Python: Free-Threading Hardening and iOS Builds
Free-threading stability dominates this cycle, with fixes for stop-the-world starvation and weak-reference races, alongside new iOS build options and standard library reliability fixes. Backports to 3.14 and 3.15 account for much of the merged activity.
Duration: PT2M21S
Episode overview
This episode is a short developer briefing from Python.
It explains recent repository work in plain language.
- Show: Python
- Published: 2026-10-14T13:15:02Z
- Audio duration: PT2M21S
Transcript excerpt
This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.
Good morning, it's October 14th, 2026. You're listening to Python.
The lead story is free-threaded reliability. A cluster of changes tightens up thread attach, teardown, and shared interpreter state.
First, stop-the-world handling. Pull request 158186, now backported, fixes starvation where a tight loop of pauses could repeatedly suspend a thread trying to reattach after sleeping and prevent it from returning — an issue found during intentional G-C stress on many-core machines. Follow-up 159372 makes the resume…
Second, platforms: mobile and WebAssembly. Pull request 159386 adds support for free-threaded and debug builds on iOS by turning the checked-in testbed project into a template with build flags. Complementing that, 155222 adds runtime checks for dup-three and pipe-two availability on iOS. And 159039 implements sys…
Third, standard library correctness. Backports 159365 and follow-ons fix a crash when an OS scan-directory iterator is shared between threads. Merged 157915 adds support in OS read link for file descriptors pointing to symlinks. Merged 159156 fixes HTTP client hangs on Content-Length headers with trailing whitespace…
What's next: if you run the free-threaded build,…
Nearby episodes from Python
- Free-Threading Fixes and GC Speedups
- Free-Threading Races, Core Speedups, and Stdlib Hardening
- Free-Threading Crash Fixes and Cleanup Guarantees
- Deterministic Pyc Files and Threading Hardening
- Reproducible Marshal Output and Runtime Speedups
- Weekly Recap - Thread Safety, GC Efficiency and Platform Polish
- Garbage Collector Speedups and Thread-Safety Fixes
- IDLE Reliability Push and WASM Trampoline