Make mqtt internal subscription a normal function (#118092)

Co-authored-by: Jan Bouwhuis <jbouwh@users.noreply.github.com>

homeassistant/components/mqtt/client.py

@@ -191,13 +191,25 @@ async def async_subscribe(
 
     Call the return value to unsubscribe.
     """
-    if not mqtt_config_entry_enabled(hass):
-        raise HomeAssistantError(
-            f"Cannot subscribe to topic '{topic}', MQTT is not enabled",
-            translation_key="mqtt_not_setup_cannot_subscribe",
-            translation_domain=DOMAIN,
-            translation_placeholders={"topic": topic},
-        )
+    return async_subscribe_internal(hass, topic, msg_callback, qos, encoding)
+
+
+@callback
+def async_subscribe_internal(
+    hass: HomeAssistant,
+    topic: str,
+    msg_callback: Callable[[ReceiveMessage], Coroutine[Any, Any, None] | None],
+    qos: int = DEFAULT_QOS,
+    encoding: str | None = DEFAULT_ENCODING,
+) -> CALLBACK_TYPE:
+    """Subscribe to an MQTT topic.
+
+    This function is internal to the MQTT integration
+    and may change at any time. It should not be considered
+    a stable API.
+
+    Call the return value to unsubscribe.
+    """
     try:
         mqtt_data = hass.data[DATA_MQTT]
     except KeyError as exc:
@@ -208,12 +220,15 @@ async def async_subscribe(
             translation_domain=DOMAIN,
             translation_placeholders={"topic": topic},
         ) from exc
-    return await mqtt_data.client.async_subscribe(
-        topic,
-        msg_callback,
-        qos,
-        encoding,
-    )
+    client = mqtt_data.client
+    if not client.connected and not mqtt_config_entry_enabled(hass):
+        raise HomeAssistantError(
+            f"Cannot subscribe to topic '{topic}', MQTT is not enabled",
+            translation_key="mqtt_not_setup_cannot_subscribe",
+            translation_domain=DOMAIN,
+            translation_placeholders={"topic": topic},
+        )
+    return client.async_subscribe(topic, msg_callback, qos, encoding)
 
 
 @bind_hass
@@ -845,17 +860,15 @@ class MQTT:
             f"'{msg.topic}': '{msg.payload}'"  # type: ignore[str-bytes-safe]
         )
 
-    async def async_subscribe(
+    @callback
+    def async_subscribe(
         self,
         topic: str,
         msg_callback: Callable[[ReceiveMessage], Coroutine[Any, Any, None] | None],
         qos: int,
         encoding: str | None = None,
     ) -> Callable[[], None]:
-        """Set up a subscription to a topic with the provided qos.
-
-        This method is a coroutine.
-        """
+        """Set up a subscription to a topic with the provided qos."""
         if not isinstance(topic, str):
             raise HomeAssistantError("Topic needs to be a string!")
 
@@ -881,18 +894,18 @@ class MQTT:
         if self.connected:
             self._async_queue_subscriptions(((topic, qos),))
 
-        @callback
-        def async_remove() -> None:
-            """Remove subscription."""
-            self._async_untrack_subscription(subscription)
-            self._matching_subscriptions.cache_clear()
-            if subscription in self._retained_topics:
-                del self._retained_topics[subscription]
-            # Only unsubscribe if currently connected
-            if self.connected:
-                self._async_unsubscribe(topic)
+        return partial(self._async_remove, subscription)
 
-        return async_remove
+    @callback
+    def _async_remove(self, subscription: Subscription) -> None:
+        """Remove subscription."""
+        self._async_untrack_subscription(subscription)
+        self._matching_subscriptions.cache_clear()
+        if subscription in self._retained_topics:
+            del self._retained_topics[subscription]
+        # Only unsubscribe if currently connected
+        if self.connected:
+            self._async_unsubscribe(subscription.topic)
 
     @callback
     def _async_unsubscribe(self, topic: str) -> None: