Fix mqtt climate initial temperature conversion and precision (#93965)

* Fix mqtt climate initial temperature conversion

* Avoid changing hass temperature_unit

* Update comment

homeassistant/components/mqtt/climate.py

@@ -15,9 +15,7 @@ from homeassistant.components.climate import (
     ATTR_TARGET_TEMP_HIGH,
     ATTR_TARGET_TEMP_LOW,
     DEFAULT_MAX_HUMIDITY,
-    DEFAULT_MAX_TEMP,
     DEFAULT_MIN_HUMIDITY,
-    DEFAULT_MIN_TEMP,
     FAN_AUTO,
     FAN_HIGH,
     FAN_LOW,
@@ -42,12 +40,14 @@ from homeassistant.const import (
     PRECISION_HALVES,
     PRECISION_TENTHS,
     PRECISION_WHOLE,
+    UnitOfTemperature,
 )
 from homeassistant.core import HomeAssistant, callback
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.template import Template
 from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
+from homeassistant.util.unit_conversion import TemperatureConverter
 
 from . import subscription
 from .config import DEFAULT_RETAIN, MQTT_BASE_SCHEMA
@@ -150,6 +150,8 @@ CONF_TEMP_MAX = "max_temp"
 CONF_TEMP_MIN = "min_temp"
 CONF_TEMP_STEP = "temp_step"
 
+DEFAULT_INITIAL_TEMPERATURE = 21.0
+
 MQTT_CLIMATE_ATTRIBUTES_BLOCKED = frozenset(
     {
         climate.ATTR_AUX_HEAT,
@@ -338,9 +340,9 @@ _PLATFORM_SCHEMA_BASE = MQTT_BASE_SCHEMA.extend(
         ): cv.ensure_list,
         vol.Optional(CONF_SWING_MODE_STATE_TEMPLATE): cv.template,
         vol.Optional(CONF_SWING_MODE_STATE_TOPIC): valid_subscribe_topic,
-        vol.Optional(CONF_TEMP_INITIAL, default=21): cv.positive_int,
+        vol.Optional(CONF_TEMP_INITIAL): cv.positive_int,
-        vol.Optional(CONF_TEMP_MIN, default=DEFAULT_MIN_TEMP): vol.Coerce(float),
+        vol.Optional(CONF_TEMP_MIN): vol.Coerce(float),
-        vol.Optional(CONF_TEMP_MAX, default=DEFAULT_MAX_TEMP): vol.Coerce(float),
+        vol.Optional(CONF_TEMP_MAX): vol.Coerce(float),
         vol.Optional(CONF_TEMP_STEP, default=1.0): vol.Coerce(float),
         vol.Optional(CONF_TEMP_COMMAND_TEMPLATE): cv.template,
         vol.Optional(CONF_TEMP_COMMAND_TOPIC): valid_publish_topic,
@@ -443,6 +445,9 @@ class MqttTemperatureControlEntity(MqttEntity, ABC):
     climate and water_heater platforms.
     """
 
+    _attr_target_temperature_low: float | None
+    _attr_target_temperature_high: float | None
+
     _optimistic: bool
     _topic: dict[str, Any]
 
@@ -637,7 +642,7 @@ class MqttTemperatureControlEntity(MqttEntity, ABC):
         self.async_write_ha_state()
 
 
-class MqttClimate(MqttTemperatureControlEntity, ClimateEntity):  # type: ignore[misc]
+class MqttClimate(MqttTemperatureControlEntity, ClimateEntity):
     """Representation of an MQTT climate device."""
 
     _entity_id_format = climate.ENTITY_ID_FORMAT
@@ -668,28 +673,41 @@ class MqttClimate(MqttTemperatureControlEntity, ClimateEntity):  # type: ignore[
     def _setup_from_config(self, config: ConfigType) -> None:
         """(Re)Setup the entity."""
         self._attr_hvac_modes = config[CONF_MODE_LIST]
-        self._attr_min_temp = config[CONF_TEMP_MIN]
+        # Make sure the min an max temp is converted to the correct when not set
-        self._attr_max_temp = config[CONF_TEMP_MAX]
-        self._attr_min_humidity = config[CONF_HUMIDITY_MIN]
-        self._attr_max_humidity = config[CONF_HUMIDITY_MAX]
-        self._attr_precision = config.get(CONF_PRECISION, super().precision)
-        self._attr_fan_modes = config[CONF_FAN_MODE_LIST]
-        self._attr_swing_modes = config[CONF_SWING_MODE_LIST]
-        self._attr_target_temperature_step = config[CONF_TEMP_STEP]
         self._attr_temperature_unit = config.get(
             CONF_TEMPERATURE_UNIT, self.hass.config.units.temperature_unit
         )
+        if (min_temp := config.get(CONF_TEMP_MIN)) is not None:
+            self._attr_min_temp = min_temp
+        if (max_temp := config.get(CONF_TEMP_MAX)) is not None:
+            self._attr_max_temp = max_temp
+        self._attr_min_humidity = config[CONF_HUMIDITY_MIN]
+        self._attr_max_humidity = config[CONF_HUMIDITY_MAX]
+        if (precision := config.get(CONF_PRECISION)) is not None:
+            self._attr_precision = precision
+        self._attr_fan_modes = config[CONF_FAN_MODE_LIST]
+        self._attr_swing_modes = config[CONF_SWING_MODE_LIST]
+        self._attr_target_temperature_step = config[CONF_TEMP_STEP]
 
         self._topic = {key: config.get(key) for key in TOPIC_KEYS}
 
         self._optimistic = config[CONF_OPTIMISTIC]
 
+        # Set init temp, if it is missing convert the default to the temperature units
+        init_temp: float = config.get(
+            CONF_TEMP_INITIAL,
+            TemperatureConverter.convert(
+                DEFAULT_INITIAL_TEMPERATURE,
+                UnitOfTemperature.CELSIUS,
+                self.temperature_unit,
+            ),
+        )
         if self._topic[CONF_TEMP_STATE_TOPIC] is None or self._optimistic:
-            self._attr_target_temperature = config[CONF_TEMP_INITIAL]
+            self._attr_target_temperature = init_temp
         if self._topic[CONF_TEMP_LOW_STATE_TOPIC] is None or self._optimistic:
-            self._attr_target_temperature_low = config[CONF_TEMP_INITIAL]
+            self._attr_target_temperature_low = init_temp
         if self._topic[CONF_TEMP_HIGH_STATE_TOPIC] is None or self._optimistic:
-            self._attr_target_temperature_high = config[CONF_TEMP_INITIAL]
+            self._attr_target_temperature_high = init_temp
 
         if self._topic[CONF_FAN_MODE_STATE_TOPIC] is None or self._optimistic:
             self._attr_fan_mode = FAN_LOW

tests/components/mqtt/test_climate.py

@@ -27,8 +27,11 @@ from homeassistant.components.climate import (
     HVACAction,
     HVACMode,
 )
-from homeassistant.components.mqtt.climate import MQTT_CLIMATE_ATTRIBUTES_BLOCKED
+from homeassistant.components.mqtt.climate import (
-from homeassistant.const import ATTR_TEMPERATURE, Platform
+    DEFAULT_INITIAL_TEMPERATURE,
+    MQTT_CLIMATE_ATTRIBUTES_BLOCKED,
+)
+from homeassistant.const import ATTR_TEMPERATURE, Platform, UnitOfTemperature
 from homeassistant.core import HomeAssistant
 
 from .test_common import (
@@ -1690,12 +1693,97 @@ async def test_temperature_unit(
     """Test that setting temperature unit converts temperature values."""
     await mqtt_mock_entry()
 
+    state = hass.states.get(ENTITY_CLIMATE)
+    assert state.attributes.get("temperature") == DEFAULT_INITIAL_TEMPERATURE
+    assert state.attributes.get("min_temp") == DEFAULT_MIN_TEMP
+    assert state.attributes.get("max_temp") == DEFAULT_MAX_TEMP
+
     async_fire_mqtt_message(hass, "current_temperature", "77")
 
     state = hass.states.get(ENTITY_CLIMATE)
     assert state.attributes.get("current_temperature") == 25
 
 
+@pytest.mark.parametrize(
+    ("hass_config", "temperature_unit", "initial", "min", "max", "current"),
+    [
+        (
+            help_custom_config(
+                climate.DOMAIN,
+                DEFAULT_CONFIG,
+                (
+                    {
+                        "temperature_unit": "F",
+                        "current_temperature_topic": "current_temperature",
+                    },
+                ),
+            ),
+            UnitOfTemperature.CELSIUS,
+            DEFAULT_INITIAL_TEMPERATURE,
+            DEFAULT_MIN_TEMP,
+            DEFAULT_MAX_TEMP,
+            25,
+        ),
+        (
+            help_custom_config(
+                climate.DOMAIN,
+                DEFAULT_CONFIG,
+                (
+                    {
+                        "temperature_unit": "F",
+                        "current_temperature_topic": "current_temperature",
+                    },
+                ),
+            ),
+            UnitOfTemperature.KELVIN,
+            294,
+            280,
+            308,
+            298,
+        ),
+        (
+            help_custom_config(
+                climate.DOMAIN,
+                DEFAULT_CONFIG,
+                (
+                    {
+                        "temperature_unit": "F",
+                        "current_temperature_topic": "current_temperature",
+                    },
+                ),
+            ),
+            UnitOfTemperature.FAHRENHEIT,
+            70,
+            45,
+            95,
+            77,
+        ),
+    ],
+)
+async def test_alt_temperature_unit(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+    temperature_unit: UnitOfTemperature,
+    initial: float,
+    min: float,
+    max: float,
+    current: float,
+) -> None:
+    """Test deriving the systems temperature unit."""
+    with patch.object(hass.config.units, "temperature_unit", temperature_unit):
+        await mqtt_mock_entry()
+
+        state = hass.states.get(ENTITY_CLIMATE)
+        assert state.attributes.get("temperature") == initial
+        assert state.attributes.get("min_temp") == min
+        assert state.attributes.get("max_temp") == max
+
+        async_fire_mqtt_message(hass, "current_temperature", "77")
+
+        state = hass.states.get(ENTITY_CLIMATE)
+        assert state.attributes.get("current_temperature") == current
+
+
 async def test_setting_attribute_via_mqtt_json_message(
     hass: HomeAssistant, mqtt_mock_entry: MqttMockHAClientGenerator
 ) -> None: