Add type hints for MQTT tag (#81495)

* Improve typing tag

* Additional type hints for tag platform

* Follow up comment tag

* Folow up comments

* Revert comment removal

homeassistant/components/mqtt/tag.py

@@ -1,6 +1,7 @@
 """Provides tag scanning for MQTT."""
 from __future__ import annotations
 
+from collections.abc import Callable
 import functools
 
 import voluptuous as vol
@@ -9,11 +10,12 @@ from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import CONF_DEVICE, CONF_PLATFORM, CONF_VALUE_TEMPLATE
 from homeassistant.core import HomeAssistant
 import homeassistant.helpers.config_validation as cv
-from homeassistant.helpers.typing import ConfigType
+from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
 
 from . import subscription
 from .config import MQTT_BASE_SCHEMA
 from .const import ATTR_DISCOVERY_HASH, CONF_QOS, CONF_TOPIC
+from .discovery import MQTTDiscoveryPayload
 from .mixins import (
     MQTT_ENTITY_DEVICE_INFO_SCHEMA,
     MqttDiscoveryDeviceUpdate,
@@ -21,7 +23,7 @@ from .mixins import (
     send_discovery_done,
     update_device,
 )
-from .models import MqttValueTemplate, ReceiveMessage
+from .models import MqttValueTemplate, ReceiveMessage, ReceivePayloadType
 from .subscription import EntitySubscription
 from .util import get_mqtt_data, valid_subscribe_topic
 
@@ -87,12 +89,14 @@ def async_has_tags(hass: HomeAssistant, device_id: str) -> bool:
 class MQTTTagScanner(MqttDiscoveryDeviceUpdate):
     """MQTT Tag scanner."""
 
+    _value_template: Callable[[ReceivePayloadType, str], ReceivePayloadType]
+
     def __init__(
         self,
         hass: HomeAssistant,
         config: ConfigType,
         device_id: str | None,
-        discovery_data: dict,
+        discovery_data: DiscoveryInfoType,
         config_entry: ConfigEntry,
     ) -> None:
         """Initialize."""
@@ -111,10 +115,10 @@ class MQTTTagScanner(MqttDiscoveryDeviceUpdate):
             self, hass, discovery_data, device_id, config_entry, LOG_NAME
         )
 
-    async def async_update(self, discovery_data: dict) -> None:
+    async def async_update(self, discovery_data: MQTTDiscoveryPayload) -> None:
         """Handle MQTT tag discovery updates."""
         # Update tag scanner
-        config = PLATFORM_SCHEMA(discovery_data)
+        config: DiscoveryInfoType = PLATFORM_SCHEMA(discovery_data)
         self._config = config
         self._value_template = MqttValueTemplate(
             config.get(CONF_VALUE_TEMPLATE),
@@ -127,7 +131,7 @@ class MQTTTagScanner(MqttDiscoveryDeviceUpdate):
         """Subscribe to MQTT topics."""
 
         async def tag_scanned(msg: ReceiveMessage) -> None:
-            tag_id = self._value_template(msg.payload, "").strip()
+            tag_id = str(self._value_template(msg.payload, "")).strip()
             if not tag_id:  # No output from template, ignore
                 return