exception setting value with many decimals

[marcusb]

Stepping the temperature setpoint on a thermostat with the BasicUI controls, with the thermostat configured for Celsius, frequently results in a floating-point value with a lot of decimals being sent to the channel, even if the starting value was an integer. This causes an exception in the binding, which seems to error out on high-precision numbers.

There is of course no value in keeping all these decimals, they are just a rounding artefact. I think the binding should discard them.

Observed behavior: The change does not take effect.

Expected behavior: Lowering the temperature works. Rounding happens where needed (presumably in the binding).

• OH2 Version: 3.1.0 (openhabian)
• Binding Version: 3.2.0-SNAPSHOT on commit d0392a2
• Device: Radio Thermostat CT101

Debug log:

2021-10-10 22:05:32.077 [DEBUG] [ding.zwave.handler.ZWaveThingHandler] - NODE 25: Command received zwave:device:512:node25:thermostat_setpoint_cooling --> 23.38888888888889 °C [QuantityType]
2021-10-10 22:05:32.078 [DEBUG] [ter.ZWaveThermostatSetpointConverter] - NODE 25: Thermostat command received for 23.38888888888889 °C
2021-10-10 22:05:32.079 [DEBUG] [.ZWaveThermostatSetpointCommandClass] - NODE 25: Creating new message for command THERMOSTAT_SETPOINT_SET
2021-10-10 22:05:32.079 [ERROR] [.ZWaveThermostatSetpointCommandClass] - NODE 25: Got an arithmetic exception converting value 23.38888888888889 to a valid Z-Wave value. Ignoring THERMOSTAT_SETPOINT_SET message.
2021-10-10 22:05:32.080 [WARN ] [ter.ZWaveThermostatSetpointConverter] - NODE 25: Generating message failed for command class = COMMAND_CLASS_THERMOSTAT_SETPOINT, endpoint = 0
2021-10-10 22:05:32.081 [DEBUG] [ding.zwave.handler.ZWaveThingHandler] - NODE 25: No messages returned from converter

This appears to be the same bug as openhab/openhab1-addons#3794.