gh-100348: Fix ref cycle in asyncio._SelectorSocketTransport with _read_ready_cb (#100349)

Author: rkojedzinszky

Lib/asyncio/selector_events.py

@@ -1133,6 +1133,10 @@ def _make_empty_waiter(self):
     def _reset_empty_waiter(self):
         self._empty_waiter = None
 
+    def close(self):
+        self._read_ready_cb = None
+        super().close()
+
 
 class _SelectorDatagramTransport(_SelectorTransport, transports.DatagramTransport):
 

Misc/NEWS.d/next/Library/2022-12-19-19-30-06.gh-issue-100348.o7IAHh.rst

@@ -0,0 +1,2 @@
+Fix ref cycle in :class:`!asyncio._SelectorSocketTransport` by removing ``_read_ready_cb`` in ``close``.
+