Core: Fix `Callable.get_bound_arguments{,_count}()` return incorrect data

9 files changed, 150 insertions, 63 deletions

diff --git a/core/variant/callable.cpp b/core/variant/callable.cpp
index 5ce90cd8ff..ddeea27118 100644
--- a/core/variant/callable.cpp
+++ b/core/variant/callable.cpp
@@ -206,19 +206,17 @@ int Callable::get_bound_arguments_count() const {
 	}
 }
 
-void Callable::get_bound_arguments_ref(Vector<Variant> &r_arguments, int &r_argcount) const {
+void Callable::get_bound_arguments_ref(Vector<Variant> &r_arguments) const {
 	if (!is_null() && is_custom()) {
-		custom->get_bound_arguments(r_arguments, r_argcount);
+		custom->get_bound_arguments(r_arguments);
 	} else {
 		r_arguments.clear();
-		r_argcount = 0;
 	}
 }
 
 Array Callable::get_bound_arguments() const {
 	Vector<Variant> arr;
-	int ac;
-	get_bound_arguments_ref(arr, ac);
+	get_bound_arguments_ref(arr);
 	Array ret;
 	ret.resize(arr.size());
 	for (int i = 0; i < arr.size(); i++) {
@@ -227,6 +225,14 @@ Array Callable::get_bound_arguments() const {
 	return ret;
 }
 
+int Callable::get_unbound_arguments_count() const {
+	if (!is_null() && is_custom()) {
+		return custom->get_unbound_arguments_count();
+	} else {
+		return 0;
+	}
+}
+
 CallableCustom *Callable::get_custom() const {
 	ERR_FAIL_COND_V_MSG(!is_custom(), nullptr,
 			vformat("Can't get custom on non-CallableCustom \"%s\".", operator String()));
@@ -464,9 +470,12 @@ int CallableCustom::get_bound_arguments_count() const {
 	return 0;
 }
 
-void CallableCustom::get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const {
-	r_arguments = Vector<Variant>();
-	r_argcount = 0;
+void CallableCustom::get_bound_arguments(Vector<Variant> &r_arguments) const {
+	r_arguments.clear();
+}
+
+int CallableCustom::get_unbound_arguments_count() const {
+	return 0;
 }
 
 CallableCustom::CallableCustom() {
diff --git a/core/variant/callable.h b/core/variant/callable.h
index e3c940a0e5..e76b888ac2 100644
--- a/core/variant/callable.h
+++ b/core/variant/callable.h
@@ -111,8 +111,9 @@ public:
 	CallableCustom *get_custom() const;
 	int get_argument_count(bool *r_is_valid = nullptr) const;
 	int get_bound_arguments_count() const;
-	void get_bound_arguments_ref(Vector<Variant> &r_arguments, int &r_argcount) const; // Internal engine use, the exposed one is below.
+	void get_bound_arguments_ref(Vector<Variant> &r_arguments) const; // Internal engine use, the exposed one is below.
 	Array get_bound_arguments() const;
+	int get_unbound_arguments_count() const;
 
 	uint32_t hash() const;
 
@@ -158,7 +159,8 @@ public:
 	virtual const Callable *get_base_comparator() const;
 	virtual int get_argument_count(bool &r_is_valid) const;
 	virtual int get_bound_arguments_count() const;
-	virtual void get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const;
+	virtual void get_bound_arguments(Vector<Variant> &r_arguments) const;
+	virtual int get_unbound_arguments_count() const;
 
 	CallableCustom();
 	virtual ~CallableCustom() {}
diff --git a/core/variant/callable_bind.cpp b/core/variant/callable_bind.cpp
index d82aa3583d..0bba329d7c 100644
--- a/core/variant/callable_bind.cpp
+++ b/core/variant/callable_bind.cpp
@@ -100,44 +100,42 @@ int CallableCustomBind::get_argument_count(bool &r_is_valid) const {
 }
 
 int CallableCustomBind::get_bound_arguments_count() const {
-	return callable.get_bound_arguments_count() + binds.size();
+	return callable.get_bound_arguments_count() + MAX(0, binds.size() - callable.get_unbound_arguments_count());
 }
 
-void CallableCustomBind::get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const {
-	Vector<Variant> sub_args;
-	int sub_count;
-	callable.get_bound_arguments_ref(sub_args, sub_count);
+void CallableCustomBind::get_bound_arguments(Vector<Variant> &r_arguments) const {
+	Vector<Variant> sub_bound_args;
+	callable.get_bound_arguments_ref(sub_bound_args);
+	int sub_bound_count = sub_bound_args.size();
 
-	if (sub_count == 0) {
+	int sub_unbound_count = callable.get_unbound_arguments_count();
+
+	if (sub_bound_count == 0 && sub_unbound_count == 0) {
 		r_arguments = binds;
-		r_argcount = binds.size();
 		return;
 	}
 
-	int new_count = sub_count + binds.size();
-	r_argcount = new_count;
+	int added_count = MAX(0, binds.size() - sub_unbound_count);
+	int new_count = sub_bound_count + added_count;
 
-	if (new_count <= 0) {
-		// Removed more arguments than it adds.
-		r_arguments = Vector<Variant>();
+	if (added_count <= 0) {
+		// All added arguments are consumed by `sub_unbound_count`.
+		r_arguments = sub_bound_args;
 		return;
 	}
 
 	r_arguments.resize(new_count);
-
-	if (sub_count > 0) {
-		for (int i = 0; i < sub_count; i++) {
-			r_arguments.write[i] = sub_args[i];
-		}
-		for (int i = 0; i < binds.size(); i++) {
-			r_arguments.write[i + sub_count] = binds[i];
-		}
-		r_argcount = new_count;
-	} else {
-		for (int i = 0; i < binds.size() + sub_count; i++) {
-			r_arguments.write[i] = binds[i - sub_count];
-		}
+	Variant *args = r_arguments.ptrw();
+	for (int i = 0; i < added_count; i++) {
+		args[i] = binds[i];
 	}
+	for (int i = 0; i < sub_bound_count; i++) {
+		args[i + added_count] = sub_bound_args[i];
+	}
+}
+
+int CallableCustomBind::get_unbound_arguments_count() const {
+	return MAX(0, callable.get_unbound_arguments_count() - binds.size());
 }
 
 void CallableCustomBind::call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const {
@@ -242,22 +240,15 @@ int CallableCustomUnbind::get_argument_count(bool &r_is_valid) const {
 }
 
 int CallableCustomUnbind::get_bound_arguments_count() const {
-	return callable.get_bound_arguments_count() - argcount;
+	return callable.get_bound_arguments_count();
 }
 
-void CallableCustomUnbind::get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const {
-	Vector<Variant> sub_args;
-	int sub_count;
-	callable.get_bound_arguments_ref(sub_args, sub_count);
-
-	r_argcount = sub_args.size() - argcount;
+void CallableCustomUnbind::get_bound_arguments(Vector<Variant> &r_arguments) const {
+	callable.get_bound_arguments_ref(r_arguments);
+}
 
-	if (argcount >= sub_args.size()) {
-		r_arguments = Vector<Variant>();
-	} else {
-		sub_args.resize(sub_args.size() - argcount);
-		r_arguments = sub_args;
-	}
+int CallableCustomUnbind::get_unbound_arguments_count() const {
+	return callable.get_unbound_arguments_count() + argcount;
 }
 
 void CallableCustomUnbind::call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const {
diff --git a/core/variant/callable_bind.h b/core/variant/callable_bind.h
index 43cebb45f0..1346277197 100644
--- a/core/variant/callable_bind.h
+++ b/core/variant/callable_bind.h
@@ -55,7 +55,8 @@ public:
 	virtual const Callable *get_base_comparator() const override;
 	virtual int get_argument_count(bool &r_is_valid) const override;
 	virtual int get_bound_arguments_count() const override;
-	virtual void get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const override;
+	virtual void get_bound_arguments(Vector<Variant> &r_arguments) const override;
+	virtual int get_unbound_arguments_count() const override;
 	Callable get_callable() { return callable; }
 	Vector<Variant> get_binds() { return binds; }
 
@@ -84,7 +85,8 @@ public:
 	virtual const Callable *get_base_comparator() const override;
 	virtual int get_argument_count(bool &r_is_valid) const override;
 	virtual int get_bound_arguments_count() const override;
-	virtual void get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const override;
+	virtual void get_bound_arguments(Vector<Variant> &r_arguments) const override;
+	virtual int get_unbound_arguments_count() const override;
 
 	Callable get_callable() { return callable; }
 	int get_unbinds() { return argcount; }
diff --git a/core/variant/variant.cpp b/core/variant/variant.cpp
index 7550477d70..9b317d449e 100644
--- a/core/variant/variant.cpp
+++ b/core/variant/variant.cpp
@@ -3668,18 +3668,20 @@ String Variant::get_call_error_text(Object *p_base, const StringName &p_method,
 
 String Variant::get_callable_error_text(const Callable &p_callable, const Variant **p_argptrs, int p_argcount, const Callable::CallError &ce) {
 	Vector<Variant> binds;
-	int args_bound;
-	p_callable.get_bound_arguments_ref(binds, args_bound);
-	if (args_bound <= 0) {
-		return get_call_error_text(p_callable.get_object(), p_callable.get_method(), p_argptrs, MAX(0, p_argcount + args_bound), ce);
+	p_callable.get_bound_arguments_ref(binds);
+
+	int args_unbound = p_callable.get_unbound_arguments_count();
+
+	if (p_argcount - args_unbound < 0) {
+		return "Callable unbinds " + itos(args_unbound) + " arguments, but called with " + itos(p_argcount);
 	} else {
 		Vector<const Variant *> argptrs;
-		argptrs.resize(p_argcount + binds.size());
-		for (int i = 0; i < p_argcount; i++) {
+		argptrs.resize(p_argcount - args_unbound + binds.size());
+		for (int i = 0; i < p_argcount - args_unbound; i++) {
 			argptrs.write[i] = p_argptrs[i];
 		}
 		for (int i = 0; i < binds.size(); i++) {
-			argptrs.write[i + p_argcount] = &binds[i];
+			argptrs.write[i + p_argcount - args_unbound] = &binds[i];
 		}
 		return get_call_error_text(p_callable.get_object(), p_callable.get_method(), (const Variant **)argptrs.ptr(), argptrs.size(), ce);
 	}
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 29e11462c9..381b848b2b 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -2116,6 +2116,7 @@ static void _register_variant_builtin_methods_misc() {
 	bind_function(Callable, get_argument_count, _VariantCall::func_Callable_get_argument_count, sarray(), varray());
 	bind_method(Callable, get_bound_arguments_count, sarray(), varray());
 	bind_method(Callable, get_bound_arguments, sarray(), varray());
+	bind_method(Callable, get_unbound_arguments_count, sarray(), varray());
 	bind_method(Callable, hash, sarray(), varray());
 	bind_method(Callable, bindv, sarray("arguments"), varray());
 	bind_method(Callable, unbind, sarray("argcount"), varray());
diff --git a/doc/classes/Callable.xml b/doc/classes/Callable.xml
index 0c8f3c66f5..cf3c3e06fd 100644
--- a/doc/classes/Callable.xml
+++ b/doc/classes/Callable.xml
@@ -155,13 +155,21 @@
 		<method name="get_bound_arguments" qualifiers="const">
 			<return type="Array" />
 			<description>
-				Return the bound arguments (as long as [method get_bound_arguments_count] is greater than zero), or empty (if [method get_bound_arguments_count] is less than or equal to zero).
+				Returns the array of arguments bound via successive [method bind] or [method unbind] calls. These arguments will be added [i]after[/i] the arguments passed to the call, from which [method get_unbound_arguments_count] arguments on the right have been previously excluded.
+				[codeblock]
+				func get_effective_arguments(callable, call_args):
+				    assert(call_args.size() - callable.get_unbound_arguments_count() &gt;= 0)
+				    var result = call_args.slice(0, call_args.size() - callable.get_unbound_arguments_count())
+				    result.append_array(callable.get_bound_arguments())
+				    return result
+				[/codeblock]
 			</description>
 		</method>
 		<method name="get_bound_arguments_count" qualifiers="const">
 			<return type="int" />
 			<description>
-				Returns the total amount of arguments bound (or unbound) via successive [method bind] or [method unbind] calls. If the amount of arguments unbound is greater than the ones bound, this function returns a value less than zero.
+				Returns the total amount of arguments bound via successive [method bind] or [method unbind] calls. This is the same as the size of the array returned by [method get_bound_arguments]. See [method get_bound_arguments] for details.
+				[b]Note:[/b] The [method get_bound_arguments_count] and [method get_unbound_arguments_count] methods can both return positive values.
 			</description>
 		</method>
 		<method name="get_method" qualifiers="const">
@@ -182,6 +190,13 @@
 				Returns the ID of this [Callable]'s object (see [method Object.get_instance_id]).
 			</description>
 		</method>
+		<method name="get_unbound_arguments_count" qualifiers="const">
+			<return type="int" />
+			<description>
+				Returns the total amount of arguments unbound via successive [method bind] or [method unbind] calls. See [method get_bound_arguments] for details.
+				[b]Note:[/b] The [method get_bound_arguments_count] and [method get_unbound_arguments_count] methods can both return positive values.
+			</description>
+		</method>
 		<method name="hash" qualifiers="const">
 			<return type="int" />
 			<description>
diff --git a/scene/main/node.cpp b/scene/main/node.cpp
index 8dc7b4a87c..5063f0d6d0 100644
--- a/scene/main/node.cpp
+++ b/scene/main/node.cpp
@@ -3055,11 +3055,12 @@ void Node::_duplicate_signals(const Node *p_original, Node *p_copy) const {
 				if (copy && copytarget && E.callable.get_method() != StringName()) {
 					Callable copy_callable = Callable(copytarget, E.callable.get_method());
 					if (!copy->is_connected(E.signal.get_name(), copy_callable)) {
-						int arg_count = E.callable.get_bound_arguments_count();
-						if (arg_count > 0) {
+						int unbound_arg_count = E.callable.get_unbound_arguments_count();
+						if (unbound_arg_count > 0) {
+							copy_callable = copy_callable.unbind(unbound_arg_count);
+						}
+						if (E.callable.get_bound_arguments_count() > 0) {
 							copy_callable = copy_callable.bindv(E.callable.get_bound_arguments());
-						} else if (arg_count < 0) {
-							copy_callable = copy_callable.unbind(-arg_count);
 						}
 						copy->connect(E.signal.get_name(), copy_callable, E.flags);
 					}
diff --git a/tests/core/variant/test_callable.h b/tests/core/variant/test_callable.h
index 3228e0a583..34ea8fad5c 100644
--- a/tests/core/variant/test_callable.h
+++ b/tests/core/variant/test_callable.h
@@ -135,6 +135,70 @@ TEST_CASE("[Callable] Argument count") {
 
 	memdelete(my_test);
 }
+
+class TestBoundUnboundArgumentCount : public Object {
+	GDCLASS(TestBoundUnboundArgumentCount, Object);
+
+protected:
+	static void _bind_methods() {
+		ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "test_func", &TestBoundUnboundArgumentCount::test_func, MethodInfo("test_func"));
+	}
+
+public:
+	Variant test_func(const Variant **p_args, int p_argcount, Callable::CallError &r_error) {
+		Array result;
+		result.resize(p_argcount);
+		for (int i = 0; i < p_argcount; i++) {
+			result[i] = *p_args[i];
+		}
+		return result;
+	}
+
+	static String get_output(const Callable &p_callable) {
+		Array effective_args;
+		effective_args.push_back(7);
+		effective_args.push_back(8);
+		effective_args.push_back(9);
+
+		effective_args.resize(3 - p_callable.get_unbound_arguments_count());
+		effective_args.append_array(p_callable.get_bound_arguments());
+
+		return vformat(
+				"%d %d %s %s %s",
+				p_callable.get_unbound_arguments_count(),
+				p_callable.get_bound_arguments_count(),
+				p_callable.get_bound_arguments(),
+				p_callable.call(7, 8, 9),
+				effective_args);
+	}
+};
+
+TEST_CASE("[Callable] Bound and unbound argument count") {
+	String (*get_output)(const Callable &) = TestBoundUnboundArgumentCount::get_output;
+
+	TestBoundUnboundArgumentCount *test_instance = memnew(TestBoundUnboundArgumentCount);
+
+	Callable test_func = Callable(test_instance, "test_func");
+
+	CHECK(get_output(test_func) == "0 0 [] [7, 8, 9] [7, 8, 9]");
+	CHECK(get_output(test_func.bind(1, 2)) == "0 2 [1, 2] [7, 8, 9, 1, 2] [7, 8, 9, 1, 2]");
+	CHECK(get_output(test_func.bind(1, 2).unbind(1)) == "1 2 [1, 2] [7, 8, 1, 2] [7, 8, 1, 2]");
+	CHECK(get_output(test_func.bind(1, 2).unbind(1).bind(3, 4)) == "0 3 [3, 1, 2] [7, 8, 9, 3, 1, 2] [7, 8, 9, 3, 1, 2]");
+	CHECK(get_output(test_func.bind(1, 2).unbind(1).bind(3, 4).unbind(1)) == "1 3 [3, 1, 2] [7, 8, 3, 1, 2] [7, 8, 3, 1, 2]");
+
+	CHECK(get_output(test_func.bind(1).bind(2).bind(3).unbind(1)) == "1 3 [3, 2, 1] [7, 8, 3, 2, 1] [7, 8, 3, 2, 1]");
+	CHECK(get_output(test_func.bind(1).bind(2).unbind(1).bind(3)) == "0 2 [2, 1] [7, 8, 9, 2, 1] [7, 8, 9, 2, 1]");
+	CHECK(get_output(test_func.bind(1).unbind(1).bind(2).bind(3)) == "0 2 [3, 1] [7, 8, 9, 3, 1] [7, 8, 9, 3, 1]");
+	CHECK(get_output(test_func.unbind(1).bind(1).bind(2).bind(3)) == "0 2 [3, 2] [7, 8, 9, 3, 2] [7, 8, 9, 3, 2]");
+
+	CHECK(get_output(test_func.unbind(1).unbind(1).unbind(1).bind(1, 2, 3)) == "0 0 [] [7, 8, 9] [7, 8, 9]");
+	CHECK(get_output(test_func.unbind(1).unbind(1).bind(1, 2, 3).unbind(1)) == "1 1 [1] [7, 8, 1] [7, 8, 1]");
+	CHECK(get_output(test_func.unbind(1).bind(1, 2, 3).unbind(1).unbind(1)) == "2 2 [1, 2] [7, 1, 2] [7, 1, 2]");
+	CHECK(get_output(test_func.bind(1, 2, 3).unbind(1).unbind(1).unbind(1)) == "3 3 [1, 2, 3] [1, 2, 3] [1, 2, 3]");
+
+	memdelete(test_instance);
+}
+
 } // namespace TestCallable
 
 #endif // TEST_CALLABLE_H