Make resource-warning __del__ code safer during shutdown

Author: kristjanvalur

redis/asyncio/client.py

@@ -480,13 +480,18 @@ async def __aexit__(self, exc_type, exc_value, traceback):
 
     _DEL_MESSAGE = "Unclosed Redis client"
 
-    def __del__(self, _warnings: Any = warnings) -> None:
+    # passing _warnings and _grl as argument default since they may be gone
+    # by the time __del__ is called at shutdown
+    def __del__(
+        self, _warn: Any = warnings.warn, _grl: Any = asyncio.get_running_loop
+    ) -> None:
         if hasattr(self, "connection") and (self.connection is not None):
-            _warnings.warn(
-                f"Unclosed client session {self!r}", ResourceWarning, source=self
-            )
-            context = {"client": self, "message": self._DEL_MESSAGE}
-            asyncio.get_running_loop().call_exception_handler(context)
+            _warn(f"Unclosed client session {self!r}", ResourceWarning, source=self)
+            try:
+                context = {"client": self, "message": self._DEL_MESSAGE}
+                _grl().call_exception_handler(context)
+            except RuntimeError:
+                pass
 
     async def close(self, close_connection_pool: Optional[bool] = None) -> None:
         """

redis/asyncio/cluster.py

@@ -418,14 +418,16 @@ def __await__(self) -> Generator[Any, None, "RedisCluster"]:
 
     _DEL_MESSAGE = "Unclosed RedisCluster client"
 
-    def __del__(self) -> None:
+    def __del__(
+        self, _warn: Any = warnings.warn, _grl: Any = asyncio.get_running_loop
+    ) -> None:
         if hasattr(self, "_initialize") and not self._initialize:
-            warnings.warn(f"{self._DEL_MESSAGE} {self!r}", ResourceWarning, source=self)
+            _warn(f"{self._DEL_MESSAGE} {self!r}", ResourceWarning, source=self)
             try:
                 context = {"client": self, "message": self._DEL_MESSAGE}
-                asyncio.get_running_loop().call_exception_handler(context)
+                _grl().call_exception_handler(context)
             except RuntimeError:
-                ...
+                pass
 
     async def on_connect(self, connection: Connection) -> None:
         await connection.on_connect()
@@ -954,17 +956,18 @@ def __eq__(self, obj: Any) -> bool:
 
     _DEL_MESSAGE = "Unclosed ClusterNode object"
 
-    def __del__(self) -> None:
+    def __del__(
+        self, _warn: Any = warnings.warn, _grl: Any = asyncio.get_running_loop
+    ) -> None:
         for connection in self._connections:
             if connection.is_connected:
-                warnings.warn(
-                    f"{self._DEL_MESSAGE} {self!r}", ResourceWarning, source=self
-                )
+                _warn(f"{self._DEL_MESSAGE} {self!r}", ResourceWarning, source=self)
+
                 try:
                     context = {"client": self, "message": self._DEL_MESSAGE}
-                    asyncio.get_running_loop().call_exception_handler(context)
+                    _grl().call_exception_handler(context)
                 except RuntimeError:
-                    ...
+                    pass
                 break
 
     async def disconnect(self) -> None: