From 9d09efa1dcc3096cc6b746dd602524b37883cd8f Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 18:04:51 +0100
Subject: [PATCH 1/4] add test for happy eyeballs refcycles

---
 Lib/test/test_asyncio/test_streams.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py
index d32b7ff251885d..0688299447d064 100644
--- a/Lib/test/test_asyncio/test_streams.py
+++ b/Lib/test/test_asyncio/test_streams.py
@@ -1200,6 +1200,24 @@ async def handle_echo(reader, writer):
         messages = self._basetest_unhandled_exceptions(handle_echo)
         self.assertEqual(messages, [])
 
+    def test_open_connection_happy_eyeball_refcycles(self):
+        port = socket_helper.find_unused_port()
+        async def main():
+            exc = None
+            try:
+                await asyncio.open_connection(
+                    host="localhost",
+                    port=port,
+                    happy_eyeballs_delay=0.25,
+                )
+            except* OSError as excs:
+                # can't use assertRaises because that clears frames
+                exc = excs.exceptions[0]
+            self.assertIsNotNone(exc)
+            self.assertListEqual(gc.get_referrers(exc), [])
+
+        asyncio.run(main())
+
 
 if __name__ == '__main__':
     unittest.main()

From d029782e2fe4c895e4412cbeba71c300cfae9e05 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 18:05:12 +0100
Subject: [PATCH 2/4] fix happy eyeballs refcycles

---
 Lib/asyncio/base_events.py | 18 ++++++++++++------
 Lib/asyncio/staggered.py   |  1 +
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
index 000647f57dd9e3..5dbe4b28d236d3 100644
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -17,7 +17,6 @@
 import collections.abc
 import concurrent.futures
 import errno
-import functools
 import heapq
 import itertools
 import os
@@ -1140,11 +1139,18 @@ async def create_connection(
                     except OSError:
                         continue
             else:  # using happy eyeballs
-                sock, _, _ = await staggered.staggered_race(
-                    (functools.partial(self._connect_sock,
-                                       exceptions, addrinfo, laddr_infos)
-                     for addrinfo in infos),
-                    happy_eyeballs_delay, loop=self)
+                sock = (await staggered.staggered_race(
+                    (
+                        # can't use functools.partial as it keeps a reference
+                        # to exceptions
+                        lambda addrinfo=addrinfo: self._connect_sock(
+                            exceptions, addrinfo, laddr_infos
+                        )
+                        for addrinfo in infos
+                    ),
+                    happy_eyeballs_delay,
+                    loop=self,
+                ))[0]  # can't use sock, _, _ as it keeks a reference to exceptions
 
             if sock is None:
                 exceptions = [exc for sub in exceptions for exc in sub]
diff --git a/Lib/asyncio/staggered.py b/Lib/asyncio/staggered.py
index c3a7441a7b091d..326c6f708944af 100644
--- a/Lib/asyncio/staggered.py
+++ b/Lib/asyncio/staggered.py
@@ -133,6 +133,7 @@ async def run_one_coro(previous_failed) -> None:
                         raise d.exception()
         return winner_result, winner_index, exceptions
     finally:
+        del exceptions
         # Make sure no tasks are left running if we leave this function
         for t in running_tasks:
             t.cancel()

From 9faa31763c34c7a4ec05b7222f3efc0939ef6126 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Tue, 1 Oct 2024 17:12:25 +0000
Subject: [PATCH 3/4] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst  | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst

diff --git a/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst b/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst
new file mode 100644
index 00000000000000..e95f5e9e1b6a75
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst
@@ -0,0 +1 @@
+Fix reference cycles left in tracebacks in asyncio.open_connection when used with happy_eyeballs_delay

From d8f8616624621a395a1fed4b13aad8dd14a2541d Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Wed, 2 Oct 2024 12:57:33 +0100
Subject: [PATCH 4/4] Update
 Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst

---
 .../next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst b/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst
index e95f5e9e1b6a75..c05d24a7c5aacb 100644
--- a/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst
+++ b/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst
@@ -1 +1 @@
-Fix reference cycles left in tracebacks in asyncio.open_connection when used with happy_eyeballs_delay
+Fix reference cycles left in tracebacks in :func:`asyncio.open_connection` when used with ``happy_eyeballs_delay``