Only subscribe when MQTT client is connected. (#34557)

homeassistant/components/mqtt/__init__.py

@@ -872,7 +872,9 @@ class MQTT:
         subscription = Subscription(topic, msg_callback, qos, encoding)
         self.subscriptions.append(subscription)
 
-        await self._async_perform_subscription(topic, qos)
+        # Only subscribe if currently connected.
+        if self.connected:
+            await self._async_perform_subscription(topic, qos)
 
         @callback
         def async_remove() -> None:

tests/components/mqtt/test_init.py

@@ -580,6 +580,9 @@ class TestMQTTCallbacks(unittest.TestCase):
 
         self.hass.data["mqtt"]._mqttc.subscribe.side_effect = side_effect
 
+        # Fake that the client is connected
+        self.hass.data["mqtt"].connected = True
+
         calls_a = mock.MagicMock()
         mqtt.subscribe(self.hass, "test/state", calls_a)
         self.hass.block_till_done()
@@ -592,6 +595,9 @@ class TestMQTTCallbacks(unittest.TestCase):
 
     def test_not_calling_unsubscribe_with_active_subscribers(self):
         """Test not calling unsubscribe() when other subscribers are active."""
+        # Fake that the client is connected
+        self.hass.data["mqtt"].connected = True
+
         unsub = mqtt.subscribe(self.hass, "test/state", None)
         mqtt.subscribe(self.hass, "test/state", None)
         self.hass.block_till_done()
@@ -603,6 +609,9 @@ class TestMQTTCallbacks(unittest.TestCase):
 
     def test_restore_subscriptions_on_reconnect(self):
         """Test subscriptions are restored on reconnect."""
+        # Fake that the client is connected
+        self.hass.data["mqtt"].connected = True
+
         mqtt.subscribe(self.hass, "test/state", None)
         self.hass.block_till_done()
         assert self.hass.data["mqtt"]._mqttc.subscribe.call_count == 1
@@ -614,6 +623,9 @@ class TestMQTTCallbacks(unittest.TestCase):
 
     def test_restore_all_active_subscriptions_on_reconnect(self):
         """Test active subscriptions are restored correctly on reconnect."""
+        # Fake that the client is connected
+        self.hass.data["mqtt"].connected = True
+
         self.hass.data["mqtt"]._mqttc.subscribe.side_effect = (
             (0, 1),
             (0, 2),