Fix ESPHome alarm_control_panel when state is missing (#95871)

homeassistant/components/esphome/alarm_control_panel.py

@@ -33,6 +33,7 @@ from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
 from .entity import (
     EsphomeEntity,
+    esphome_state_property,
     platform_async_setup_entry,
 )
 from .enum_mapper import EsphomeEnumMapper
@@ -111,6 +112,7 @@ class EsphomeAlarmControlPanel(
         self._attr_code_arm_required = bool(static_info.requires_code_to_arm)
 
     @property
+    @esphome_state_property
     def state(self) -> str | None:
         """Return the state of the device."""
         return _ESPHOME_ACP_STATE_TO_HASS_STATE.from_esphome(self._state.state)

tests/components/esphome/test_alarm_control_panel.py

@@ -24,6 +24,7 @@ from homeassistant.components.esphome.alarm_control_panel import EspHomeACPFeatu
 from homeassistant.const import (
     ATTR_ENTITY_ID,
     STATE_ALARM_ARMED_AWAY,
+    STATE_UNKNOWN,
 )
 from homeassistant.core import HomeAssistant
 
@@ -209,3 +210,38 @@ async def test_generic_alarm_control_panel_no_code(
         [call(1, AlarmControlPanelCommand.DISARM, None)]
     )
     mock_client.alarm_control_panel_command.reset_mock()
+
+
+async def test_generic_alarm_control_panel_missing_state(
+    hass: HomeAssistant,
+    mock_client: APIClient,
+    mock_generic_device_entry,
+) -> None:
+    """Test a generic alarm_control_panel entity that is missing state."""
+    entity_info = [
+        AlarmControlPanelInfo(
+            object_id="myalarm_control_panel",
+            key=1,
+            name="my alarm_control_panel",
+            unique_id="my_alarm_control_panel",
+            supported_features=EspHomeACPFeatures.ARM_AWAY
+            | EspHomeACPFeatures.ARM_CUSTOM_BYPASS
+            | EspHomeACPFeatures.ARM_HOME
+            | EspHomeACPFeatures.ARM_NIGHT
+            | EspHomeACPFeatures.ARM_VACATION
+            | EspHomeACPFeatures.TRIGGER,
+            requires_code=False,
+            requires_code_to_arm=False,
+        )
+    ]
+    states = []
+    user_service = []
+    await mock_generic_device_entry(
+        mock_client=mock_client,
+        entity_info=entity_info,
+        user_service=user_service,
+        states=states,
+    )
+    state = hass.states.get("alarm_control_panel.test_my_alarm_control_panel")
+    assert state is not None
+    assert state.state == STATE_UNKNOWN