TEST_END();
+}
+
+void add_builtin_types(Context &r_context) {
+	// NOTE: We don't care about the size and sign of int and float in these tests
+	for (int i = 0; i < Variant::VARIANT_MAX; i++) {
+		r_context.builtin_types.push_back(Variant::get_type_name(Variant::Type(i)));
+	}
+
+	r_context.builtin_types.push_back(_STR(Variant));
+	r_context.builtin_types.push_back(r_context.names_cache.vararg_stub_type);
+	r_context.builtin_types.push_back("void");
+}
+
+void add_global_enums(Context &r_context) {
+	int global_constants_count = GlobalConstants::get_global_constant_count();
+
+	if (global_constants_count > 0) {
+		for (int i = 0; i < global_constants_count; i++) {
+			StringName enum_name = GlobalConstants::get_global_constant_enum(i);
+
+			if (enum_name != StringName()) {
+				ConstantData constant;
+				constant.name = GlobalConstants::get_global_constant_name(i);
+				constant.value = GlobalConstants::get_global_constant_value(i);
+
+				EnumData enum_;
+				enum_.name = enum_name;
+				List<EnumData>::Element *enum_match = r_context.global_enums.find(enum_);
+				if (enum_match) {
+					enum_match->get().constants.push_back(constant);
+				} else {
+					enum_.constants.push_back(constant);
+					r_context.global_enums.push_back(enum_);
+				}
+			}
+		}
+
+		for (List<EnumData>::Element *E = r_context.global_enums.front(); E; E = E->next()) {
+			r_context.enum_types.push_back(E->get().name);
+		}
+	}
+
+	// HARDCODED
+	List<StringName> hardcoded_enums;
+	hardcoded_enums.push_back("Vector2.Axis");
+	hardcoded_enums.push_back("Vector2i.Axis");
+	hardcoded_enums.push_back("Vector3.Axis");
+	hardcoded_enums.push_back("Vector3i.Axis");
+	for (List<StringName>::Element *E = hardcoded_enums.front(); E; E = E->next()) {
+		// These enums are not generated and must be written manually (e.g.: Vector3.Axis)
+		// Here, we assume core types do not begin with underscore
+		r_context.enum_types.push_back(E->get());
+	}
+}
+
+TestResult run_class_db_tests() {
+	TEST_START();
+
+	Context context;
+
+	TEST_CHECK_FATAL(add_exposed_classes(context));
+	add_builtin_types(context);
+	add_global_enums(context);
+
+	const ExposedClass *object_class = context.find_exposed_class(context.names_cache.object_class);
+	TEST_FAIL_COND_FATAL(!object_class, "Object class not found.");
+	TEST_FAIL_COND_FATAL(object_class->base != StringName(),
+			"Object class derives from another class: '" + object_class->base + "'.");
+
+	for (ExposedClasses::Element E = context.exposed_classes.front(); E; E = E.next()) {
+		TEST_CHECK(validate_class(context, E.value()));
+	}
+
+	TEST_END();
+}
+
+MainLoop *test() {
+	TestResult pass = run_class_db_tests();
+
+	OS::get_singleton()->print("ClassDB tests: %s\n", pass == TestResult::PASS ? "PASS" : "FAILED");
+
+	if (pass == TestResult::FAILED) {
+		OS::get_singleton()->set_exit_code(pass == TestResult::PASS ? 0 : 1);
+	}
+
+	return nullptr;
+}
+
+} // namespace TestClassDB

main/tests/test_class_db.h

@@ -0,0 +1,42 @@
+/*************************************************************************/
+/*  test_class_db.h                                                      */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef GODOT_TEST_CLASS_DB_H
+#define GODOT_TEST_CLASS_DB_H
+
+#include "core/os/main_loop.h"
+
+namespace TestClassDB {
+
+MainLoop *test();
+
+}
+
+#endif //GODOT_TEST_CLASS_DB_H

main/tests/test_main.cpp

@@ -35,6 +35,7 @@
 #ifdef DEBUG_ENABLED
 
 #include "test_astar.h"
+#include "test_class_db.h"
 #include "test_gdscript.h"
 #include "test_gui.h"
 #include "test_math.h"
@@ -54,6 +55,7 @@ const char **tests_get_names() {
 		"physics_3d",
 		"render",
 		"oa_hash_map",
+		"class_db",
 		"gui",
 		"shaderlang",
 		"gd_tokenizer",
@@ -93,6 +95,10 @@ MainLoop *test_main(String p_test, const List<String> &p_args) {
 		return TestOAHashMap::test();
 	}
 
+	if (p_test == "class_db") {
+		return TestClassDB::test();
+	}
+
 #ifndef _3D_DISABLED
 	if (p_test == "gui") {
 		return TestGUI::test();

modules/mono/editor/bindings_generator.h

@@ -102,6 +102,8 @@ class BindingsGenerator {
 		TypeReference type;
 
 		String name;
+
+		Variant def_param_value;
 		DefaultParamMode def_param_mode = CONSTANT;
 
 		/**
@@ -355,8 +357,9 @@ class BindingsGenerator {
 
 		const MethodInterface *find_method_by_name(const StringName &p_cname) const {
 			for (const List<MethodInterface>::Element *E = methods.front(); E; E = E->next()) {
-				if (E->get().cname == p_cname)
+				if (E->get().cname == p_cname) {
 					return &E->get();
+				}
 			}
 
 			return nullptr;
@@ -364,8 +367,9 @@ class BindingsGenerator {
 
 		const PropertyInterface *find_property_by_name(const StringName &p_cname) const {
 			for (const List<PropertyInterface>::Element *E = properties.front(); E; E = E->next()) {
-				if (E->get().cname == p_cname)
+				if (E->get().cname == p_cname) {
 					return &E->get();
+				}
 			}
 
 			return nullptr;
@@ -373,8 +377,9 @@ class BindingsGenerator {
 
 		const PropertyInterface *find_property_by_proxy_name(const String &p_proxy_name) const {
 			for (const List<PropertyInterface>::Element *E = properties.front(); E; E = E->next()) {
-				if (E->get().proxy_name == p_proxy_name)
+				if (E->get().proxy_name == p_proxy_name) {
 					return &E->get();
+				}
 			}
 
 			return nullptr;
@@ -382,8 +387,9 @@ class BindingsGenerator {
 
 		const MethodInterface *find_method_by_proxy_name(const String &p_proxy_name) const {
 			for (const List<MethodInterface>::Element *E = methods.front(); E; E = E->next()) {
-				if (E->get().proxy_name == p_proxy_name)
+				if (E->get().proxy_name == p_proxy_name) {
 					return &E->get();
+				}
 			}
 
 			return nullptr;
@@ -523,58 +529,70 @@ class BindingsGenerator {
 	void _initialize_blacklisted_methods();
 
 	struct NameCache {
-		StringName type_void;
-		StringName type_Array;
-		StringName type_Dictionary;
-		StringName type_Variant;
-		StringName type_VarArg;
-		StringName type_Object;
-		StringName type_Reference;
-		StringName type_RID;
-		StringName type_String;
-		StringName type_StringName;
-		StringName type_NodePath;
-		StringName type_at_GlobalScope;
-		StringName enum_Error;
-
-		StringName type_sbyte;
-		StringName type_short;
-		StringName type_int;
-		StringName type_long;
-		StringName type_byte;
-		StringName type_ushort;
-		StringName type_uint;
-		StringName type_ulong;
-		StringName type_float;
-		StringName type_double;
-
-		NameCache() {
-			type_void = StaticCString::create("void");
-			type_Array = StaticCString::create("Array");
-			type_Dictionary = StaticCString::create("Dictionary");
-			type_Variant = StaticCString::create("Variant");
-			type_VarArg = StaticCString::create("VarArg");
-			type_Object = StaticCString::create("Object");
-			type_Reference = StaticCString::create("Reference");
-			type_RID = StaticCString::create("RID");
-			type_String = StaticCString::create("String");
-			type_StringName = StaticCString::create("StringName");
-			type_NodePath = StaticCString::create("NodePath");
-			type_at_GlobalScope = StaticCString::create("@GlobalScope");
-			enum_Error = StaticCString::create("Error");
-
-			type_sbyte = StaticCString::create("sbyte");
-			type_short = StaticCString::create("short");
-			type_int = StaticCString::create("int");
-			type_long = StaticCString::create("long");
-			type_byte = StaticCString::create("byte");
-			type_ushort = StaticCString::create("ushort");
-			type_uint = StaticCString::create("uint");
-			type_ulong = StaticCString::create("ulong");
-			type_float = StaticCString::create("float");
-			type_double = StaticCString::create("double");
+		StringName type_void = StaticCString::create("void");
+		StringName type_Variant = StaticCString::create("Variant");
+		StringName type_VarArg = StaticCString::create("VarArg");
+		StringName type_Object = StaticCString::create("Object");
+		StringName type_Reference = StaticCString::create("Reference");
+		StringName type_RID = StaticCString::create("RID");
+		StringName type_String = StaticCString::create("String");
+		StringName type_StringName = StaticCString::create("StringName");
+		StringName type_NodePath = StaticCString::create("NodePath");
+		StringName type_at_GlobalScope = StaticCString::create("@GlobalScope");
+		StringName enum_Error = StaticCString::create("Error");
+
+		StringName type_sbyte = StaticCString::create("sbyte");
+		StringName type_short = StaticCString::create("short");
+		StringName type_int = StaticCString::create("int");
+		StringName type_byte = StaticCString::create("byte");
+		StringName type_ushort = StaticCString::create("ushort");
+		StringName type_uint = StaticCString::create("uint");
+		StringName type_long = StaticCString::create("long");
+		StringName type_ulong = StaticCString::create("ulong");
+
+		StringName type_bool = StaticCString::create("bool");
+		StringName type_float = StaticCString::create("float");
+		StringName type_double = StaticCString::create("double");
+
+		StringName type_Vector2 = StaticCString::create("Vector2");
+		StringName type_Rect2 = StaticCString::create("Rect2");
+		StringName type_Vector3 = StaticCString::create("Vector3");
+
+		// Object not included as it must be checked for all derived classes
+		static constexpr int nullable_types_count = 17;
+		StringName nullable_types[nullable_types_count] = {
+			type_String,
+			type_StringName,
+			type_NodePath,
+
+			StaticCString::create(_STR(Array)),
+			StaticCString::create(_STR(Dictionary)),
+			StaticCString::create(_STR(Callable)),
+			StaticCString::create(_STR(Signal)),
+
+			StaticCString::create(_STR(PackedByteArray)),
+			StaticCString::create(_STR(PackedInt32Array)),
+			StaticCString::create(_STR(PackedInt64rray)),
+			StaticCString::create(_STR(PackedFloat32Array)),
+			StaticCString::create(_STR(PackedFloat64Array)),
+			StaticCString::create(_STR(PackedStringArray)),
+			StaticCString::create(_STR(PackedVector2Array)),
+			StaticCString::create(_STR(PackedVector3Array)),
+			StaticCString::create(_STR(PackedColorArray)),
+		};
+
+		bool is_nullable_type(const StringName &p_type) const {
+			for (int i = 0; i < nullable_types_count; i++) {
+				if (p_type == nullable_types[i]) {
+					return true;
+				}
+			}
+
+			return false;
 		}
 
+		NameCache() {}
+
 	private:
 		NameCache(const NameCache &);
 		NameCache &operator=(const NameCache &);
@@ -585,8 +603,9 @@ class BindingsGenerator {
 	const List<InternalCall>::Element *find_icall_by_name(const String &p_name, const List<InternalCall> &p_list) {
 		const List<InternalCall>::Element *it = p_list.front();
 		while (it) {
-			if (it->get().name == p_name)
+			if (it->get().name == p_name) {
 				return it;
+			}
 			it = it->next();
 		}
 		return nullptr;
@@ -594,20 +613,22 @@ class BindingsGenerator {
 
 	const ConstantInterface *find_constant_by_name(const String &p_name, const List<ConstantInterface> &p_constants) const {
 		for (const List<ConstantInterface>::Element *E = p_constants.front(); E; E = E->next()) {
-			if (E->get().name == p_name)
+			if (E->get().name == p_name) {
 				return &E->get();
+			}
 		}
 
 		return nullptr;
 	}
 
 	inline String get_unique_sig(const TypeInterface &p_type) {
-		if (p_type.is_reference)
+		if (p_type.is_reference) {
 			return "Ref";
-		else if (p_type.is_object_type)
+		} else if (p_type.is_object_type) {
 			return "Obj";
-		else if (p_type.is_enum)
+		} else if (p_type.is_enum) {
 			return "int";
+		}
 
 		return p_type.name;
 	}
@@ -626,6 +647,7 @@ class BindingsGenerator {
 	StringName _get_float_type_name_from_meta(GodotTypeInfo::Metadata p_meta);
 
 	bool _arg_default_value_from_variant(const Variant &p_val, ArgumentInterface &r_iarg);
+	bool _arg_default_value_is_assignable_to_type(const Variant &p_val, const TypeInterface &p_arg_type);
 
 	bool _populate_object_type_interfaces();
 	void _populate_builtin_type_interfaces();