Only import MQTT in Fully Kiosk once it is set up (#183289)

Co-authored-by: Claude <noreply@anthropic.com>

homeassistant/components/fully_kiosk/entity.py

@@ -1,10 +1,10 @@
 """Base entity for the Fully Kiosk Browser integration."""
 
 import json
+from typing import TYPE_CHECKING
 
 from yarl import URL
 
-from homeassistant.components import mqtt
 from homeassistant.const import ATTR_CONNECTIONS
 from homeassistant.core import CALLBACK_TYPE, callback
 from homeassistant.helpers.device_registry import CONNECTION_NETWORK_MAC, DeviceInfo
@@ -14,6 +14,9 @@ from homeassistant.helpers.update_coordinator import CoordinatorEntity
 from .const import DOMAIN
 from .coordinator import FullyKioskDataUpdateCoordinator
 
+if TYPE_CHECKING:
+    from homeassistant.components.mqtt import ReceiveMessage
+
 
 def valid_global_mac_address(mac: str | None) -> bool:
     """Check if a MAC address is valid, non-locally administered address."""
@@ -65,15 +68,21 @@ class FullyKioskEntity(CoordinatorEntity[FullyKioskDataUpdateCoordinator], Entit
     ) -> CALLBACK_TYPE | None:
         """Subscribe to MQTT for a given event."""
         data = self.coordinator.data
+        # MQTT is only imported once it is set up, as it is heavy to load
         if (
             event is None
-            or not mqtt.mqtt_config_entry_enabled(self.hass)
+            or "mqtt" not in self.hass.config.components
             or not data["settings"]["mqttEnabled"]
         ):
             return None
 
+        from homeassistant.components import mqtt  # noqa: PLC0415
+
+        if not mqtt.mqtt_config_entry_enabled(self.hass):
+            return None
+
         @callback
-        def message_callback(message: mqtt.ReceiveMessage) -> None:
+        def message_callback(message: ReceiveMessage) -> None:
             payload = json.loads(message.payload)
             if "event" in payload and payload["event"] == event:
                 event_callback(**payload)

tests/components/fully_kiosk/test_switch.py

@@ -1,6 +1,8 @@
 """Test the Fully Kiosk Browser switches."""
 
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
+
+import pytest
 
 from homeassistant.components import switch
 from homeassistant.components.fully_kiosk.const import DOMAIN
@@ -141,6 +143,21 @@ async def test_switches_mqtt_update(
     assert entity.state == "on"
 
 
+@pytest.mark.usefixtures("mock_fully_kiosk")
+async def test_switches_mqtt_config_entry_not_enabled(
+    hass: HomeAssistant, mock_config_entry: MockConfigEntry
+) -> None:
+    """Test no MQTT subscriptions are made without an enabled MQTT config entry."""
+    hass.config.components.add("mqtt")
+    mock_config_entry.add_to_hass(hass)
+    with patch("homeassistant.components.mqtt.async_subscribe") as mock_subscribe:
+        await hass.config_entries.async_setup(mock_config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    mock_subscribe.assert_not_called()
+    assert hass.states.get("switch.amazon_fire_screensaver")
+
+
 def has_subscribed(mqtt_mock: MqttMockHAClient, topic: str) -> bool:
     """Check if MQTT topic has subscription."""
     for call in mqtt_mock.async_subscribe.call_args_list: