Ensure it's safe to call Entity.__repr__ on non added entity (#106032)

homeassistant/components/sensor/__init__.py

@@ -734,17 +734,6 @@ class SensorEntity(Entity, cached_properties=CACHED_PROPERTIES_WITH_ATTR_):
 
         return value
 
-    def __repr__(self) -> str:
-        """Return the representation.
-
-        Entity.__repr__ includes the state in the generated string, this fails if we're
-        called before self.hass is set.
-        """
-        if not self.hass:
-            return f"<Entity {self.name}>"
-
-        return super().__repr__()
-
     def _suggested_precision_or_none(self) -> int | None:
         """Return suggested display precision, or None if not set."""
         assert self.registry_entry

homeassistant/helpers/entity.py

@@ -1476,7 +1476,12 @@ class Entity(
             self.async_on_remove(self._async_unsubscribe_device_updates)
 
     def __repr__(self) -> str:
-        """Return the representation."""
+        """Return the representation.
+
+        If the entity is not added to a platform it's not safe to call _stringify_state.
+        """
+        if self._platform_state != EntityPlatformState.ADDED:
+            return f"<entity {self.entity_id}={STATE_UNKNOWN}>"
         return f"<entity {self.entity_id}={self._stringify_state(self.available)}>"
 
     async def async_request_call(self, coro: Coroutine[Any, Any, _T]) -> _T:

tests/helpers/test_entity.py

@@ -1392,8 +1392,8 @@ async def test_translation_key(hass: HomeAssistant) -> None:
     assert mock_entity2.translation_key == "from_entity_description"
 
 
-async def test_repr_using_stringify_state() -> None:
-    """Test that repr uses stringify state."""
+async def test_repr(hass) -> None:
+    """Test Entity.__repr__."""
 
     class MyEntity(MockEntity):
         """Mock entity."""
@@ -1403,9 +1403,20 @@ async def test_repr_using_stringify_state() -> None:
             """Return the state."""
             raise ValueError("Boom")
 
+    platform = MockEntityPlatform(hass, domain="hello")
     my_entity = MyEntity(entity_id="test.test", available=False)
+
+    # Not yet added
+    assert str(my_entity) == "<entity test.test=unknown>"
+
+    # Added
+    await platform.async_add_entities([my_entity])
     assert str(my_entity) == "<entity test.test=unavailable>"
 
+    # Removed
+    await platform.async_remove_entity(my_entity.entity_id)
+    assert str(my_entity) == "<entity test.test=unknown>"
+
 
 async def test_warn_using_async_update_ha_state(
     hass: HomeAssistant, caplog: pytest.LogCaptureFixture