evcc panic when setting a value via MQTT

[emcepe]

Describe the bug

I like to set a guest vehicle via the MQTT api but didn't find out how to do it, so I did trial & error :)

if I set "loadpoints/1/vehicle/set" to -1, then:

Oct 16 23:24:16 raspberry-pi-4b systemd[1]: evcc.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
Oct 16 23:24:16 raspberry-pi-4b systemd[1]: evcc.service: Failed with result 'exit-code'.
Oct 16 23:24:16 raspberry-pi-4b systemd[1]: evcc.service: Consumed 3.409s CPU time.
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: panic: runtime error: index out of range [-1]
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: goroutine 63 [running]:
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: github.com/evcc-io/evcc/server.(*MQTT).listenSetters.func7({0x4b74de2, 0x2})
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: #011/Users/andig/htdocs/evcc/server/mqtt.go:121 +0xb8
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: github.com/evcc-io/evcc/provider/mqtt.(*Client).ListenSetter.func1({0x4b74de2, 0x2})
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: #011/Users/andig/htdocs/evcc/provider/mqtt/client.go:147 +0x44
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: github.com/evcc-io/evcc/provider/mqtt.(*Client).listen.func1({0x1bdb94c, 0x4927ce0}, {0x1bd9aa0, 0x4fd8660})
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: #011/Users/andig/htdocs/evcc/provider/mqtt/client.go:165 +0x180
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: github.com/eclipse/paho%2emqtt%2egolang.(*router).matchAndDispatch.func2()
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: #011/Users/andig/go/pkg/mod/github.com/eclipse/[email protected]/router.go:214 +0x7b8
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: created by github.com/eclipse/paho%2emqtt%2egolang.(*router).matchAndDispatch
Oct 16 23:24:16 raspberry-pi-4b evcc[4328]: #011/Users/andig/go/pkg/mod/github.com/eclipse/[email protected]/router.go:173 +0x268

so I guess -1 is wrong to set a guest vehicle ;-)

is it possible to set that via MQTT?

Steps to reproduce

MQTT publish -1 to loadpoints/1/vehicle/set

Configuration details

not needed

Log details

not needed

What type of operating system are you running?

Linux

Version

0.105.2