Add ClassVar annotation for singleton patterns (#134135)

homeassistant/components/cast/helpers.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 import configparser
 from dataclasses import dataclass
 import logging
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, ClassVar
 from urllib.parse import urlparse
 
 import aiohttp
@@ -129,7 +129,7 @@ class ChromecastInfo:
 class ChromeCastZeroconf:
     """Class to hold a zeroconf instance."""
 
-    __zconf: zeroconf.HaZeroconf | None = None
+    __zconf: ClassVar[zeroconf.HaZeroconf | None] = None
 
     @classmethod
     def set_zeroconf(cls, zconf: zeroconf.HaZeroconf) -> None:

homeassistant/components/yeelight/scanner.py

@@ -9,7 +9,7 @@ from datetime import datetime
 from functools import partial
 from ipaddress import IPv4Address
 import logging
-from typing import Self
+from typing import ClassVar, Self
 from urllib.parse import urlparse
 
 from async_upnp_client.search import SsdpSearchListener
@@ -44,11 +44,11 @@ def _set_future_if_not_done(future: asyncio.Future[None]) -> None:
 class YeelightScanner:
     """Scan for Yeelight devices."""
 
-    _scanner: Self | None = None
+    _scanner: ClassVar[Self | None] = None
 
     @classmethod
     @callback
-    def async_get(cls, hass: HomeAssistant) -> YeelightScanner:
+    def async_get(cls, hass: HomeAssistant) -> Self:
         """Get scanner instance."""
         if cls._scanner is None:
             cls._scanner = cls(hass)