Fix Roborock number entity crash when volume is None

The volume number entity called float() directly on the trait value,
raising a TypeError when the device reports no volume (None). Return
None in that case so the entity reports an unknown state instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015muhdayAokSd8W9u2QYVJk

homeassistant/components/roborock/number.py

@@ -35,7 +35,7 @@ class RoborockNumberDescription(NumberEntityDescription):
     trait: Callable[[PropertiesApi], Any | None]
     """Function to determine if number entity is supported by the device."""
 
-    get_value: Callable[[Any], float]
+    get_value: Callable[[Any], float | None]
     """Function to get the value from the trait."""
 
     set_value: Callable[[Any, float], Coroutine[Any, Any, None]]
@@ -51,7 +51,9 @@ NUMBER_DESCRIPTIONS: list[RoborockNumberDescription] = [
         native_unit_of_measurement=PERCENTAGE,
         entity_category=EntityCategory.CONFIG,
         trait=lambda api: api.sound_volume,
-        get_value=lambda trait: float(trait.volume),
+        get_value=lambda trait: (
+            float(trait.volume) if trait.volume is not None else None
+        ),
         set_value=lambda trait, value: trait.set_volume(int(value)),
     )
 ]

tests/components/roborock/test_number.py

@@ -4,9 +4,10 @@ import pytest
 from roborock.exceptions import RoborockTimeout
 
 from homeassistant.components.number import ATTR_VALUE, SERVICE_SET_VALUE
-from homeassistant.const import Platform
+from homeassistant.const import STATE_UNKNOWN, Platform
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import HomeAssistantError
+from homeassistant.helpers.entity_component import async_update_entity
 
 from .conftest import FakeDevice
 
@@ -49,6 +50,22 @@ async def test_update_sound_volume(
     assert state.state == "3.0"
 
 
+async def test_volume_unknown_value(
+    hass: HomeAssistant,
+    setup_entry: MockConfigEntry,
+    fake_vacuum: FakeDevice,
+) -> None:
+    """Test the entity reports unknown when the trait value is None."""
+    assert fake_vacuum.v1_properties is not None
+    fake_vacuum.v1_properties.sound_volume.volume = None
+
+    await async_update_entity(hass, "number.roborock_s7_maxv_volume")
+
+    state = hass.states.get("number.roborock_s7_maxv_volume")
+    assert state is not None
+    assert state.state == STATE_UNKNOWN
+
+
 async def test_volume_update_failed(
     hass: HomeAssistant,
     setup_entry: MockConfigEntry,