Skip to content

gh-155305: Preserve user-provided sockets on transport errors #155341

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
RealBhupesh wants to merge 2 commits into
base: main
Choose a base branch
from
+45 −10
Open

gh-155305: Preserve user-provided sockets on transport errors #155341

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
633b4ed
gh-155305: Preserve user-provided sockets on transport errors
RealBhupesh Aug 7, 2026
68b960e
gh-155305: Add asyncio socket ownership NEWS entry
RealBhupesh Aug 7, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 11 additions & 5 deletions Lib/asyncio/base_events.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1083,6 +1083,7 @@ async def create_connection(
connection in the background. When successful, the coroutine
returns a (transport, protocol) pair.
"""
sock_was_provided = sock is not None
if server_hostname is not None and not ssl:
raise ValueError('server_hostname is only meaningful with ssl')

Expand Down Expand Up @@ -1204,7 +1205,8 @@ async def create_connection(
transport, protocol = await self._create_connection_transport(
sock, protocol_factory, ssl, server_hostname,
ssl_handshake_timeout=ssl_handshake_timeout,
ssl_shutdown_timeout=ssl_shutdown_timeout)
ssl_shutdown_timeout=ssl_shutdown_timeout,
sock_was_provided=sock_was_provided)
if self._debug:
# Get the socket from the transport because SSL transport closes
# the old socket and creates a new SSL socket
Expand All @@ -1217,7 +1219,8 @@ async def _create_connection_transport(
self, sock, protocol_factory, ssl,
server_hostname, server_side=False,
ssl_handshake_timeout=None,
ssl_shutdown_timeout=None, context=None):
ssl_shutdown_timeout=None, context=None,
sock_was_provided=False):

try:
sock.setblocking(False)
Expand All @@ -1236,8 +1239,10 @@ async def _create_connection_transport(
else:
transport = self._make_socket_transport(sock, protocol, waiter, context=context)
except:
# gh-153133: close the socket if the transport is never created.
sock.close()
# gh-153133: close internally created sockets if the transport is
# never created.
if not sock_was_provided:
sock.close()
Comment on lines +1244 to +1245

@chatgpt-codex-connector chatgpt-codex-connector Bot Aug 7, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

P2 Badge Restore caller sockets' blocking mode on failure

When a caller supplies a blocking socket and protocol_factory() or transport construction raises, this branch now leaves the socket open even though _create_connection_transport() has already changed it to nonblocking at line 1226 (and create_unix_connection() does so before calling this helper). Because no transport was created and ownership remains with the caller, subsequent ordinary socket operations can unexpectedly raise BlockingIOError; preserve and restore the socket's original timeout/blocking state on this failure path.

Useful? React with 👍 / 👎.

raise

try:
Expand Down Expand Up @@ -1705,7 +1710,8 @@ async def connect_accepted_socket(
transport, protocol = await self._create_connection_transport(
sock, protocol_factory, ssl, '', server_side=True,
ssl_handshake_timeout=ssl_handshake_timeout,
ssl_shutdown_timeout=ssl_shutdown_timeout)
ssl_shutdown_timeout=ssl_shutdown_timeout,
sock_was_provided=True)
if self._debug:
# Get the socket from the transport because SSL transport closes
# the old socket and creates a new SSL socket
Expand Down
4 changes: 3 additions & 1 deletion Lib/asyncio/unix_events.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -227,6 +227,7 @@ async def create_unix_connection(
server_hostname=None,
ssl_handshake_timeout=None,
ssl_shutdown_timeout=None):
sock_was_provided = sock is not None
assert server_hostname is None or isinstance(server_hostname, str)
if ssl:
if server_hostname is None:
Expand Down Expand Up @@ -268,7 +269,8 @@ async def create_unix_connection(
transport, protocol = await self._create_connection_transport(
sock, protocol_factory, ssl, server_hostname,
ssl_handshake_timeout=ssl_handshake_timeout,
ssl_shutdown_timeout=ssl_shutdown_timeout)
ssl_shutdown_timeout=ssl_shutdown_timeout,
sock_was_provided=sock_was_provided)
return transport, protocol

async def create_unix_server(
Expand Down
8 changes: 4 additions & 4 deletions Lib/test/test_asyncio/test_base_events.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1341,9 +1341,9 @@ def getaddrinfo(*args, **kw):
self.loop.run_until_complete(coro)
self.assertTrue(sock.close.called)

def test_create_connection_sock_transport_error_closes_sock(self):
# gh-153133: a user-provided socket is closed if the transport is
# never created.
def test_create_connection_sock_transport_error_does_not_close_sock(self):
# gh-155305: a user-provided socket remains owned by the caller when
# the transport is never created.
sock = mock.Mock()
sock.type = socket.SOCK_STREAM

Expand All @@ -1353,7 +1353,7 @@ def factory():
coro = self.loop.create_connection(factory, sock=sock)
with self.assertRaises(ZeroDivisionError):
self.loop.run_until_complete(coro)
self.assertTrue(sock.close.called)
self.assertFalse(sock.close.called)

@patch_socket
def test_create_connection_transport_error_closes_sock(self, m_socket):
Expand Down
12 changes: 12 additions & 0 deletions Lib/test/test_asyncio/test_events.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -914,6 +914,18 @@ def test_connect_accepted_socket_ssl_timeout_for_plain_socket(self):
'ssl_handshake_timeout is only meaningful with ssl'):
self.loop.run_until_complete(coro)

def test_connect_accepted_socket_transport_error_does_not_close_sock(self):
sock = mock.Mock()
sock.type = socket.SOCK_STREAM

def factory():
raise ZeroDivisionError

coro = self.loop.connect_accepted_socket(factory, sock)
with self.assertRaises(ZeroDivisionError):
self.loop.run_until_complete(coro)
self.assertFalse(sock.close.called)

@mock.patch('asyncio.base_events.socket')
def create_server_multiple_hosts(self, family, hosts, mock_sock):
async def getaddrinfo(host, port, *args, **kw):
Expand Down
13 changes: 13 additions & 0 deletions Lib/test/test_asyncio/test_unix_events.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -393,6 +393,19 @@ def test_create_unix_connection_path_inetsock(self):
'A UNIX Domain Stream.*was expected'):
self.loop.run_until_complete(coro)

def test_create_unix_connection_transport_error_does_not_close_sock(self):
sock = mock.Mock()
sock.family = socket.AF_UNIX
sock.type = socket.SOCK_STREAM

def factory():
raise ZeroDivisionError

coro = self.loop.create_unix_connection(factory, sock=sock)
with self.assertRaises(ZeroDivisionError):
self.loop.run_until_complete(coro)
self.assertFalse(sock.close.called)

@mock.patch('asyncio.unix_events.socket')
def test_create_unix_server_bind_error(self, m_socket):
# Ensure that the socket is closed on any bind error
Expand Down
2 changes: 2 additions & 0 deletions ...d/next/Library/2026-08-07-00-00-00.gh-issue-155305.asyncio-socket-ownership.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
:mod:`asyncio` now preserves user-provided sockets when transport creation
fails in connection helpers.
Loading