Python: Asyncio Stability and Exception Handling Fixes
Today's CPython activity centers on reliability during failure paths — a use-after-free in async task cleanup, leaked references after failed TLS handshakes, and skipped exception handlers in loops. The compiler fix and asyncio backports to 3.14 and 3.15 carry the highest developer impact.
Duration: PT2M10S
Episode overview
This episode is a short developer briefing from Python.
It explains recent repository work in plain language.
- Show: Python
- Published: 2026-10-19T13:13:06Z
- Audio duration: PT2M10S
Transcript excerpt
This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.
Hello, today is October 19th, 2026, and this is your Python briefing.
The throughline today is cleanup that must happen even when things fail — in async shutdown, in TLS errors, and in loops interrupted by exceptions.
First, async I O hardening. Pull request 159073 centralizes transfer of remaining async tasks to the interpreter during thread state cleanup, fixing a use-after-free that could corrupt memory during shutdown. It is now backported to the 3.14 and 3.15 branches. Related work in pull request 159140 fixes reference…
Second, a compiler correctness fix with real safety implications. Pull request 159460 addresses missing exception handlers for backward jumps at the end of loops. Previously, if a loop ended in a conditional branch back to the loop head, that jump could sit outside the exception table. An interruption there — like a…
Finally, proposals to watch. An open fix for the process pool executor would detect when a worker is killed mid-result and fail the future instead of hanging shutdown. Another proposal reworks Windows directory removal to use extended-length paths to handle very long nested paths, and a small core optimization skips…
Expect stable-branch validation…
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