Fix unsafe uses of `Callable.is_null()`

`Callable.is_null()` is not equivalent to `!Callable.is_valid()` and
doesn't guarantee the call is valid.

core/core_bind.cpp

@@ -1921,7 +1921,7 @@ void EngineDebugger::send_message(const String &p_msg, const Array &p_data) {
 
 Error EngineDebugger::call_capture(void *p_user, const String &p_cmd, const Array &p_data, bool &r_captured) {
 	Callable &capture = *(Callable *)p_user;
-	if (capture.is_null()) {
+	if (!capture.is_valid()) {
 		return FAILED;
 	}
 	Variant cmd = p_cmd, data = p_data;

core/object/object.cpp

@@ -1455,7 +1455,7 @@ Error Object::connect(const StringName &p_signal, const Callable &p_callable, ui
 }
 
 bool Object::is_connected(const StringName &p_signal, const Callable &p_callable) const {
-	ERR_FAIL_COND_V_MSG(p_callable.is_null(), false, "Cannot determine if connected to '" + p_signal + "': the provided callable is null.");
+	ERR_FAIL_COND_V_MSG(p_callable.is_null(), false, "Cannot determine if connected to '" + p_signal + "': the provided callable is null."); // Should use `is_null`, see note in `connect` about the use of `is_valid`.
 	const SignalData *s = signal_map.getptr(p_signal);
 	if (!s) {
 		bool signal_is_valid = ClassDB::has_signal(get_class_name(), p_signal);
@@ -1478,7 +1478,7 @@ void Object::disconnect(const StringName &p_signal, const Callable &p_callable)
 }
 
 bool Object::_disconnect(const StringName &p_signal, const Callable &p_callable, bool p_force) {
-	ERR_FAIL_COND_V_MSG(p_callable.is_null(), false, "Cannot disconnect from '" + p_signal + "': the provided callable is null.");
+	ERR_FAIL_COND_V_MSG(p_callable.is_null(), false, "Cannot disconnect from '" + p_signal + "': the provided callable is null."); // Should use `is_null`, see note in `connect` about the use of `is_valid`.
 
 	SignalData *s = signal_map.getptr(p_signal);
 	if (!s) {

core/object/undo_redo.cpp

@@ -144,7 +144,7 @@ void UndoRedo::create_action(const String &p_name, MergeMode p_mode, bool p_back
 }
 
 void UndoRedo::add_do_method(const Callable &p_callable) {
-	ERR_FAIL_COND(p_callable.is_null());
+	ERR_FAIL_COND(!p_callable.is_valid());
 	ERR_FAIL_COND(action_level <= 0);
 	ERR_FAIL_COND((current_action + 1) >= actions.size());
 
@@ -169,7 +169,7 @@ void UndoRedo::add_do_method(const Callable &p_callable) {
 }
 
 void UndoRedo::add_undo_method(const Callable &p_callable) {
-	ERR_FAIL_COND(p_callable.is_null());
+	ERR_FAIL_COND(!p_callable.is_valid());
 	ERR_FAIL_COND(action_level <= 0);
 	ERR_FAIL_COND((current_action + 1) >= actions.size());
 

drivers/gles3/storage/utilities.cpp

@@ -299,7 +299,7 @@ void Utilities::visibility_notifier_call(RID p_notifier, bool p_enter, bool p_de
 	ERR_FAIL_NULL(vn);
 
 	if (p_enter) {
-		if (!vn->enter_callback.is_null()) {
+		if (vn->enter_callback.is_valid()) {
 			if (p_deferred) {
 				vn->enter_callback.call_deferred();
 			} else {
@@ -307,7 +307,7 @@ void Utilities::visibility_notifier_call(RID p_notifier, bool p_enter, bool p_de
 			}
 		}
 	} else {
-		if (!vn->exit_callback.is_null()) {
+		if (vn->exit_callback.is_valid()) {
 			if (p_deferred) {
 				vn->exit_callback.call_deferred();
 			} else {

editor/gui/editor_validation_panel.cpp

@@ -81,7 +81,7 @@ void EditorValidationPanel::set_update_callback(const Callable &p_callback) {
 }
 
 void EditorValidationPanel::update() {
-	ERR_FAIL_COND(update_callback.is_null());
+	ERR_FAIL_COND(!update_callback.is_valid());
 
 	if (pending_update) {
 		return;

platform/android/display_server_android.cpp

@@ -326,7 +326,7 @@ void DisplayServerAndroid::window_set_drop_files_callback(const Callable &p_call
 }
 
 void DisplayServerAndroid::_window_callback(const Callable &p_callable, const Variant &p_arg, bool p_deferred) const {
-	if (!p_callable.is_null()) {
+	if (p_callable.is_valid()) {
 		if (p_deferred) {
 			p_callable.call_deferred(p_arg);
 		} else {

platform/ios/display_server_ios.mm

@@ -218,7 +218,7 @@ void DisplayServerIOS::send_window_event(DisplayServer::WindowEvent p_event) con
 }
 
 void DisplayServerIOS::_window_callback(const Callable &p_callable, const Variant &p_arg) const {
-	if (!p_callable.is_null()) {
+	if (p_callable.is_valid()) {
 		p_callable.call(p_arg);
 	}
 }

platform/linuxbsd/x11/display_server_x11.cpp

@@ -4992,7 +4992,7 @@ void DisplayServerX11::process_events() {
 						files.write[i] = files[i].replace("file://", "").uri_decode();
 					}
 
-					if (!windows[window_id].drop_files_callback.is_null()) {
+					if (windows[window_id].drop_files_callback.is_valid()) {
 						windows[window_id].drop_files_callback.call(files);
 					}
 

platform/macos/display_server_macos.mm

@@ -938,7 +938,7 @@ Error DisplayServerMacOS::dialog_show(String p_title, String p_description, Vect
 		button_pressed = int64_t(2 + (ret - NSAlertThirdButtonReturn));
 	}
 
-	if (!p_callback.is_null()) {
+	if (p_callback.is_valid()) {
 		Variant ret;
 		Callable::CallError ce;
 		const Variant *args[1] = { &button_pressed };
@@ -1018,7 +1018,7 @@ Error DisplayServerMacOS::_file_dialog_with_options_show(const String &p_title,
 							  String url;
 							  url.parse_utf8([[[panel URL] path] UTF8String]);
 							  files.push_back(url);
-							  if (!callback.is_null()) {
+							  if (callback.is_valid()) {
 								  if (p_options_in_cb) {
 									  Variant v_result = true;
 									  Variant v_files = files;
@@ -1047,7 +1047,7 @@ Error DisplayServerMacOS::_file_dialog_with_options_show(const String &p_title,
 								  }
 							  }
 						  } else {
-							  if (!callback.is_null()) {
+							  if (callback.is_valid()) {
 								  if (p_options_in_cb) {
 									  Variant v_result = false;
 									  Variant v_files = Vector<String>();
@@ -1134,7 +1134,7 @@ Error DisplayServerMacOS::_file_dialog_with_options_show(const String &p_title,
 								  url.parse_utf8([[[urls objectAtIndex:i] path] UTF8String]);
 								  files.push_back(url);
 							  }
-							  if (!callback.is_null()) {
+							  if (callback.is_valid()) {
 								  if (p_options_in_cb) {
 									  Variant v_result = true;
 									  Variant v_files = files;
@@ -1163,7 +1163,7 @@ Error DisplayServerMacOS::_file_dialog_with_options_show(const String &p_title,
 								  }
 							  }
 						  } else {
-							  if (!callback.is_null()) {
+							  if (callback.is_valid()) {
 								  if (p_options_in_cb) {
 									  Variant v_result = false;
 									  Variant v_files = Vector<String>();
@@ -1222,7 +1222,7 @@ Error DisplayServerMacOS::dialog_input_text(String p_title, String p_description
 	String ret;
 	ret.parse_utf8([[input stringValue] UTF8String]);
 
-	if (!p_callback.is_null()) {
+	if (p_callback.is_valid()) {
 		Variant v_result = ret;
 		Variant ret;
 		Callable::CallError ce;

platform/macos/godot_content_view.mm

@@ -313,7 +313,7 @@
 	}
 
 	DisplayServerMacOS::WindowData &wd = ds->get_window(window_id);
-	if (!wd.drop_files_callback.is_null()) {
+	if (wd.drop_files_callback.is_valid()) {
 		Vector<String> files;
 		NSPasteboard *pboard = [sender draggingPasteboard];
 

platform/macos/godot_window_delegate.mm

@@ -268,7 +268,7 @@
 
 	ds->window_resize(window_id, wd.size.width, wd.size.height);
 
-	if (!wd.rect_changed_callback.is_null()) {
+	if (wd.rect_changed_callback.is_valid()) {
 		wd.rect_changed_callback.call(Rect2i(ds->window_get_position(window_id), ds->window_get_size(window_id)));
 	}
 }
@@ -291,7 +291,7 @@
 	DisplayServerMacOS::WindowData &wd = ds->get_window(window_id);
 	ds->release_pressed_events();
 
-	if (!wd.rect_changed_callback.is_null()) {
+	if (wd.rect_changed_callback.is_valid()) {
 		wd.rect_changed_callback.call(Rect2i(ds->window_get_position(window_id), ds->window_get_size(window_id)));
 	}
 }

platform/web/display_server_web.cpp

@@ -58,7 +58,7 @@ DisplayServerWeb *DisplayServerWeb::get_singleton() {
 // Window (canvas)
 bool DisplayServerWeb::check_size_force_redraw() {
 	bool size_changed = godot_js_display_size_update() != 0;
-	if (size_changed && !rect_changed_callback.is_null()) {
+	if (size_changed && rect_changed_callback.is_valid()) {
 		Size2i window_size = window_get_size();
 		Variant size = Rect2i(Point2i(), window_size); // TODO use window_get_position if implemented.
 		rect_changed_callback.call(size);
@@ -109,7 +109,7 @@ void DisplayServerWeb::_drop_files_js_callback(const Vector<String> &p_files) {
 	if (!ds) {
 		ERR_FAIL_MSG("Unable to drop files because the DisplayServer is not active");
 	}
-	if (ds->drop_files_callback.is_null()) {
+	if (!ds->drop_files_callback.is_valid()) {
 		return;
 	}
 	ds->drop_files_callback.call(p_files);
@@ -129,7 +129,7 @@ void DisplayServerWeb::request_quit_callback() {
 
 void DisplayServerWeb::_request_quit_callback() {
 	DisplayServerWeb *ds = get_singleton();
-	if (ds && !ds->window_event_callback.is_null()) {
+	if (ds && ds->window_event_callback.is_valid()) {
 		Variant event = int(DisplayServer::WINDOW_EVENT_CLOSE_REQUEST);
 		ds->window_event_callback.call(event);
 	}
@@ -722,7 +722,7 @@ void DisplayServerWeb::vk_input_text_callback(const char *p_text, int p_cursor)
 
 void DisplayServerWeb::_vk_input_text_callback(const String &p_text, int p_cursor) {
 	DisplayServerWeb *ds = DisplayServerWeb::get_singleton();
-	if (!ds || ds->input_text_callback.is_null()) {
+	if (!ds || !ds->input_text_callback.is_valid()) {
 		return;
 	}
 	// Call input_text
@@ -972,7 +972,7 @@ void DisplayServerWeb::_send_window_event_callback(int p_notification) {
 	if (godot_js_is_ime_focused() && (p_notification == DisplayServer::WINDOW_EVENT_FOCUS_IN || p_notification == DisplayServer::WINDOW_EVENT_FOCUS_OUT)) {
 		return;
 	}
-	if (!ds->window_event_callback.is_null()) {
+	if (ds->window_event_callback.is_valid()) {
 		Variant event = int(p_notification);
 		ds->window_event_callback.call(event);
 	}

platform/web/javascript_bridge_singleton.cpp

@@ -248,7 +248,7 @@ Variant JavaScriptObjectImpl::callp(const StringName &p_method, const Variant **
 
 void JavaScriptObjectImpl::callback(void *p_ref, int p_args_id, int p_argc) {
 	const JavaScriptObjectImpl *obj = (JavaScriptObjectImpl *)p_ref;
-	ERR_FAIL_COND_MSG(obj->_callable.is_null(), "JavaScript callback failed.");
+	ERR_FAIL_COND_MSG(!obj->_callable.is_valid(), "JavaScript callback failed.");
 
 	Vector<const Variant *> argp;
 	Array arg_arr;

platform/windows/display_server_windows.cpp

@@ -545,7 +545,7 @@ Error DisplayServerWindows::_file_dialog_with_options_show(const String &p_title
 					result->Release();
 				}
 			}
-			if (!p_callback.is_null()) {
+			if (p_callback.is_valid()) {
 				if (p_options_in_cb) {
 					Variant v_result = true;
 					Variant v_files = file_names;
@@ -574,7 +574,7 @@ Error DisplayServerWindows::_file_dialog_with_options_show(const String &p_title
 				}
 			}
 		} else {
-			if (!p_callback.is_null()) {
+			if (p_callback.is_valid()) {
 				if (p_options_in_cb) {
 					Variant v_result = false;
 					Variant v_files = Vector<String>();
@@ -2556,7 +2556,7 @@ Error DisplayServerWindows::dialog_show(String p_title, String p_description, Ve
 		int button_pressed;
 
 		if (task_dialog_indirect && SUCCEEDED(task_dialog_indirect(&config, &button_pressed, nullptr, nullptr))) {
-			if (!p_callback.is_null()) {
+			if (p_callback.is_valid()) {
 				Variant button = button_pressed;
 				const Variant *args[1] = { &button };
 				Variant ret;
@@ -4591,7 +4591,7 @@ LRESULT DisplayServerWindows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARA
 			}
 
 			if (rect_changed) {
-				if (!window.rect_changed_callback.is_null()) {
+				if (window.rect_changed_callback.is_valid()) {
 					window.rect_changed_callback.call(Rect2i(window.last_pos.x, window.last_pos.y, window.width, window.height));
 				}
 
@@ -4803,7 +4803,7 @@ LRESULT DisplayServerWindows::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARA
 				files.push_back(file);
 			}
 
-			if (files.size() && !windows[window_id].drop_files_callback.is_null()) {
+			if (files.size() && windows[window_id].drop_files_callback.is_valid()) {
 				windows[window_id].drop_files_callback.call(files);
 			}
 		} break;

servers/physics_2d/godot_area_2d.h

@@ -101,10 +101,10 @@ class GodotArea2D : public GodotCollisionObject2D {
 
 public:
 	void set_monitor_callback(const Callable &p_callback);
-	_FORCE_INLINE_ bool has_monitor_callback() const { return !monitor_callback.is_null(); }
+	_FORCE_INLINE_ bool has_monitor_callback() const { return monitor_callback.is_valid(); }
 
 	void set_area_monitor_callback(const Callable &p_callback);
-	_FORCE_INLINE_ bool has_area_monitor_callback() const { return !area_monitor_callback.is_null(); }
+	_FORCE_INLINE_ bool has_area_monitor_callback() const { return area_monitor_callback.is_valid(); }
 
 	_FORCE_INLINE_ void add_body_to_query(GodotBody2D *p_body, uint32_t p_body_shape, uint32_t p_area_shape);
 	_FORCE_INLINE_ void remove_body_from_query(GodotBody2D *p_body, uint32_t p_body_shape, uint32_t p_area_shape);

servers/physics_3d/godot_area_3d.h

@@ -107,10 +107,10 @@ class GodotArea3D : public GodotCollisionObject3D {
 
 public:
 	void set_monitor_callback(const Callable &p_callback);
-	_FORCE_INLINE_ bool has_monitor_callback() const { return !monitor_callback.is_null(); }
+	_FORCE_INLINE_ bool has_monitor_callback() const { return monitor_callback.is_valid(); }
 
 	void set_area_monitor_callback(const Callable &p_callback);
-	_FORCE_INLINE_ bool has_area_monitor_callback() const { return !area_monitor_callback.is_null(); }
+	_FORCE_INLINE_ bool has_area_monitor_callback() const { return area_monitor_callback.is_valid(); }
 
 	_FORCE_INLINE_ void add_body_to_query(GodotBody3D *p_body, uint32_t p_body_shape, uint32_t p_area_shape);
 	_FORCE_INLINE_ void remove_body_from_query(GodotBody3D *p_body, uint32_t p_body_shape, uint32_t p_area_shape);

servers/rendering/renderer_canvas_cull.cpp

@@ -2106,7 +2106,7 @@ void RendererCanvasCull::update_visibility_notifiers() {
 		if (visibility_notifier->just_visible) {
 			visibility_notifier->just_visible = false;
 
-			if (!visibility_notifier->enter_callable.is_null()) {
+			if (visibility_notifier->enter_callable.is_valid()) {
 				if (RSG::threaded) {
 					visibility_notifier->enter_callable.call_deferred();
 				} else {
@@ -2117,7 +2117,7 @@ void RendererCanvasCull::update_visibility_notifiers() {
 			if (visibility_notifier->visible_in_frame != RSG::rasterizer->get_frame_number()) {
 				visibility_notifier_list.remove(E);
 
-				if (!visibility_notifier->exit_callable.is_null()) {
+				if (visibility_notifier->exit_callable.is_valid()) {
 					if (RSG::threaded) {
 						visibility_notifier->exit_callable.call_deferred();
 					} else {

servers/rendering/renderer_rd/storage_rd/utilities.cpp

@@ -198,7 +198,7 @@ void Utilities::visibility_notifier_call(RID p_notifier, bool p_enter, bool p_de
 	ERR_FAIL_NULL(vn);
 
 	if (p_enter) {
-		if (!vn->enter_callback.is_null()) {
+		if (vn->enter_callback.is_valid()) {
 			if (p_deferred) {
 				vn->enter_callback.call_deferred();
 			} else {
@@ -206,7 +206,7 @@ void Utilities::visibility_notifier_call(RID p_notifier, bool p_enter, bool p_de
 			}
 		}
 	} else {
-		if (!vn->exit_callback.is_null()) {
+		if (vn->exit_callback.is_valid()) {
 			if (p_deferred) {
 				vn->exit_callback.call_deferred();
 			} else {

tests/display_server_mock.h

@@ -86,7 +86,7 @@ private:
 	}
 
 	void _send_window_event(WindowEvent p_event) {
-		if (!event_callback.is_null()) {
+		if (event_callback.is_valid()) {
 			Variant event = int(p_event);
 			event_callback.call(event);
 		}