Add methods to get argument count of methods

Added to:
* `Callable`s
* `Object`s
* `ClassDB`
* `Script(Instance)`s

2 files changed, 146 insertions, 0 deletions

diff --git a/tests/core/object/test_object.h b/tests/core/object/test_object.h
index e5d91db650..3a3013a102 100644
--- a/tests/core/object/test_object.h
+++ b/tests/core/object/test_object.h
@@ -95,6 +95,12 @@ public:
 	bool has_method(const StringName &p_method) const override {
 		return false;
 	}
+	int get_method_argument_count(const StringName &p_method, bool *r_is_valid = nullptr) const override {
+		if (r_is_valid) {
+			*r_is_valid = false;
+		}
+		return 0;
+	}
 	Variant callp(const StringName &p_method, const Variant **p_args, int p_argcount, Callable::CallError &r_error) override {
 		return Variant();
 	}
diff --git a/tests/core/variant/test_callable.h b/tests/core/variant/test_callable.h
new file mode 100644
index 0000000000..3228e0a583
--- /dev/null
+++ b/tests/core/variant/test_callable.h
@@ -0,0 +1,140 @@
+/**************************************************************************/
+/*  test_callable.h                                                       */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* 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 TEST_CALLABLE_H
+#define TEST_CALLABLE_H
+
+#include "core/object/class_db.h"
+#include "core/object/object.h"
+
+#include "tests/test_macros.h"
+
+namespace TestCallable {
+
+class TestClass : public Object {
+	GDCLASS(TestClass, Object);
+
+protected:
+	static void _bind_methods() {
+		ClassDB::bind_method(D_METHOD("test_func_1", "foo", "bar"), &TestClass::test_func_1);
+		ClassDB::bind_method(D_METHOD("test_func_2", "foo", "bar", "baz"), &TestClass::test_func_2);
+		ClassDB::bind_static_method("TestClass", D_METHOD("test_func_5", "foo", "bar"), &TestClass::test_func_5);
+		ClassDB::bind_static_method("TestClass", D_METHOD("test_func_6", "foo", "bar", "baz"), &TestClass::test_func_6);
+
+		{
+			MethodInfo mi;
+			mi.name = "test_func_7";
+			mi.arguments.push_back(PropertyInfo(Variant::INT, "foo"));
+			mi.arguments.push_back(PropertyInfo(Variant::INT, "bar"));
+
+			ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "test_func_7", &TestClass::test_func_7, mi, varray(), false);
+		}
+
+		{
+			MethodInfo mi;
+			mi.name = "test_func_8";
+			mi.arguments.push_back(PropertyInfo(Variant::INT, "foo"));
+			mi.arguments.push_back(PropertyInfo(Variant::INT, "bar"));
+			mi.arguments.push_back(PropertyInfo(Variant::INT, "baz"));
+
+			ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "test_func_8", &TestClass::test_func_8, mi, varray(), false);
+		}
+	}
+
+public:
+	void test_func_1(int p_foo, int p_bar) {}
+	void test_func_2(int p_foo, int p_bar, int p_baz) {}
+
+	int test_func_3(int p_foo, int p_bar) const { return 0; }
+	int test_func_4(int p_foo, int p_bar, int p_baz) const { return 0; }
+
+	static void test_func_5(int p_foo, int p_bar) {}
+	static void test_func_6(int p_foo, int p_bar, int p_baz) {}
+
+	void test_func_7(const Variant **p_args, int p_argcount, Callable::CallError &r_error) {}
+	void test_func_8(const Variant **p_args, int p_argcount, Callable::CallError &r_error) {}
+};
+
+TEST_CASE("[Callable] Argument count") {
+	TestClass *my_test = memnew(TestClass);
+
+	// Bound methods tests.
+
+	// Test simple methods.
+	Callable callable_1 = Callable(my_test, "test_func_1");
+	CHECK_EQ(callable_1.get_argument_count(), 2);
+	Callable callable_2 = Callable(my_test, "test_func_2");
+	CHECK_EQ(callable_2.get_argument_count(), 3);
+	Callable callable_3 = Callable(my_test, "test_func_5");
+	CHECK_EQ(callable_3.get_argument_count(), 2);
+	Callable callable_4 = Callable(my_test, "test_func_6");
+	CHECK_EQ(callable_4.get_argument_count(), 3);
+
+	// Test vararg methods.
+	Callable callable_vararg_1 = Callable(my_test, "test_func_7");
+	CHECK_MESSAGE(callable_vararg_1.get_argument_count() == 2, "vararg Callable should return the number of declared arguments");
+	Callable callable_vararg_2 = Callable(my_test, "test_func_8");
+	CHECK_MESSAGE(callable_vararg_2.get_argument_count() == 3, "vararg Callable should return the number of declared arguments");
+
+	// Callable MP tests.
+
+	// Test simple methods.
+	Callable callable_mp_1 = callable_mp(my_test, &TestClass::test_func_1);
+	CHECK_EQ(callable_mp_1.get_argument_count(), 2);
+	Callable callable_mp_2 = callable_mp(my_test, &TestClass::test_func_2);
+	CHECK_EQ(callable_mp_2.get_argument_count(), 3);
+	Callable callable_mp_3 = callable_mp(my_test, &TestClass::test_func_3);
+	CHECK_EQ(callable_mp_3.get_argument_count(), 2);
+	Callable callable_mp_4 = callable_mp(my_test, &TestClass::test_func_4);
+	CHECK_EQ(callable_mp_4.get_argument_count(), 3);
+
+	// Test static methods.
+	Callable callable_mp_static_1 = callable_mp_static(&TestClass::test_func_5);
+	CHECK_EQ(callable_mp_static_1.get_argument_count(), 2);
+	Callable callable_mp_static_2 = callable_mp_static(&TestClass::test_func_6);
+	CHECK_EQ(callable_mp_static_2.get_argument_count(), 3);
+
+	// Test bind.
+	Callable callable_mp_bind_1 = callable_mp_2.bind(1);
+	CHECK_MESSAGE(callable_mp_bind_1.get_argument_count() == 2, "bind should subtract from the argument count");
+	Callable callable_mp_bind_2 = callable_mp_2.bind(1, 2);
+	CHECK_MESSAGE(callable_mp_bind_2.get_argument_count() == 1, "bind should subtract from the argument count");
+
+	// Test unbind.
+	Callable callable_mp_unbind_1 = callable_mp_2.unbind(1);
+	CHECK_MESSAGE(callable_mp_unbind_1.get_argument_count() == 4, "unbind should add to the argument count");
+	Callable callable_mp_unbind_2 = callable_mp_2.unbind(2);
+	CHECK_MESSAGE(callable_mp_unbind_2.get_argument_count() == 5, "unbind should add to the argument count");
+
+	memdelete(my_test);
+}
+} // namespace TestCallable
+
+#endif // TEST_CALLABLE_H