Human:getVehicle() causes Lua error when null

[Deewarz]

Description

If we try to get the player's vehicle while he is not in it, we get this error:

Lua error: (straight from the exception): Entity handle '18446744073709551615' is invalid!
[2025-01-12 00:53:58.189] [error] Entity handle '18446744073709551615' is invalid!
stack traceback:
        [C]: in method 'getVehicle'
        gamemode/server/main.lua:118: in local 'foundCommand'
        gamemode/server/main.lua:99: in function <gamemode/server/main.lua:89>

Reproduction

When not in vehicle, connected to a server, type /bug in chat

listenEvent("onChatCommand", function (player, message, command, args)
  if command == "bug" then
    local veh = player:getVehicle() -- causes issue
  end
end)

Possible reason

This could be related to the Human:getVehicle() function which returns Vehicle(-1).
Could we return null / nil instead?

MafiaMP/code/server/src/core/builtins/human.cpp

Lines 36 to 43 in b4dfb16

	Vehicle Human::GetVehicle() const {
	const auto updateData = _ent.get<MafiaMP::Shared::Modules::HumanSync::UpdateData>();
	const auto carEnt = flecs::entity(_ent.world(), updateData->carPassenger.carId);
	if (carEnt.is_valid() && carEnt.is_alive()) {
	return Vehicle(carEnt);
	}
	return Vehicle(-1);
	}

[zpl-zak]

Check if we can return std::optional<Vehicle> here so that null can be returned in Lua VM.

EDIT: sol3 lua wrapper already has an optional<> abstraction, see if it's of any use before using std::optional
https://github.com/ThePhD/sol2/blob/develop/include/sol/optional.hpp