Cleanup if discovered mqtt alarm can't be added (#19742)

* Cleanup if discovered mqtt alarm can't be added

homeassistant/components/alarm_control_panel/mqtt.py

@@ -21,7 +21,8 @@ from homeassistant.components.mqtt import (
     CONF_PAYLOAD_AVAILABLE, CONF_PAYLOAD_NOT_AVAILABLE, CONF_QOS, CONF_RETAIN,
     CONF_STATE_TOPIC, MqttAvailability, MqttDiscoveryUpdate,
     MqttEntityDeviceInfo, subscription)
-from homeassistant.components.mqtt.discovery import MQTT_DISCOVERY_NEW
+from homeassistant.components.mqtt.discovery import (
+    MQTT_DISCOVERY_NEW, clear_discovery_hash)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
 from homeassistant.helpers.typing import HomeAssistantType, ConfigType
@@ -62,9 +63,15 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
     """Set up MQTT alarm control panel dynamically through MQTT discovery."""
     async def async_discover(discovery_payload):
         """Discover and add an MQTT alarm control panel."""
-        config = PLATFORM_SCHEMA(discovery_payload)
-        await _async_setup_entity(config, async_add_entities,
-                                  discovery_payload[ATTR_DISCOVERY_HASH])
+        try:
+            discovery_hash = discovery_payload[ATTR_DISCOVERY_HASH]
+            config = PLATFORM_SCHEMA(discovery_payload)
+            await _async_setup_entity(config, async_add_entities,
+                                      discovery_hash)
+        except Exception:
+            if discovery_hash:
+                clear_discovery_hash(hass, discovery_hash)
+            raise
 
     async_dispatcher_connect(
         hass, MQTT_DISCOVERY_NEW.format(alarm.DOMAIN, 'mqtt'),

tests/components/alarm_control_panel/test_mqtt.py

@@ -300,7 +300,7 @@ async def test_discovery_removal_alarm(hass, mqtt_mock, caplog):
 
 
 async def test_discovery_update_alarm(hass, mqtt_mock, caplog):
-    """Test removal of discovered alarm_control_panel."""
+    """Test update of discovered alarm_control_panel."""
     entry = MockConfigEntry(domain=mqtt.DOMAIN)
     await async_start(hass, 'homeassistant', {}, entry)
 
@@ -338,6 +338,41 @@ async def test_discovery_update_alarm(hass, mqtt_mock, caplog):
     assert state is None
 
 
+async def test_discovery_broken(hass, mqtt_mock, caplog):
+    """Test handling of bad discovery message."""
+    entry = MockConfigEntry(domain=mqtt.DOMAIN)
+    await async_start(hass, 'homeassistant', {}, entry)
+
+    data1 = (
+        '{ "name": "Beer" }'
+    )
+    data2 = (
+        '{ "name": "Milk",'
+        '  "status_topic": "test_topic",'
+        '  "command_topic": "test_topic" }'
+    )
+
+    async_fire_mqtt_message(hass,
+                            'homeassistant/alarm_control_panel/bla/config',
+                            data1)
+    await hass.async_block_till_done()
+
+    state = hass.states.get('alarm_control_panel.beer')
+    assert state is None
+
+    async_fire_mqtt_message(hass,
+                            'homeassistant/alarm_control_panel/bla/config',
+                            data2)
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+
+    state = hass.states.get('alarm_control_panel.milk')
+    assert state is not None
+    assert state.name == 'Milk'
+    state = hass.states.get('alarm_control_panel.beer')
+    assert state is None
+
+
 async def test_entity_device_info_with_identifier(hass, mqtt_mock):
     """Test MQTT alarm control panel device registry integration."""
     entry = MockConfigEntry(domain=mqtt.DOMAIN)