Made serialization of Command toggleable when saving InputEvents.

Made serialization of Command optional. If command is serialized, Control (On Win/Linux) or Meta (on Mac) are not.
Example use case: You are on Windows and you set a shortcut to be Control + E. This would serialize as Command=true and Control=true. If you then run this project on Mac, you would need to press Command AND Control to activate the shortcut - which is not what is intended. Now, you can set store_command to true, and it will only serialize to Command = true (no Control serialized). On Windows, this means Control. On Mac, it means only command.

core/input/input_event.cpp

@@ -138,6 +138,14 @@ int64_t InputEventFromWindow::get_window_id() const {
 
 ///////////////////////////////////
 
+void InputEventWithModifiers::set_store_command(bool p_enabled) {
+	store_command = p_enabled;
+}
+
+bool InputEventWithModifiers::is_storing_command() const {
+	return store_command;
+}
+
 void InputEventWithModifiers::set_shift(bool p_enabled) {
 	shift = p_enabled;
 }
@@ -186,6 +194,9 @@ void InputEventWithModifiers::set_modifiers_from_event(const InputEventWithModif
 }
 
 void InputEventWithModifiers::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_store_command", "enable"), &InputEventWithModifiers::set_store_command);
+	ClassDB::bind_method(D_METHOD("is_storing_command"), &InputEventWithModifiers::is_storing_command);
+
 	ClassDB::bind_method(D_METHOD("set_alt", "enable"), &InputEventWithModifiers::set_alt);
 	ClassDB::bind_method(D_METHOD("get_alt"), &InputEventWithModifiers::get_alt);
 
@@ -201,13 +212,36 @@ void InputEventWithModifiers::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_command", "enable"), &InputEventWithModifiers::set_command);
 	ClassDB::bind_method(D_METHOD("get_command"), &InputEventWithModifiers::get_command);
 
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "store_command"), "set_store_command", "is_storing_command");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "alt"), "set_alt", "get_alt");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "shift"), "set_shift", "get_shift");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "control"), "set_control", "get_control");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "meta"), "set_metakey", "get_metakey");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "command"), "set_command", "get_command");
 }
 
+void InputEventWithModifiers::_validate_property(PropertyInfo &property) const {
+	if (store_command) {
+		// If we only want to Store "Command".
+#ifdef APPLE_STYLE_KEYS
+		// Don't store "Meta" on Mac.
+		if (property.name == "meta") {
+			property.usage ^= PROPERTY_USAGE_STORAGE;
+		}
+#else
+		// Don't store "Control".
+		if (property.name == "control") {
+			property.usage ^= PROPERTY_USAGE_STORAGE;
+		}
+#endif
+	} else {
+		// We don't want to store command, only control or meta (on mac).
+		if (property.name == "command") {
+			property.usage ^= PROPERTY_USAGE_STORAGE;
+		}
+	}
+}
+
 ///////////////////////////////////
 
 void InputEventKey::set_pressed(bool p_pressed) {

core/input/input_event.h

@@ -209,6 +209,8 @@ class InputEventFromWindow : public InputEvent {
 class InputEventWithModifiers : public InputEventFromWindow {
 	GDCLASS(InputEventWithModifiers, InputEventFromWindow);
 
+	bool store_command = true;
+
 	bool shift = false;
 	bool alt = false;
 #ifdef APPLE_STYLE_KEYS
@@ -228,8 +230,12 @@ class InputEventWithModifiers : public InputEventFromWindow {
 
 protected:
 	static void _bind_methods();
+	virtual void _validate_property(PropertyInfo &property) const override;
 
 public:
+	void set_store_command(bool p_enabled);
+	bool is_storing_command() const;
+
 	void set_shift(bool p_enabled);
 	bool get_shift() const;
 

doc/classes/InputEventWithModifiers.xml

@@ -27,6 +27,10 @@
 		<member name="shift" type="bool" setter="set_shift" getter="get_shift" default="false">
 			State of the [kbd]Shift[/kbd] modifier.
 		</member>
+		<member name="store_command" type="bool" setter="set_store_command" getter="is_storing_command" default="true">
+			If [code]true[/code], pressing [kbd]Cmd[/kbd] on macOS or [kbd]Ctrl[/kbd] on all other platforms will both be serialized as [member command]. If [code]false[/code], those same keys will be serialized as [member meta] on macOS and [member control] on all other platforms.
+			This aids with cross-platform compatibility when developing e.g. on Windows for macOS, or vice-versa.
+		</member>
 	</members>
 	<constants>
 	</constants>