Fix yeelight brightness when nightlight switch is disabled (#55278)

homeassistant/components/yeelight/light.py

@@ -859,7 +859,12 @@ class YeelightColorLightWithoutNightlightSwitch(
 
     @property
     def _brightness_property(self):
-        return "current_brightness"
+        # If the nightlight is not active, we do not
+        # want to "current_brightness" since it will check
+        # "bg_power" and main light could still be on
+        if self.device.is_nightlight_enabled:
+            return "current_brightness"
+        return super()._brightness_property
 
 
 class YeelightColorLightWithNightlightSwitch(
@@ -883,7 +888,12 @@ class YeelightWhiteTempWithoutNightlightSwitch(
 
     @property
     def _brightness_property(self):
-        return "current_brightness"
+        # If the nightlight is not active, we do not
+        # want to "current_brightness" since it will check
+        # "bg_power" and main light could still be on
+        if self.device.is_nightlight_enabled:
+            return "current_brightness"
+        return super()._brightness_property
 
 
 class YeelightWithNightLight(

tests/components/yeelight/test_light.py

@@ -96,6 +96,7 @@ from homeassistant.util.color import (
 )
 
 from . import (
+    CAPABILITIES,
     ENTITY_LIGHT,
     ENTITY_NIGHTLIGHT,
     IP_ADDRESS,
@@ -1178,3 +1179,38 @@ async def test_state_fails_to_update_triggers_update(hass: HomeAssistant):
     )
     assert len(mocked_bulb.async_turn_on.mock_calls) == 1
     assert len(mocked_bulb.async_get_properties.mock_calls) == 3
+
+
+async def test_ambilight_with_nightlight_disabled(hass: HomeAssistant):
+    """Test that main light on ambilights with the nightlight disabled shows the correct brightness."""
+    mocked_bulb = _mocked_bulb()
+    properties = {**PROPERTIES}
+    capabilities = {**CAPABILITIES}
+    capabilities["model"] = "ceiling10"
+    properties["color_mode"] = "3"  # HSV
+    properties["bg_power"] = "off"
+    properties["current_brightness"] = 0
+    properties["bg_lmode"] = "2"  # CT
+    mocked_bulb.last_properties = properties
+    mocked_bulb.bulb_type = BulbType.WhiteTempMood
+    main_light_entity_id = "light.yeelight_ceiling10_0x15243f"
+
+    config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={**CONFIG_ENTRY_DATA, CONF_NIGHTLIGHT_SWITCH: False},
+        options={**CONFIG_ENTRY_DATA, CONF_NIGHTLIGHT_SWITCH: False},
+    )
+    config_entry.add_to_hass(hass)
+    with _patch_discovery(capabilities=capabilities), patch(
+        f"{MODULE}.AsyncBulb", return_value=mocked_bulb
+    ):
+        assert await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+        # We use asyncio.create_task now to avoid
+        # blocking starting so we need to block again
+        await hass.async_block_till_done()
+
+    state = hass.states.get(main_light_entity_id)
+    assert state.state == "on"
+    # bg_power off should not set the brightness to 0
+    assert state.attributes[ATTR_BRIGHTNESS] == 128