Don't try to restore unavailable nor unknown states (#92825)

homeassistant/components/integration/sensor.py

@@ -174,23 +174,23 @@ class IntegrationSensor(RestoreEntity, SensorEntity):
     async def async_added_to_hass(self) -> None:
         """Handle entity which will be added."""
         await super().async_added_to_hass()
-        if state := await self.async_get_last_state():
-            try:
-                self._state = Decimal(state.state)
-            except (DecimalException, ValueError) as err:
-                _LOGGER.warning(
-                    "%s could not restore last state %s: %s",
-                    self.entity_id,
-                    state.state,
-                    err,
-                )
-            else:
-                self._attr_device_class = state.attributes.get(ATTR_DEVICE_CLASS)
-                if self._unit_of_measurement is None:
-                    self._unit_of_measurement = state.attributes.get(
-                        ATTR_UNIT_OF_MEASUREMENT
+        if (state := await self.async_get_last_state()) is not None:
+            if state.state == STATE_UNAVAILABLE:
+                self._attr_available = False
+            elif state.state != STATE_UNKNOWN:
+                try:
+                    self._state = Decimal(state.state)
+                except (DecimalException, ValueError) as err:
+                    _LOGGER.warning(
+                        "%s could not restore last state %s: %s",
+                        self.entity_id,
+                        state.state,
+                        err,
                     )
 
+            self._attr_device_class = state.attributes.get(ATTR_DEVICE_CLASS)
+            self._unit_of_measurement = state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
+
         @callback
         def calc_integration(event: Event) -> None:
             """Handle the sensor state changes."""