Google Assistant and Homekit sending wrong target temp values

[joshtbernstein]

Home Assistant release with the issue:

0.82.1

Last working Home Assistant release (if known):

Operating environment (Hass.io/Docker/Windows/etc.):

Hass.io on Docker on CentOS 7

Component/platform:

Description of problem:
If I choose a temperature of 73°F in Google Assistant, the value of 72.99999122619629 is sent to my thermostat. My thermostat rounds this down to 72°F so I can not actually set a target temp of 73.

If I choose a temperature of 75°F in HomeKit, the value of 74.7 is sent to my thermostat. My thermostat rounds this down to 74°F so I can not actually set a target temp of 75.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

cloud:

homekit:
  auto_start: false


climate:
  - platform: mqtt
    name: Thermostat
    modes:
      - "off"
      - "heat"
      - "cool"
    fan_modes:
      - "Auto"
      - "On"
    current_temperature_topic: "hvac/current_temperature"
    mode_command_topic: "hvac/mode/set"
    mode_state_topic: "hvac/mode/get"
    temperature_command_topic: "hvac/temperature/set"
    temperature_state_topic: "hvac/temperature/get"
    fan_mode_command_topic: "hvac/fan/set"
    fan_mode_state_topic: "hvac/fan/get"
    availability_topic: "hvac/availability"
    min_temp: 45
    max_temp: 95

Traceback (if applicable):

Additional information:
It looks like both components are working in Celsius and then converting to Fahrenheit. Ideally the components should work in the user's native unit measurement system (from configuration.yaml), but a possible short term fix would be to send a rounded integer to the thermostat.

[cdce8p]

I only know the situation with HomeKit: The Home App uses Celsius internally, but only rounded to the nearest 0 or .5 value. That's the one which is then send to Home Assistant where it's converted back to Fahrenheit also with another rounding to the nearest 0 or .5 value. Unfortunately that's the way it has to be done with unit conversions.

I tried setting the temperature to 75°F in the Home App myself. However it all worked fine for me. The temp target from HomeKit was 24.0°C (75.2°F) which was converted to 75°F by Home Assistant and used for the service call.

[marchingphoenix]

Need to add rounding to the execute() function for all commands.
https://github.com/home-assistant/home-assistant/blob/dev/homeassistant/components/google_assistant/trait.py#L583