Strict type hints for MQTT integration (#82317)

* Strict type hints for MQTT integration

* Fix errors

* Additional corrections

* Use cv.template to avoid untyped calls

* Enable strict typing policy for MQTT integration

* Use ignore[no-untyped-call]

* Use # type: ignore[unreachable]

* Correct cast

* Refactor getting discovery_payload

* Remove unused type ignore comments

.strict-typing

@@ -187,6 +187,7 @@ homeassistant.components.mjpeg.*
 homeassistant.components.modbus.*
 homeassistant.components.modem_callerid.*
 homeassistant.components.moon.*
+homeassistant.components.mqtt.*
 homeassistant.components.mysensors.*
 homeassistant.components.nam.*
 homeassistant.components.nanoleaf.*

homeassistant/components/mqtt/alarm_control_panel.py

@@ -249,7 +249,7 @@ class MqttAlarm(MqttEntity, alarm.AlarmControlPanelEntity):
     @property
     def code_arm_required(self) -> bool:
         """Whether the code is required for arm actions."""
-        return self._config[CONF_CODE_ARM_REQUIRED]
+        return bool(self._config[CONF_CODE_ARM_REQUIRED])
 
     async def async_alarm_disarm(self, code: str | None = None) -> None:
         """Send disarm command.

homeassistant/components/mqtt/client.py

@@ -80,7 +80,6 @@ if TYPE_CHECKING:
     # because integrations should be able to optionally rely on MQTT.
     import paho.mqtt.client as mqtt
 
-
 _LOGGER = logging.getLogger(__name__)
 
 DISCOVERY_COOLDOWN = 2
@@ -148,16 +147,19 @@ AsyncDeprecatedMessageCallbackType = Callable[
     [str, ReceivePayloadType, int], Coroutine[Any, Any, None]
 ]
 DeprecatedMessageCallbackType = Callable[[str, ReceivePayloadType, int], None]
+DeprecatedMessageCallbackTypes = Union[
+    AsyncDeprecatedMessageCallbackType, DeprecatedMessageCallbackType
+]
 
 
 def wrap_msg_callback(
-    msg_callback: AsyncDeprecatedMessageCallbackType | DeprecatedMessageCallbackType,
+    msg_callback: DeprecatedMessageCallbackTypes,
 ) -> AsyncMessageCallbackType | MessageCallbackType:
     """Wrap an MQTT message callback to support deprecated signature."""
     # Check for partials to properly determine if coroutine function
     check_func = msg_callback
     while isinstance(check_func, partial):
-        check_func = check_func.func
+        check_func = check_func.func  # type: ignore[unreachable]
 
     wrapper_func: AsyncMessageCallbackType | MessageCallbackType
     if asyncio.iscoroutinefunction(check_func):
@@ -170,14 +172,15 @@ def wrap_msg_callback(
             )
 
         wrapper_func = async_wrapper
-    else:
+        return wrapper_func
 
-        @wraps(msg_callback)
-        def wrapper(msg: ReceiveMessage) -> None:
-            """Call with deprecated signature."""
-            msg_callback(msg.topic, msg.payload, msg.qos)
+    @wraps(msg_callback)
+    def wrapper(msg: ReceiveMessage) -> None:
+        """Call with deprecated signature."""
+        msg_callback(msg.topic, msg.payload, msg.qos)
+
+    wrapper_func = wrapper
 
-        wrapper_func = wrapper
     return wrapper_func
 
 
@@ -187,8 +190,7 @@ async def async_subscribe(
     topic: str,
     msg_callback: AsyncMessageCallbackType
     | MessageCallbackType
-    | DeprecatedMessageCallbackType
-    | AsyncDeprecatedMessageCallbackType,
+    | DeprecatedMessageCallbackTypes,
     qos: int = DEFAULT_QOS,
     encoding: str | None = DEFAULT_ENCODING,
 ) -> CALLBACK_TYPE:
@@ -219,7 +221,7 @@ async def async_subscribe(
             msg_callback.__name__,
         )
         wrapped_msg_callback = wrap_msg_callback(
-            cast(DeprecatedMessageCallbackType, msg_callback)
+            cast(DeprecatedMessageCallbackTypes, msg_callback)
         )
 
     async_remove = await mqtt_data.client.async_subscribe(

homeassistant/components/mqtt/discovery.py

@@ -97,7 +97,7 @@ async def async_start(  # noqa: C901
     mqtt_data = get_mqtt_data(hass)
     mqtt_integrations = {}
 
-    async def async_discovery_message_received(msg) -> None:
+    async def async_discovery_message_received(msg: ReceiveMessage) -> None:
         """Process the received message."""
         mqtt_data.last_discovery = time.time()
         payload = msg.payload
@@ -122,46 +122,50 @@ async def async_start(  # noqa: C901
 
         if payload:
             try:
-                payload = json_loads(payload)
+                discovery_payload = MQTTDiscoveryPayload(json_loads(payload))
             except ValueError:
                 _LOGGER.warning("Unable to parse JSON %s: '%s'", object_id, payload)
                 return
+        else:
+            discovery_payload = MQTTDiscoveryPayload({})
 
-        payload = MQTTDiscoveryPayload(payload)
-
-        for key in list(payload):
+        for key in list(discovery_payload):
             abbreviated_key = key
             key = ABBREVIATIONS.get(key, key)
-            payload[key] = payload.pop(abbreviated_key)
+            discovery_payload[key] = discovery_payload.pop(abbreviated_key)
 
-        if CONF_DEVICE in payload:
-            device = payload[CONF_DEVICE]
+        if CONF_DEVICE in discovery_payload:
+            device = discovery_payload[CONF_DEVICE]
             for key in list(device):
                 abbreviated_key = key
                 key = DEVICE_ABBREVIATIONS.get(key, key)
                 device[key] = device.pop(abbreviated_key)
 
-        if CONF_AVAILABILITY in payload:
-            for availability_conf in cv.ensure_list(payload[CONF_AVAILABILITY]):
+        if CONF_AVAILABILITY in discovery_payload:
+            for availability_conf in cv.ensure_list(
+                discovery_payload[CONF_AVAILABILITY]
+            ):
                 if isinstance(availability_conf, dict):
                     for key in list(availability_conf):
                         abbreviated_key = key
                         key = ABBREVIATIONS.get(key, key)
                         availability_conf[key] = availability_conf.pop(abbreviated_key)
 
-        if TOPIC_BASE in payload:
-            base = payload.pop(TOPIC_BASE)
-            for key, value in payload.items():
+        if TOPIC_BASE in discovery_payload:
+            base = discovery_payload.pop(TOPIC_BASE)
+            for key, value in discovery_payload.items():
                 if isinstance(value, str) and value:
                     if value[0] == TOPIC_BASE and key.endswith("topic"):
-                        payload[key] = f"{base}{value[1:]}"
+                        discovery_payload[key] = f"{base}{value[1:]}"
                     if value[-1] == TOPIC_BASE and key.endswith("topic"):
-                        payload[key] = f"{value[:-1]}{base}"
-            if payload.get(CONF_AVAILABILITY):
-                for availability_conf in cv.ensure_list(payload[CONF_AVAILABILITY]):
+                        discovery_payload[key] = f"{value[:-1]}{base}"
+            if discovery_payload.get(CONF_AVAILABILITY):
+                for availability_conf in cv.ensure_list(
+                    discovery_payload[CONF_AVAILABILITY]
+                ):
                     if not isinstance(availability_conf, dict):
                         continue
-                    if topic := availability_conf.get(CONF_TOPIC):
+                    if topic := str(availability_conf.get(CONF_TOPIC)):
                         if topic[0] == TOPIC_BASE:
                             availability_conf[CONF_TOPIC] = f"{base}{topic[1:]}"
                         if topic[-1] == TOPIC_BASE:
@@ -171,21 +175,25 @@ async def async_start(  # noqa: C901
         discovery_id = " ".join((node_id, object_id)) if node_id else object_id
         discovery_hash = (component, discovery_id)
 
-        if payload:
+        if discovery_payload:
             # Attach MQTT topic to the payload, used for debug prints
-            setattr(payload, "__configuration_source__", f"MQTT (topic: '{topic}')")
+            setattr(
+                discovery_payload,
+                "__configuration_source__",
+                f"MQTT (topic: '{topic}')",
+            )
             discovery_data = {
                 ATTR_DISCOVERY_HASH: discovery_hash,
-                ATTR_DISCOVERY_PAYLOAD: payload,
+                ATTR_DISCOVERY_PAYLOAD: discovery_payload,
                 ATTR_DISCOVERY_TOPIC: topic,
             }
-            setattr(payload, "discovery_data", discovery_data)
+            setattr(discovery_payload, "discovery_data", discovery_data)
 
-            payload[CONF_PLATFORM] = "mqtt"
+            discovery_payload[CONF_PLATFORM] = "mqtt"
 
         if discovery_hash in mqtt_data.discovery_pending_discovered:
             pending = mqtt_data.discovery_pending_discovered[discovery_hash]["pending"]
-            pending.appendleft(payload)
+            pending.appendleft(discovery_payload)
             _LOGGER.info(
                 "Component has already been discovered: %s %s, queuing update",
                 component,
@@ -193,7 +201,9 @@ async def async_start(  # noqa: C901
             )
             return
 
-        await async_process_discovery_payload(component, discovery_id, payload)
+        await async_process_discovery_payload(
+            component, discovery_id, discovery_payload
+        )
 
     async def async_process_discovery_payload(
         component: str, discovery_id: str, payload: MQTTDiscoveryPayload
@@ -204,7 +214,7 @@ async def async_start(  # noqa: C901
         discovery_hash = (component, discovery_id)
         if discovery_hash in mqtt_data.discovery_already_discovered or payload:
 
-            async def discovery_done(_) -> None:
+            async def discovery_done(_: Any) -> None:
                 pending = mqtt_data.discovery_pending_discovered[discovery_hash][
                     "pending"
                 ]

homeassistant/components/mqtt/light/schema_basic.py

@@ -680,7 +680,7 @@ class MqttLight(MqttEntity, LightEntity, RestoreEntity):
         restore_state(ATTR_HS_COLOR, ATTR_XY_COLOR)
 
     @property
-    def assumed_state(self):
+    def assumed_state(self) -> bool:
         """Return true if we do optimistic updates."""
         return self._optimistic
 

homeassistant/components/mqtt/mixins.py

@@ -620,7 +620,8 @@ async def cleanup_device_registry(
 
 def get_discovery_hash(discovery_data: DiscoveryInfoType) -> tuple[str, str]:
     """Get the discovery hash from the discovery data."""
-    return discovery_data[ATTR_DISCOVERY_HASH]
+    discovery_hash: tuple[str, str] = discovery_data[ATTR_DISCOVERY_HASH]
+    return discovery_hash
 
 
 def send_discovery_done(hass: HomeAssistant, discovery_data: DiscoveryInfoType) -> None:
@@ -1113,7 +1114,7 @@ class MqttEntity(
     @property
     def entity_registry_enabled_default(self) -> bool:
         """Return if the entity should be enabled when first added to the entity registry."""
-        return self._config[CONF_ENABLED_BY_DEFAULT]
+        return bool(self._config[CONF_ENABLED_BY_DEFAULT])
 
     @property
     def entity_category(self) -> EntityCategory | None:

homeassistant/components/mqtt/models.py

@@ -150,7 +150,7 @@ class MqttCommandTemplate:
         if self._entity:
             values[ATTR_ENTITY_ID] = self._entity.entity_id
             values[ATTR_NAME] = self._entity.name
-            if not self._template_state:
+            if not self._template_state and self._command_template.hass is not None:
                 self._template_state = template.TemplateStateFromEntityId(
                     self._entity.hass, self._entity.entity_id
                 )
@@ -200,6 +200,8 @@ class MqttValueTemplate:
         variables: TemplateVarsType = None,
     ) -> ReceivePayloadType:
         """Render with possible json value or pass-though a received MQTT value."""
+        rendered_payload: ReceivePayloadType
+
         if self._value_template is None:
             return payload
 
@@ -227,9 +229,12 @@ class MqttValueTemplate:
                 values,
                 self._value_template,
             )
-            return self._value_template.async_render_with_possible_json_value(
-                payload, variables=values
+            rendered_payload = (
+                self._value_template.async_render_with_possible_json_value(
+                    payload, variables=values
+                )
             )
+            return rendered_payload
 
         _LOGGER.debug(
             "Rendering incoming payload '%s' with variables %s with default value '%s' and %s",
@@ -238,9 +243,10 @@ class MqttValueTemplate:
             default,
             self._value_template,
         )
-        return self._value_template.async_render_with_possible_json_value(
+        rendered_payload = self._value_template.async_render_with_possible_json_value(
             payload, default, variables=values
         )
+        return rendered_payload
 
 
 class EntityTopicState:

homeassistant/components/mqtt/subscription.py

@@ -19,7 +19,7 @@ class EntitySubscription:
     """Class to hold data about an active entity topic subscription."""
 
     hass: HomeAssistant = attr.ib()
-    topic: str = attr.ib()
+    topic: str | None = attr.ib()
     message_callback: MessageCallbackType = attr.ib()
     subscribe_task: Coroutine[Any, Any, Callable[[], None]] | None = attr.ib()
     unsubscribe_callback: Callable[[], None] | None = attr.ib()
@@ -39,7 +39,7 @@ class EntitySubscription:
             other.unsubscribe_callback()
             # Clear debug data if it exists
             debug_info.remove_subscription(
-                self.hass, other.message_callback, other.topic
+                self.hass, other.message_callback, str(other.topic)
             )
 
         if self.topic is None:
@@ -112,7 +112,7 @@ def async_prepare_subscribe_topics(
             remaining.unsubscribe_callback()
             # Clear debug data if it exists
             debug_info.remove_subscription(
-                hass, remaining.message_callback, remaining.topic
+                hass, remaining.message_callback, str(remaining.topic)
             )
 
     return new_state

homeassistant/components/mqtt/util.py

@@ -97,7 +97,7 @@ def valid_subscribe_topic(topic: Any) -> str:
 
 def valid_subscribe_topic_template(value: Any) -> template.Template:
     """Validate either a jinja2 template or a valid MQTT subscription topic."""
-    tpl = template.Template(value)
+    tpl = cv.template(value)
 
     if tpl.is_static:
         valid_subscribe_topic(value)
@@ -115,7 +115,8 @@ def valid_publish_topic(topic: Any) -> str:
 
 def valid_qos_schema(qos: Any) -> int:
     """Validate that QOS value is valid."""
-    return _VALID_QOS_SCHEMA(qos)
+    validated_qos: int = _VALID_QOS_SCHEMA(qos)
+    return validated_qos
 
 
 _MQTT_WILL_BIRTH_SCHEMA = vol.Schema(
@@ -138,9 +139,12 @@ def valid_birth_will(config: ConfigType) -> ConfigType:
 
 def get_mqtt_data(hass: HomeAssistant, ensure_exists: bool = False) -> MqttData:
     """Return typed MqttData from hass.data[DATA_MQTT]."""
+    mqtt_data: MqttData
     if ensure_exists:
-        return hass.data.setdefault(DATA_MQTT, MqttData())
-    return hass.data[DATA_MQTT]
+        mqtt_data = hass.data.setdefault(DATA_MQTT, MqttData())
+        return mqtt_data
+    mqtt_data = hass.data[DATA_MQTT]
+    return mqtt_data
 
 
 async def async_create_certificate_temp_files(

mypy.ini

@@ -1623,6 +1623,16 @@ disallow_untyped_defs = true
 warn_return_any = true
 warn_unreachable = true
 
+[mypy-homeassistant.components.mqtt.*]
+check_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+warn_return_any = true
+warn_unreachable = true
+
 [mypy-homeassistant.components.mysensors.*]
 check_untyped_defs = true
 disallow_incomplete_defs = true