Make Riemann sum sensors restore last valid state (#93674)

* keep last valid state

* keep last valid state

* typo

* increase coverage

* better error handling

* debug messages

* increase coverage

* remove random log

* don't expose last_valid_state as an attribute

homeassistant/components/integration/sensor.py

@@ -1,16 +1,19 @@
 """Numeric integration of data coming from a source sensor over time."""
 from __future__ import annotations
 
-from decimal import Decimal, DecimalException
+from dataclasses import dataclass
+from decimal import Decimal, DecimalException, InvalidOperation
 import logging
-from typing import Final
+from typing import Any, Final
 
+from typing_extensions import Self
 import voluptuous as vol
 
 from homeassistant.components.sensor import (
     PLATFORM_SCHEMA,
+    RestoreSensor,
     SensorDeviceClass,
-    SensorEntity,
+    SensorExtraStoredData,
     SensorStateClass,
 )
 from homeassistant.config_entries import ConfigEntry
@@ -28,7 +31,6 @@ from homeassistant.core import Event, HomeAssistant, State, callback
 from homeassistant.helpers import config_validation as cv, entity_registry as er
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.event import async_track_state_change_event
-from homeassistant.helpers.restore_state import RestoreEntity
 from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
 
 from .const import (
@@ -79,6 +81,53 @@ PLATFORM_SCHEMA = vol.All(
 )
 
 
+@dataclass
+class IntegrationSensorExtraStoredData(SensorExtraStoredData):
+    """Object to hold extra stored data."""
+
+    source_entity: str | None
+    last_valid_state: Decimal | None
+
+    def as_dict(self) -> dict[str, Any]:
+        """Return a dict representation of the utility sensor data."""
+        data = super().as_dict()
+        data["source_entity"] = self.source_entity
+        data["last_valid_state"] = (
+            str(self.last_valid_state) if self.last_valid_state else None
+        )
+        return data
+
+    @classmethod
+    def from_dict(cls, restored: dict[str, Any]) -> Self | None:
+        """Initialize a stored sensor state from a dict."""
+        extra = SensorExtraStoredData.from_dict(restored)
+        if extra is None:
+            return None
+
+        source_entity = restored.get(ATTR_SOURCE_ID)
+
+        try:
+            last_valid_state = (
+                Decimal(str(restored.get("last_valid_state")))
+                if restored.get("last_valid_state")
+                else None
+            )
+        except InvalidOperation:
+            # last_period is corrupted
+            _LOGGER.error("Could not use last_valid_state")
+            return None
+
+        if last_valid_state is None:
+            return None
+
+        return cls(
+            extra.native_value,
+            extra.native_unit_of_measurement,
+            source_entity,
+            last_valid_state,
+        )
+
+
 async def async_setup_entry(
     hass: HomeAssistant,
     config_entry: ConfigEntry,
@@ -129,7 +178,7 @@ async def async_setup_platform(
 
 
 # pylint: disable-next=hass-invalid-inheritance # needs fixing
-class IntegrationSensor(RestoreEntity, SensorEntity):
+class IntegrationSensor(RestoreSensor):
     """Representation of an integration sensor."""
 
     _attr_state_class = SensorStateClass.TOTAL
@@ -160,7 +209,8 @@ class IntegrationSensor(RestoreEntity, SensorEntity):
         self._unit_time = UNIT_TIME[unit_time]
         self._unit_time_str = unit_time
         self._attr_icon = "mdi:chart-histogram"
-        self._attr_extra_state_attributes = {ATTR_SOURCE_ID: source_entity}
+        self._source_entity: str = source_entity
+        self._last_valid_state: Decimal | None = None
 
     def _unit(self, source_unit: str) -> str:
         """Derive unit from the source sensor, SI prefix and time unit."""
@@ -175,10 +225,28 @@ 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()) is not None:
+
+        if (last_sensor_data := await self.async_get_last_sensor_data()) is not None:
+            self._state = (
+                Decimal(str(last_sensor_data.native_value))
+                if last_sensor_data.native_value
+                else last_sensor_data.last_valid_state
+            )
+            self._attr_native_value = last_sensor_data.native_value
+            self._unit_of_measurement = last_sensor_data.native_unit_of_measurement
+            self._last_valid_state = last_sensor_data.last_valid_state
+
+            _LOGGER.debug(
+                "Restored state %s and last_valid_state %s",
+                self._state,
+                self._last_valid_state,
+            )
+        elif (state := await self.async_get_last_state()) is not None:
+            # legacy to be removed on 2023.10 (we are keeping this to avoid losing data during the transition)
+            if state.state in [STATE_UNAVAILABLE, STATE_UNKNOWN]:
                 if state.state == STATE_UNAVAILABLE:
                     self._attr_available = False
-            elif state.state != STATE_UNKNOWN:
+            else:
                 try:
                     self._state = Decimal(state.state)
                 except (DecimalException, ValueError) as err:
@@ -295,6 +363,7 @@ class IntegrationSensor(RestoreEntity, SensorEntity):
                     self._state += integral
                 else:
                     self._state = integral
+                self._last_valid_state = self._state
                 self.async_write_ha_state()
 
         self.async_on_remove(
@@ -314,3 +383,33 @@ class IntegrationSensor(RestoreEntity, SensorEntity):
     def native_unit_of_measurement(self) -> str | None:
         """Return the unit the value is expressed in."""
         return self._unit_of_measurement
+
+    @property
+    def extra_state_attributes(self) -> dict[str, str] | None:
+        """Return the state attributes of the sensor."""
+        state_attr = {
+            ATTR_SOURCE_ID: self._source_entity,
+        }
+
+        return state_attr
+
+    @property
+    def extra_restore_state_data(self) -> IntegrationSensorExtraStoredData:
+        """Return sensor specific state data to be restored."""
+        return IntegrationSensorExtraStoredData(
+            self.native_value,
+            self.native_unit_of_measurement,
+            self._source_entity,
+            self._last_valid_state,
+        )
+
+    async def async_get_last_sensor_data(
+        self,
+    ) -> IntegrationSensorExtraStoredData | None:
+        """Restore Utility Meter Sensor Extra Stored Data."""
+        if (restored_last_extra_data := await self.async_get_last_extra_data()) is None:
+            return None
+
+        return IntegrationSensorExtraStoredData.from_dict(
+            restored_last_extra_data.as_dict()
+        )

tests/components/integration/test_sensor.py

@@ -19,7 +19,7 @@ from homeassistant.core import HomeAssistant, State
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
 
-from tests.common import mock_restore_cache
+from tests.common import mock_restore_cache, mock_restore_cache_with_extra_data
 
 
 @pytest.mark.parametrize("method", ["trapezoidal", "left", "right"])
@@ -163,6 +163,100 @@ async def test_restore_state(hass: HomeAssistant) -> None:
     assert state.state == "100.00"
     assert state.attributes.get("unit_of_measurement") == UnitOfEnergy.KILO_WATT_HOUR
     assert state.attributes.get("device_class") == SensorDeviceClass.ENERGY
+    assert state.attributes.get("last_good_state") is None
+
+
+async def test_restore_unavailable_state(hass: HomeAssistant) -> None:
+    """Test integration sensor state is restored correctly."""
+    mock_restore_cache_with_extra_data(
+        hass,
+        [
+            (
+                State(
+                    "sensor.integration",
+                    STATE_UNAVAILABLE,
+                    {
+                        "device_class": SensorDeviceClass.ENERGY,
+                        "unit_of_measurement": UnitOfEnergy.KILO_WATT_HOUR,
+                    },
+                ),
+                {
+                    "native_value": None,
+                    "native_unit_of_measurement": "kWh",
+                    "source_entity": "sensor.power",
+                    "last_valid_state": "100.00",
+                },
+            ),
+        ],
+    )
+    config = {
+        "sensor": {
+            "platform": "integration",
+            "name": "integration",
+            "source": "sensor.power",
+            "round": 2,
+        }
+    }
+
+    assert await async_setup_component(hass, "sensor", config)
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.integration")
+    assert state
+    assert state.state == "100.00"
+
+
+@pytest.mark.parametrize(
+    "extra_attributes",
+    [
+        {
+            "native_unit_of_measurement": "kWh",
+            "source_entity": "sensor.power",
+            "last_valid_state": "100.00",
+        },
+        {
+            "native_value": None,
+            "native_unit_of_measurement": "kWh",
+            "source_entity": "sensor.power",
+            "last_valid_state": "None",
+        },
+    ],
+)
+async def test_restore_unavailable_state_failed(
+    hass: HomeAssistant, extra_attributes
+) -> None:
+    """Test integration sensor state is restored correctly."""
+    mock_restore_cache_with_extra_data(
+        hass,
+        [
+            (
+                State(
+                    "sensor.integration",
+                    STATE_UNAVAILABLE,
+                    {
+                        "device_class": SensorDeviceClass.ENERGY,
+                        "unit_of_measurement": UnitOfEnergy.KILO_WATT_HOUR,
+                    },
+                ),
+                extra_attributes,
+            ),
+        ],
+    )
+    config = {
+        "sensor": {
+            "platform": "integration",
+            "name": "integration",
+            "source": "sensor.power",
+            "round": 2,
+        }
+    }
+
+    assert await async_setup_component(hass, "sensor", config)
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.integration")
+    assert state
+    assert state.state == STATE_UNAVAILABLE
 
 
 async def test_restore_state_failed(hass: HomeAssistant) -> None: