[asvetlov]

setsockopt(TCP_NODELAY) can fail on an accepted socket, especially on macOS (EINVAL for a connection already reset by the peer). The failure happens after the transport has registered itself with the loop and the server, leaving a zombie transport behind.

TCP_NODELAY is only a latency optimization and doesn't change the transport's behavior, so _set_nodelay() now ignores OSError.

🤖 Generated with Claude Code

• Issue: asyncio: a failure in setsockopt(TCP_NODELAY) during transport creation leaves a zombie transport, so the fd is poisoned and Server.wait_closed() hangs #161076

[OsmnvAslan]

Thanks for the quick fix! I checked it against main with a reproducer that makes the real setsockopt(TCP_NODELAY) fail once for an accepted socket (rather than patching _set_nodelay()). On main the server is left with a zombie transport: later connections on the same fd fail and wait_closed() hangs. With this PR all three connections are served and wait_closed() returns. LGTM.

[miss-islington-app]

Thanks @asvetlov for the PR, and @kumaraditya303 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.15.
🐍🍒⛏🤖

[miss-islington-app]

Thanks @asvetlov for the PR, and @kumaraditya303 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

[bedevere-app]

GH-161301 is a backport of this pull request to the 3.15 branch.

[bedevere-app]

GH-161302 is a backport of this pull request to the 3.14 branch.

[asvetlov]

Thanks, @kumaraditya303

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 CentOS9 NoGIL Refleaks 3.15 (tier-1) has failed when building commit b2247bb.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/2078/builds/604) and take a look at the build logs.
4. Check if the failure is related to this commit (b2247bb) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/2078/builds/604

Failed tests:

• test.test_concurrent_futures.test_interpreter_pool

Summary of the results of the build (if available):

==

Click to see traceback logs

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Traceback (most recent\ncall last):"; (2


TracebackException instances from exception\nobjects, or the constructor to create TracebackException instances from\nindividual components.\n\n- :attr:`__cause__` A TracebackException of the original *__cause__*.\n- :attr:`__context__` A TracebackException of the original *__context__*.\n- :attr:`exceptions` For exception groups - a list of TracebackException\n  instances for the nested *exceptions*.  ``None`` for other exceptions.\n- :attr:`__suppress_context__` The *__suppress_context__* value from the\n  original exception.\n- :attr:`stack` A `StackSummary` representing the traceback.\n- :attr:`exc_type` (deprecated) The class of the original traceback.\n- :attr:`exc_type_str` String display of exc_type\n- :attr:`filename` For syntax errors - the filename where the error\n  occurred.\n- :attr:`lineno` For syntax errors - the linenumber where the error\n  occurred.\n- :attr:`end_lineno` For syntax errors - the end linenumber where the error\n  occurred. Can be `None` if not present.\n- :attr:`text` For syntax errors - the text where the error\n  occurred.\n- :attr:`offset` For syntax errors - the offset into the text where the\n  error occurred.\n- :attr:`end_offset` For syntax errors - the end offset into the text where\n  the error occurred. Can be `None` if not present.\n- :attr:`msg` For syntax errors - the compiler error message.\n": "An exception ready for rendering.\n\nThe traceback module captures enough attributes from the original exception\nto this intermediary form to ensure that no references are held, while\nstill being able to fully print or format it.\n\nmax_group_width and max_group_depth control the formatting of exception\ngroups. The depth refers to the nesting level of the group, and the width\nrefers to the size of a single exception group's exceptions array. The\nformatted output is truncated when either limit is exceeded.\n\nUse `from_exception` to create TracebackException instances from exception\nobjects, or the constructor to create TracebackException instances from\nindividual components.\n\n- :attr:`__cause__` A TracebackException of the original *__cause__*.\n- :attr:`__context__` A TracebackException of the original *__context__*.\n- :attr:`exceptions` For exception groups - a list of TracebackException\n  instances for the nested *exceptions*.  ``None`` for other exceptions.\n- :attr:`__suppress_context__` The *__suppress_context__* value from the\n  original exception.\n- :attr:`stack` A `StackSummary` representing the traceback.\n- :attr:`exc_type` (deprecated) The class of the original traceback.\n- :attr:`exc_type_str` String display of exc_type\n- :attr:`filename` For syntax errors - the filename where the error\n  occurred.\n- :attr:`lineno` For syntax errors - the linenumber where the error\n  occurred.\n- :attr:`end_lineno` For syntax errors - the end linenumber where the error\n  occurred. Can be `None` if not present.\n- :attr:`text` For syntax errors - the text where the error\n  occurred.\n- :attr:`off

[asvetlov]

The failure is not related to the PR