Remove legacy fallback in light color_mode property

homeassistant/components/light/__init__.py

@@ -779,7 +779,7 @@ class LightEntity(ToggleEntity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
 
     entity_description: LightEntityDescription
     _attr_brightness: int | None = None
-    _attr_color_mode: ColorMode | None = None
+    _attr_color_mode: ColorMode = ColorMode.UNKNOWN
     _attr_color_temp_kelvin: int | None = None
     _attr_effect_list: list[str] | None = None
     _attr_effect: str | None = None
@@ -801,43 +801,10 @@ def brightness(self) -> int | None:
         return self._attr_brightness
 
     @cached_property
-    def color_mode(self) -> ColorMode | None:
+    def color_mode(self) -> ColorMode:
         """Return the color mode of the light."""
         return self._attr_color_mode
 
-    @property
-    def _light_internal_color_mode(self) -> str:
-        """Return the color mode of the light with backwards compatibility."""
-        if (color_mode := self.color_mode) is None:
-            # Backwards compatibility for color_mode added in 2021.4
-            # Warning added in 2024.3, break in 2025.3
-            if not self.__color_mode_reported and self.__should_report_light_issue():
-                self.__color_mode_reported = True
-                report_issue = self._suggest_report_issue()
-                _LOGGER.warning(
-                    (
-                        "%s (%s) does not report a color mode, this will stop working "
-                        "in Home Assistant Core 2025.3, please %s"
-                    ),
-                    self.entity_id,
-                    type(self),
-                    report_issue,
-                )
-
-            supported = self._light_internal_supported_color_modes
-
-            if ColorMode.HS in supported and self.hs_color is not None:
-                return ColorMode.HS
-            if ColorMode.COLOR_TEMP in supported and self.color_temp_kelvin is not None:
-                return ColorMode.COLOR_TEMP
-            if ColorMode.BRIGHTNESS in supported and self.brightness is not None:
-                return ColorMode.BRIGHTNESS
-            if ColorMode.ONOFF in supported:
-                return ColorMode.ONOFF
-            return ColorMode.UNKNOWN
-
-        return color_mode
-
     @cached_property
     def hs_color(self) -> tuple[float, float] | None:
         """Return the hue and saturation color value [float, float]."""
@@ -1084,7 +1051,7 @@ def state_attributes(self) -> dict[str, Any] | None:
         )
 
         _is_on = self.is_on
-        color_mode = self._light_internal_color_mode if _is_on else None
+        color_mode = self.color_mode if _is_on else None
 
         effect: str | None
         if LightEntityFeature.EFFECT in supported_features:

pylint/plugins/hass_enforce_type_hints.py

@@ -1837,7 +1837,7 @@ class ClassTypeHintMatch:
                 ),
                 TypeHintMatch(
                     function_name="color_mode",
-                    return_type=["ColorMode", None],
+                    return_type=["ColorMode"],
                     mandatory=True,
                 ),
                 TypeHintMatch(

tests/components/light/test_init.py

@@ -2379,36 +2379,6 @@ def test_filter_supported_color_modes() -> None:
     assert light.filter_supported_color_modes(supported) == {light.ColorMode.BRIGHTNESS}
 
 
-@pytest.mark.parametrize(
-    ("color_mode", "supported_color_modes", "warning_expected"),
-    [
-        (None, {light.ColorMode.ONOFF}, True),
-        (light.ColorMode.ONOFF, {light.ColorMode.ONOFF}, False),
-    ],
-)
-async def test_report_no_color_mode(
-    hass: HomeAssistant,
-    caplog: pytest.LogCaptureFixture,
-    color_mode: str,
-    supported_color_modes: set[str],
-    warning_expected: bool,
-) -> None:
-    """Test a light setting no color mode."""
-
-    class MockLightEntityEntity(light.LightEntity):
-        _attr_color_mode = color_mode
-        _attr_is_on = True
-        _attr_supported_features = light.LightEntityFeature.EFFECT
-        _attr_supported_color_modes = supported_color_modes
-
-    entity = MockLightEntityEntity()
-    platform = MockEntityPlatform(hass, domain="test", platform_name="test")
-    await platform.async_add_entities([entity])
-    entity._async_calculate_state()
-    expected_warning = "does not report a color mode"
-    assert (expected_warning in caplog.text) is warning_expected
-
-
 @pytest.mark.parametrize(
     ("color_mode", "supported_color_modes", "warning_expected"),
     [