From 587feb19e8f9c967e6f88ecd85eca962a57d5410 Mon Sep 17 00:00:00 2001
From: Victor Stinner <victor.stinner@gmail.com>
Date: Fri, 9 Jan 2015 21:34:27 +0100
Subject: [PATCH] Issue #23209: Break some reference cycles in asyncio. Patch
 written by Martin Richard.

---
 Lib/asyncio/base_subprocess.py | 1 +
 Lib/asyncio/futures.py         | 2 +-
 Lib/selectors.py               | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Lib/asyncio/base_subprocess.py b/Lib/asyncio/base_subprocess.py
index 81698b09850..afc434defa2 100644
--- a/Lib/asyncio/base_subprocess.py
+++ b/Lib/asyncio/base_subprocess.py
@@ -182,6 +182,7 @@ class WriteSubprocessPipeProto(protocols.BaseProtocol):
     def connection_lost(self, exc):
         self.disconnected = True
         self.proc._pipe_connection_lost(self.fd, exc)
+        self.proc = None
 
     def pause_writing(self):
         self.proc._protocol.pause_writing()
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index e0e12f0579b..19212a94b9f 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -405,5 +405,5 @@ def wrap_future(fut, *, loop=None):
     new_future.add_done_callback(_check_cancel_other)
     fut.add_done_callback(
         lambda future: loop.call_soon_threadsafe(
-            new_future._copy_state, fut))
+            new_future._copy_state, future))
     return new_future
diff --git a/Lib/selectors.py b/Lib/selectors.py
index e4ad4cb18c4..b2f4c2bad22 100644
--- a/Lib/selectors.py
+++ b/Lib/selectors.py
@@ -256,6 +256,7 @@ class _BaseSelectorImpl(BaseSelector):
 
     def close(self):
         self._fd_to_key.clear()
+        self._map = None
 
     def get_map(self):
         return self._map