Make derivative sensor unavailable when source sensor is unavailable (#147468)

homeassistant/components/derivative/sensor.py

@@ -198,6 +198,7 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
         self._attr_native_value = round(Decimal(0), round_digits)
         # List of tuples with (timestamp_start, timestamp_end, derivative)
         self._state_list: list[tuple[datetime, datetime, Decimal]] = []
+        self._last_valid_state_time: tuple[str, datetime] | None = None
 
         self._attr_name = name if name is not None else f"{source_entity} derivative"
         self._attr_extra_state_attributes = {ATTR_SOURCE_ID: source_entity}
@@ -242,6 +243,25 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
             if (current_time - time_end).total_seconds() < self._time_window
         ]
 
+    def _handle_invalid_source_state(self, state: State | None) -> bool:
+        # Check the source state for unknown/unavailable condition. If unusable, write unknown/unavailable state and return false.
+        if not state or state.state == STATE_UNAVAILABLE:
+            self._attr_available = False
+            self.async_write_ha_state()
+            return False
+        if not _is_decimal_state(state.state):
+            self._attr_available = True
+            self._write_native_value(None)
+            return False
+        self._attr_available = True
+        return True
+
+    def _write_native_value(self, derivative: Decimal | None) -> None:
+        self._attr_native_value = (
+            None if derivative is None else round(derivative, self._round_digits)
+        )
+        self.async_write_ha_state()
+
     async def async_added_to_hass(self) -> None:
         """Handle entity which will be added."""
         await super().async_added_to_hass()
@@ -255,8 +275,8 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
                     Decimal(restored_data.native_value),  # type: ignore[arg-type]
                     self._round_digits,
                 )
-            except SyntaxError as err:
-                _LOGGER.warning("Could not restore last state: %s", err)
+            except (InvalidOperation, TypeError):
+                self._attr_native_value = None
 
         def schedule_max_sub_interval_exceeded(source_state: State | None) -> None:
             """Schedule calculation using the source state and max_sub_interval.
@@ -280,9 +300,7 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
 
                     self._prune_state_list(now)
                     derivative = self._calc_derivative_from_state_list(now)
-                    self._attr_native_value = round(derivative, self._round_digits)
-
-                    self.async_write_ha_state()
+                    self._write_native_value(derivative)
 
                     # If derivative is now zero, don't schedule another timeout callback, as it will have no effect
                     if derivative != 0:
@@ -299,36 +317,46 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
             """Handle constant sensor state."""
             self._cancel_max_sub_interval_exceeded_callback()
             new_state = event.data["new_state"]
+            if not self._handle_invalid_source_state(new_state):
+                return
+
+            assert new_state
             if self._attr_native_value == Decimal(0):
                 # If the derivative is zero, and the source sensor hasn't
                 # changed state, then we know it will still be zero.
                 return
             schedule_max_sub_interval_exceeded(new_state)
-            new_state = event.data["new_state"]
-            if new_state is not None:
-                calc_derivative(
-                    new_state, new_state.state, event.data["old_last_reported"]
-                )
+            calc_derivative(new_state, new_state.state, event.data["old_last_reported"])
 
         @callback
         def on_state_changed(event: Event[EventStateChangedData]) -> None:
             """Handle changed sensor state."""
             self._cancel_max_sub_interval_exceeded_callback()
             new_state = event.data["new_state"]
+            if not self._handle_invalid_source_state(new_state):
+                return
+
+            assert new_state
             schedule_max_sub_interval_exceeded(new_state)
             old_state = event.data["old_state"]
-            if new_state is not None and old_state is not None:
+            if old_state is not None:
                 calc_derivative(new_state, old_state.state, old_state.last_reported)
+            else:
+                # On first state change from none, update availability
+                self.async_write_ha_state()
 
         def calc_derivative(
             new_state: State, old_value: str, old_last_reported: datetime
         ) -> None:
             """Handle the sensor state changes."""
-            if old_value in (STATE_UNKNOWN, STATE_UNAVAILABLE) or new_state.state in (
-                STATE_UNKNOWN,
-                STATE_UNAVAILABLE,
-            ):
-                return
+            if not _is_decimal_state(old_value):
+                if self._last_valid_state_time:
+                    old_value = self._last_valid_state_time[0]
+                    old_last_reported = self._last_valid_state_time[1]
+                else:
+                    # Sensor becomes valid for the first time, just keep the restored value
+                    self.async_write_ha_state()
+                    return
 
             if self.native_unit_of_measurement is None:
                 unit = new_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
@@ -373,6 +401,10 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
             self._state_list.append(
                 (old_last_reported, new_state.last_reported, new_derivative)
             )
+            self._last_valid_state_time = (
+                new_state.state,
+                new_state.last_reported,
+            )
 
             # If outside of time window just report derivative (is the same as modeling it in the window),
             # otherwise take the weighted average with the previous derivatives
@@ -382,11 +414,16 @@ class DerivativeSensor(RestoreSensor, SensorEntity):
                 derivative = self._calc_derivative_from_state_list(
                     new_state.last_reported
                 )
-            self._attr_native_value = round(derivative, self._round_digits)
-            self.async_write_ha_state()
+            self._write_native_value(derivative)
+
+        source_state = self.hass.states.get(self._sensor_source_id)
+        if source_state is None or source_state.state in [
+            STATE_UNAVAILABLE,
+            STATE_UNKNOWN,
+        ]:
+            self._attr_available = False
 
         if self._max_sub_interval is not None:
-            source_state = self.hass.states.get(self._sensor_source_id)
             schedule_max_sub_interval_exceeded(source_state)
 
             @callback

tests/components/derivative/test_init.py

@@ -99,6 +99,9 @@ async def test_setup_and_remove_config_entry(
     input_sensor_entity_id = "sensor.input"
     derivative_entity_id = "sensor.my_derivative"
 
+    hass.states.async_set(input_sensor_entity_id, "10.0", {})
+    await hass.async_block_till_done()
+
     # Setup the config entry
     config_entry = MockConfigEntry(
         data={},

tests/components/derivative/test_sensor.py

@@ -6,16 +6,26 @@ import random
 from typing import Any
 
 from freezegun import freeze_time
+import pytest
 
 from homeassistant.components.derivative.const import DOMAIN
 from homeassistant.components.sensor import ATTR_STATE_CLASS, SensorStateClass
-from homeassistant.const import STATE_UNAVAILABLE, UnitOfPower, UnitOfTime
+from homeassistant.const import (
+    STATE_UNAVAILABLE,
+    STATE_UNKNOWN,
+    UnitOfPower,
+    UnitOfTime,
+)
 from homeassistant.core import HomeAssistant, State
 from homeassistant.helpers import device_registry as dr, entity_registry as er
 from homeassistant.setup import async_setup_component
 from homeassistant.util import dt as dt_util
 
-from tests.common import MockConfigEntry, async_fire_time_changed
+from tests.common import (
+    MockConfigEntry,
+    async_fire_time_changed,
+    mock_restore_cache_with_extra_data,
+)
 
 
 async def test_state(hass: HomeAssistant) -> None:
@@ -106,6 +116,7 @@ async def _setup_sensor(
 
     config = {"sensor": dict(default_config, **config)}
     assert await async_setup_component(hass, "sensor", config)
+    await hass.async_block_till_done()
 
     entity_id = config["sensor"]["source"]
     hass.states.async_set(entity_id, 0, {})
@@ -440,16 +451,14 @@ async def test_sub_intervals_instantaneous(hass: HomeAssistant) -> None:
         await hass.async_block_till_done()
 
         state = hass.states.get("sensor.power")
-        derivative = round(float(state.state), config["sensor"]["round"])
-        assert derivative == -0.29
+        assert state.state == STATE_UNAVAILABLE
 
         now += timedelta(seconds=60)
         async_fire_time_changed(hass, now)
         await hass.async_block_till_done()
 
         state = hass.states.get("sensor.power")
-        derivative = round(float(state.state), config["sensor"]["round"])
-        assert derivative == -0.29
+        assert state.state == STATE_UNAVAILABLE
 
         now += timedelta(seconds=10)
         freezer.move_to(now)
@@ -458,7 +467,7 @@ async def test_sub_intervals_instantaneous(hass: HomeAssistant) -> None:
 
         state = hass.states.get("sensor.power")
         derivative = round(float(state.state), config["sensor"]["round"])
-        assert derivative == -0.29
+        assert derivative == 0
 
         now += timedelta(seconds=max_sub_interval + 1)
         async_fire_time_changed(hass, now)
@@ -693,3 +702,148 @@ async def test_device_id(
     derivative_entity = entity_registry.async_get("sensor.derivative")
     assert derivative_entity is not None
     assert derivative_entity.device_id == source_entity.device_id
+
+
+@pytest.mark.parametrize("bad_state", [STATE_UNAVAILABLE, STATE_UNKNOWN, "foo"])
+async def test_unavailable(
+    bad_state: str,
+    hass: HomeAssistant,
+) -> None:
+    """Test derivative sensor state when unavailable."""
+    config, entity_id = await _setup_sensor(hass, {"unit_time": "s"})
+
+    times = [0, 1, 2, 3]
+    values = [0, 1, bad_state, 2]
+    expected_state = [
+        0,
+        1,
+        STATE_UNAVAILABLE if bad_state == STATE_UNAVAILABLE else STATE_UNKNOWN,
+        0.5,
+    ]
+
+    # Testing a energy sensor with non-monotonic intervals and values
+    base = dt_util.utcnow()
+    with freeze_time(base) as freezer:
+        for time, value, expect in zip(times, values, expected_state, strict=False):
+            freezer.move_to(base + timedelta(seconds=time))
+            hass.states.async_set(entity_id, value, {})
+            await hass.async_block_till_done()
+
+            state = hass.states.get("sensor.power")
+            assert state is not None
+            rounded_state = (
+                state.state
+                if expect in [STATE_UNKNOWN, STATE_UNAVAILABLE]
+                else round(float(state.state), config["sensor"]["round"])
+            )
+            assert rounded_state == expect
+
+
+@pytest.mark.parametrize("bad_state", [STATE_UNAVAILABLE, STATE_UNKNOWN, "foo"])
+async def test_unavailable_2(
+    bad_state: str,
+    hass: HomeAssistant,
+) -> None:
+    """Test derivative sensor state when unavailable with a time window."""
+    config, entity_id = await _setup_sensor(
+        hass, {"unit_time": "s", "time_window": {"seconds": 10}}
+    )
+
+    # Monotonically increasing by 1, with some unavailable holes
+    times = list(range(21))
+    values = list(range(21))
+    values[3] = bad_state
+    values[6] = bad_state
+    values[7] = bad_state
+    values[8] = bad_state
+
+    base = dt_util.utcnow()
+    with freeze_time(base) as freezer:
+        for time, value in zip(times, values, strict=False):
+            freezer.move_to(base + timedelta(seconds=time))
+            hass.states.async_set(entity_id, value, {})
+            await hass.async_block_till_done()
+
+            state = hass.states.get("sensor.power")
+            assert state is not None
+
+            if value == bad_state:
+                assert (
+                    state.state == STATE_UNAVAILABLE
+                    if bad_state is STATE_UNAVAILABLE
+                    else STATE_UNKNOWN
+                )
+            else:
+                expect = (time / 10) if time < 10 else 1
+                assert round(float(state.state), config["sensor"]["round"]) == round(
+                    expect, config["sensor"]["round"]
+                )
+
+
+@pytest.mark.parametrize("restore_state", ["3.00", STATE_UNKNOWN])
+async def test_unavailable_boot(
+    restore_state,
+    hass: HomeAssistant,
+) -> None:
+    """Test that the booting sequence does not leave derivative in a bad state."""
+
+    mock_restore_cache_with_extra_data(
+        hass,
+        [
+            (
+                State(
+                    "sensor.power",
+                    restore_state,
+                    {
+                        "unit_of_measurement": "W",
+                    },
+                ),
+                {
+                    "native_value": restore_state,
+                    "native_unit_of_measurement": "W",
+                },
+            ),
+        ],
+    )
+
+    config = {
+        "platform": "derivative",
+        "name": "power",
+        "source": "sensor.energy",
+        "round": 2,
+        "unit_time": "s",
+    }
+
+    config = {"sensor": config}
+    entity_id = config["sensor"]["source"]
+    hass.states.async_set(entity_id, STATE_UNAVAILABLE, {})
+    await hass.async_block_till_done()
+
+    assert await async_setup_component(hass, "sensor", config)
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.power")
+    assert state is not None
+    # Sensor is unavailable as source is unavailable
+    assert state.state == STATE_UNAVAILABLE
+
+    base = dt_util.utcnow()
+    with freeze_time(base) as freezer:
+        freezer.move_to(base + timedelta(seconds=1))
+        hass.states.async_set(entity_id, 10, {})
+        await hass.async_block_till_done()
+
+        state = hass.states.get("sensor.power")
+        assert state is not None
+        # The source sensor has moved to a valid value, but we need 2 points to derive,
+        # so just hold until the next tick
+        assert state.state == restore_state
+
+        freezer.move_to(base + timedelta(seconds=2))
+        hass.states.async_set(entity_id, 15, {})
+        await hass.async_block_till_done()
+
+        state = hass.states.get("sensor.power")
+        assert state is not None
+        # Now that the source sensor has two valid datapoints, we can calculate derivative
+        assert state.state == "5.00"