gh-73458: Fix logging.config.listen() on a host without an IPv4 address#154491
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serhiy-storchaka merged 2 commits intoJul 24, 2026
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… address The server is created in a thread which set the "ready" event only after a successful start, so a failure to start left the caller waiting for that event forever. Set it also on failure. The receiver always used AF_INET, which fails if the host has no IPv4 address, for example if "localhost" is only aliased to ::1. Use the family of the first resolved address in such case. Also fixes pythongh-82076. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Like the other logging.config.listen() tests. It failed on WASI and Emscripten, which cannot start a thread. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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needs backport to 3.13
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Thank you very much for this, Serhiy.
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Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14, 3.15. |
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GH-154616 is a backport of this pull request to the 3.15 branch. |
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GH-154617 is a backport of this pull request to the 3.14 branch. |
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GH-154618 is a backport of this pull request to the 3.13 branch. |
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…4 address (GH-154491) (GH-154618) The server is created in a thread which set the "ready" event only after a successful start, so a failure to start left the caller waiting for that event forever. Set it also on failure. The receiver always used AF_INET, which fails if the host has no IPv4 address, for example if "localhost" is only aliased to ::1. Use the family of the first resolved address in such case. Also fixes gh-82076. (cherry picked from commit 45a10f5) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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…4 address (GH-154491) (GH-154617) The server is created in a thread which set the "ready" event only after a successful start, so a failure to start left the caller waiting for that event forever. Set it also on failure. The receiver always used AF_INET, which fails if the host has no IPv4 address, for example if "localhost" is only aliased to ::1. Use the family of the first resolved address in such case. Also fixes gh-82076. (cherry picked from commit 45a10f5) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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logging.config.listen()cannot be used on a host without an IPv4 address, and any failure to start the server leaves the caller waiting forever.The server is created in a thread which set the
readyevent only after a successful start, so if the receiver could not be constructed, the thread died andt.ready.wait()blocked forever. This is the hang reported in gh-73458 and gh-82076. It happens for any failure to start, not only on IPv6 hosts: an invalid or already used port hangs the caller too.ConfigSocketReceiveralso inheritedaddress_family = AF_INETfromThreadingTCPServerwhile binding the namelocalhost, so the bind fails iflocalhosthas no IPv4 address. The family is now taken from the resolved address, but only when there is no IPv4 address, so dual-stack hosts keep binding IPv4 as before. Resolution errors are left to the server, so an invalid port still reports the same exception as before.Verified by patching
socket.getaddrinfo()so thatlocalhostresolves only to::1: before the change the client getsConnectionRefusedError, after it the connection is made overAF_INET6and the configuration is delivered. With ports-1,65536,99999,'http','nosuchservice',Noneand1.5the raised exception types are unchanged; only the hang is gone.The test no longer forces
AF_INETwhen connecting, and the waits forreadynow have a timeout, so a regression fails instead of hanging.🤖 Generated with Claude Code