[Bug] [Scripting] Vehicle:setLicensePlate() is not working properly

[Deewarz]

Description

If we try to update the license plate of a vehicle other than empty, nothing happens.

Reproduction

When in vehicle:

listenEvent("onChatCommand", function (player, message, command, args)
  if command == "plate" then
    local veh = player:getVehicle()

    if veh == nil then
      return
    end

    local licensePlate = args[1] or ""
    veh:setLicensePlate(licensePlate)
  end
end)

Possible reason

Could be related to the way we manage the string here:

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

Lines 128 to 134 in b4dfb16

	void Vehicle::SetLicensePlate(std::string plate) {
	auto vehData = _ent.get_mut<Shared::Modules::VehicleSync::UpdateData>();
	::memcpy(vehData->licensePlate, plate.c_str(), std::min(sizeof(vehData->licensePlate), plate.length()));
	MafiaMP::Shared::RPC::VehicleSetProps msg {};
	msg.licensePlate = plate.c_str();
	FW_SEND_SERVER_COMPONENT_GAME_RPC(Shared::RPC::VehicleSetProps, _ent, msg);
	}

[zpl-zak]

Could you check if we hit this condition on client-side and whether it carries any value at all?

MafiaMP/code/client/src/core/modules/vehicle.cpp

Lines 342 to 345 in b4dfb16

	if (licensePlate.HasValue()) {
	const auto plate = licensePlate().C_String();
	::memcpy(updateData->licensePlate, plate, strlen(plate) + 1);
	}

Also check if msg validation passes or fails here:

MafiaMP/code/shared/game_rpc/vehicle/vehicle_setprops.h

Lines 63 to 65 in b4dfb16

	if (licensePlate.HasValue() && licensePlate().GetLength() > 7) {
	return false;
	}

[Deewarz]

After analysis, the bug is related to this code:

MafiaMP/code/client/src/core/modules/vehicle.cpp

Lines 214 to 216 in b4dfb16

	if (::strcmp(vehicle->GetSPZText(), updateData->licensePlate) > 0) {
	vehicle->SetSPZText(updateData->licensePlate, true);
	}

The comparison should check if it is not equal to zero. (https://en.cppreference.com/w/cpp/string/byte/strcmp)

Fix incoming