# Core Development **URL:** https://discuss.python.org/c/core-dev/23.md [Latest](https://discuss.python.org/latest.md) · [Categories](https://discuss.python.org/categories.md) · [Tags](https://discuss.python.org/tags.md) --- ## [About the Core Development category](https://discuss.python.org/t/about-the-core-development-category/3628)
**Author:** [@brettcannon](https://discuss.python.org/u/brettcannon)\ **Replies:** 0\ **Last updated:** [March 3, 2020, 11:51pm UTC](https://discuss.python.org/t/about-the-core-development-category/3628 "2020-03-03T23:51:09Z")
Discussions relating to the development of Python (usage of Python should be discussed in the Python Help category, new ideas for Python to Ideas ). --- ## [Free-threaded GC improvements](https://discuss.python.org/t/free-threaded-gc-improvements/109530)
**Author:** [@thomas](https://discuss.python.org/u/thomas)\ **Replies:** 1\ **Last updated:** [October 17, 2026, 1:05pm UTC](https://discuss.python.org/t/free-threaded-gc-improvements/109530 "2026-10-17T13:05:01Z")
I’ve been spending a little time investigating potential improvements to the free-threaded GC, using Claude Code to prototype and measure the effects. None of the code is in a state that I would be eager to merge into CP… --- ## [Python on Windows ARM64](https://discuss.python.org/t/python-on-windows-arm64/104524)
**Author:** [@steve.dower](https://discuss.python.org/u/steve.dower)\ **Replies:** 29\ **Last updated:** [October 16, 2026, 4:51pm UTC](https://discuss.python.org/t/python-on-windows-arm64/104524 "2026-10-16T16:51:58Z")
Those who read all the way through release pages will have noticed that we’ve had “experimental” releases for Windows ARM64 platforms. These have been stable since about 3.10, but it’s taken a while for the ecosystem to … --- ## [PEP 845: Leading-Dot Value Patterns for match statement](https://discuss.python.org/t/pep-845-leading-dot-value-patterns-for-match-statement/109405)
**Author:** [@stoneleaf](https://discuss.python.org/u/stoneleaf)\ **Replies:** 16\ **Last updated:** [October 16, 2026, 2:13am UTC](https://discuss.python.org/t/pep-845-leading-dot-value-patterns-for-match-statement/109405 "2026-10-16T02:13:05Z")
Continuing the discussion from PEP 845: Leading-Dot Value Patterns: Please chime in with your thoughts! --- ## [Review request for PR #151479: clarify pathlib full\_match docs](https://discuss.python.org/t/review-request-for-pr-151479-clarify-pathlib-full-match-docs/109484)
**Author:** [@harjothkhara](https://discuss.python.org/u/harjothkhara)\ **Replies:** 2\ **Last updated:** [October 15, 2026, 8:01pm UTC](https://discuss.python.org/t/review-request-for-pr-151479-clarify-pathlib-full-match-docs/109484 "2026-10-15T20:01:57Z")
Hi, I’d appreciate a review of PR #151479, a small documentation-only change that adds an example to the pathlib full\_match() docs showing how \*\* behaves with trailing slashes. The PR has been open for about four month… --- ## [Rust for CPython Progress Update April 2026](https://discuss.python.org/t/rust-for-cpython-progress-update-april-2026/106895)
**Author:** [@emmatyping](https://discuss.python.org/u/emmatyping)\ **Replies:** 3\ **Last updated:** [October 15, 2026, 2:58am UTC](https://discuss.python.org/t/rust-for-cpython-progress-update-april-2026/106895 "2026-10-15T02:58:03Z")
To head off unfocused discussion, I ask that folks refrain from making this thread a discussion about whether or not Rust should be introduced into CPython. There will be a PEP thread for that later this year! We (the … --- ## [Python 3.16.0 alpha 1 is now available!](https://discuss.python.org/t/python-3-16-0-alpha-1-is-now-available/109466)
**Author:** [@savannahostrowski](https://discuss.python.org/u/savannahostrowski)\ **Replies:** 12\ **Last updated:** [October 14, 2026, 11:14pm UTC](https://discuss.python.org/t/python-3-16-0-alpha-1-is-now-available/109466 "2026-10-14T23:14:26Z")
This is an early developer preview of Python 3.16 What’s new in Python 3.16? There’s plenty still to come in Python 3.16, but its first alpha is ready to try! Python 3.16.0a1 is the first of seven planned alpha releas… --- ## [Review request for #150326](https://discuss.python.org/t/review-request-for-150326/109013)
**Author:** [@edvilme](https://discuss.python.org/u/edvilme)\ **Replies:** 5\ **Last updated:** [October 13, 2026, 11:40pm UTC](https://discuss.python.org/t/review-request-for-150326/109013 "2026-10-13T23:40:33Z")
Hello. I submitted this PR a couple of weeks ago that has not gotten much attention. Who can I ask for a review? gh-150318: Fix \`\`quantiles(method=‘exclusive’)\`\` returning unsorted cut points for duplicate floats by edv… --- ## [Python 3.10.22, 3.11.17, 3.12.15, 3.13.16 and 3.14.8 are now available!](https://discuss.python.org/t/python-3-10-22-3-11-17-3-12-15-3-13-16-and-3-14-8-are-now-available/109296)
**Author:** [@pablogsal](https://discuss.python.org/u/pablogsal)\ **Replies:** 14\ **Last updated:** [October 12, 2026, 5:53am UTC](https://discuss.python.org/t/python-3-10-22-3-11-17-3-12-15-3-13-16-and-3-14-8-are-now-available/109296 "2026-10-12T05:53:52Z")
A full sweep of Python releases is here: Python 3.10.22, 3.11.17, 3.12.15, 3.13.16 and 3.14.8 are now available! One last lap around the Sun for Python 3.10, and security updates across all five series. Get them here: … --- ## [Python 3.15.0 (final) is here!](https://discuss.python.org/t/python-3-15-0-final-is-here/109415)
**Author:** [@hugovk](https://discuss.python.org/u/hugovk)\ **Replies:** 4\ **Last updated:** [October 10, 2026, 3:52am UTC](https://discuss.python.org/t/python-3-15-0-final-is-here/109415 "2026-10-10T03:52:30Z")
Python 3.15.0 is now available python.org/downloads/release/python-3150/ This is the stable release of Python 3.15.0 Python 3.15.0 is the newest major release of the Python programming language, and it contains many… --- ## [Generate \`Modules/getbuildinfo.h\` when building Python to get build information statically](https://discuss.python.org/t/generate-modules-getbuildinfo-h-when-building-python-to-get-build-information-statically/109401)
**Author:** [@vstinner](https://discuss.python.org/u/vstinner)\ **Replies:** 0\ **Last updated:** [October 8, 2026, 4:28pm UTC](https://discuss.python.org/t/generate-modules-getbuildinfo-h-when-building-python-to-get-build-information-statically/109401 "2026-10-08T16:28:42Z")
Hi, In short, please test my PR gh-158951 if you cross-compile Python or build Python in a specific way. The PR changes Python build system to run a new generate\_getbuildinfo.py script which generates getbuildinfo.h fil… --- ## [Python 3.15: following tradition, let's have a surprise rc3!](https://discuss.python.org/t/python-3-15-following-tradition-lets-have-a-surprise-rc3/109313)
**Author:** [@hugovk](https://discuss.python.org/u/hugovk)\ **Replies:** 3\ **Last updated:** [October 2, 2026, 9:09pm UTC](https://discuss.python.org/t/python-3-15-following-tradition-lets-have-a-surprise-rc3/109313 "2026-10-02T21:09:13Z")
Following recent tradition, I’m going to add a surprise third release candidate for Python 3.15.0! We got some last-minute lazy-import release blockers, and it makes sense to include them in 3.15.0 final. It also makes … --- ## [Enabling thread\_inherit\_context and context\_aware\_warnings by default on both builds](https://discuss.python.org/t/enabling-thread-inherit-context-and-context-aware-warnings-by-default-on-both-builds/108205)
**Author:** [@ngoldbaum](https://discuss.python.org/u/ngoldbaum)\ **Replies:** 37\ **Last updated:** [October 7, 2026, 1:04pm UTC](https://discuss.python.org/t/enabling-thread-inherit-context-and-context-aware-warnings-by-default-on-both-builds/108205 "2026-10-07T13:04:14Z")
Currently, context variables and warnings behave differently when used with threads on the free-threaded build and the GIL-enabled build: on the free-threaded build, a new thread inherits the creating thread’s context by… --- ## [Python 3.15.0 candidate 3 is here!](https://discuss.python.org/t/python-3-15-0-candidate-3-is-here/109327)
**Author:** [@hugovk](https://discuss.python.org/u/hugovk)\ **Replies:** 2\ **Last updated:** [October 5, 2026, 11:05pm UTC](https://discuss.python.org/t/python-3-15-0-candidate-3-is-here/109327 "2026-10-05T23:05:20Z")
Following recent tradition, here’s a surprise third release candidate for Python 3.15.0! We got some last-minute lazy-import release blockers, and it makes sense to include them in 3.15.0 final. It also makes sense to g… --- ## [Announcing the Python Language Summit 2026 blog posts](https://discuss.python.org/t/announcing-the-python-language-summit-2026-blog-posts/109284)
**Author:** [@sethmlarson](https://discuss.python.org/u/sethmlarson)\ **Replies:** 1\ **Last updated:** [October 5, 2026, 5:28pm UTC](https://discuss.python.org/t/announcing-the-python-language-summit-2026-blog-posts/109284 "2026-10-05T17:28:53Z")
Hey everyone, the Python Language Summit 2026 blog posts are now available on Python Insider. The Python Language Summit took place on July 14th, 2026, this year held in Kraków, Poland at EuroPython 2026. I hope you enjo… --- ## [Getting exceptions & built-in types using \`Py\_GetConstant\`](https://discuss.python.org/t/getting-exceptions-built-in-types-using-py-getconstant/108861)
**Author:** [@encukou](https://discuss.python.org/u/encukou)\ **Replies:** 5\ **Last updated:** [October 5, 2026, 1:40pm UTC](https://discuss.python.org/t/getting-exceptions-built-in-types-using-py-getconstant/108861 "2026-10-05T13:40:21Z")
I propose defining identifiers for use with Py\_GetConstant for exceptions (e.g. Py\_CONSTANT\_Exc\_ValueError to get ValueError) and other built-in types (e.g. Py\_CONSTANT\_Bool\_Type to get bool). When compiling for Stabl… --- ## [PEP 842 postmortem: how do we protect the standard library?](https://discuss.python.org/t/pep-842-postmortem-how-do-we-protect-the-standard-library/108575)
**Author:** [@ZeroIntensity](https://discuss.python.org/u/ZeroIntensity)\ **Replies:** 55\ **Last updated:** [October 4, 2026, 1:25am UTC](https://discuss.python.org/t/pep-842-postmortem-how-do-we-protect-the-standard-library/108575 "2026-10-04T01:25:45Z")
Hi, I recently wrote a proposal to hide private attributes from modules. My motivation for this was to prevent people from relying on stdlib internals. Now that the PEP has been withdrawn, I still think we need to find … --- ## [Review request for #157590](https://discuss.python.org/t/review-request-for-157590/109331)
**Author:** [@edvilme](https://discuss.python.org/u/edvilme)\ **Replies:** 5\ **Last updated:** [October 3, 2026, 7:57pm UTC](https://discuss.python.org/t/review-request-for-157590/109331 "2026-10-03T19:57:26Z")
Hello, can I please get a review here? gh-157581: can\_colorize should handle unexpected exceptions by edvilme · Pull Request #157590 · python/cpython It catches unhandled exceptions in can\_colorize to avoid overflowing … --- ## [Review request for PR #158315](https://discuss.python.org/t/review-request-for-pr-158315/109338)
**Author:** [@ashm-dev](https://discuss.python.org/u/ashm-dev)\ **Replies:** 0\ **Last updated:** [October 3, 2026, 4:12pm UTC](https://discuss.python.org/t/review-request-for-pr-158315/109338 "2026-10-03T16:12:40Z")
Hello, can I please get a review here? gh-158304: Avoid creating StopIteration for every value yielded by an async generator by ashm-dev · Pull Request #158315 · python/cpython · GitHub --- ## [Remove \_\_author\_\_, \_\_credits\_\_ and \_\_copyright\_\_ from stdlib modules](https://discuss.python.org/t/remove-author-credits-and-copyright-from-stdlib-modules/109199)
**Author:** [@Stanfromireland](https://discuss.python.org/u/Stanfromireland)\ **Replies:** 10\ **Last updated:** [September 30, 2026, 10:11pm UTC](https://discuss.python.org/t/remove-author-credits-and-copyright-from-stdlib-modules/109199 "2026-09-30T22:11:11Z")
Around twenty stdlib modules, including json, io, inspect, and tarfile, still set \_\_author\_\_, \_\_credits\_\_ or \_\_copyright\_\_ attributes, mostly left over from when the modules were first added. $ git grep -E "\_\_(author|cr… --- ## [C API: Migrate embedded Python to PyConfig and PyInitConfig APIs](https://discuss.python.org/t/c-api-migrate-embedded-python-to-pyconfig-and-pyinitconfig-apis/109215)
**Author:** [@vstinner](https://discuss.python.org/u/vstinner)\ **Replies:** 0\ **Last updated:** [September 24, 2026, 4:18pm UTC](https://discuss.python.org/t/c-api-migrate-embedded-python-to-pyconfig-and-pyinitconfig-apis/109215 "2026-09-24T16:18:01Z")
Hi, I removed 21 deprecated global configuration variables and 4 deprecated functions in Python 3.16 C API. If your project embeds Python, it may affected if it doesn’t use PyConfig or PyInitConfig C API yet. I created … --- ## [Compiling CPython fails without wide-char NCurses](https://discuss.python.org/t/compiling-cpython-fails-without-wide-char-ncurses/109209)
**Author:** [@Deepfriedice](https://discuss.python.org/u/Deepfriedice)\ **Replies:** 2\ **Last updated:** [September 24, 2026, 1:19pm UTC](https://discuss.python.org/t/compiling-cpython-fails-without-wide-char-ncurses/109209 "2026-09-24T13:19:58Z")
I’m in the process of yak-shaving, and currently struggling to compile CPython. I’m trying to build NCurses locally without wide character support, and then build CPython that’s linked against that. To use the narrow ve… --- ## [Add \`!R\` conversion to f-string and \`str.format()\` to format error messages](https://discuss.python.org/t/add-r-conversion-to-f-string-and-str-format-to-format-error-messages/109098)
**Author:** [@vstinner](https://discuss.python.org/u/vstinner)\ **Replies:** 10\ **Last updated:** [September 23, 2026, 9:33am UTC](https://discuss.python.org/t/add-r-conversion-to-f-string-and-str-format-to-format-error-messages/109098 "2026-09-23T09:33:08Z")
Hi, I propose adding !R conversion format to f-string to format error messages and quote properly str subclasses. Example: class StrSubclass(str): def \_\_repr\_\_(self): return '\' abc = StrSubclass(… --- ## [What to do with re.LOCALE?](https://discuss.python.org/t/what-to-do-with-re-locale/32600)
**Author:** [@storchaka](https://discuss.python.org/u/storchaka)\ **Replies:** 11\ **Last updated:** [September 21, 2026, 12:47pm UTC](https://discuss.python.org/t/what-to-do-with-re-locale/32600 "2026-09-21T12:47:52Z")
The re.LOCALE flag and the (?L) mode modifier determine what is a letter and what characters are equal in case-insensitive mode in a byte pattern. It only works with byte strings, not Unicode strings. It only works in … --- ## [Deprecate the iterator interface of async generator \`asend\`/\`athrow\` objects](https://discuss.python.org/t/deprecate-the-iterator-interface-of-async-generator-asend-athrow-objects/109137)
**Author:** [@kumaraditya303](https://discuss.python.org/u/kumaraditya303)\ **Replies:** 4\ **Last updated:** [September 19, 2026, 8:04pm UTC](https://discuss.python.org/t/deprecate-the-iterator-interface-of-async-generator-asend-athrow-objects/109137 "2026-09-19T20:04:44Z")
I propose to deprecate \_\_iter\_\_ and \_\_next\_\_ on the async\_generator\_asend and async\_generator\_athrow types, leaving them with \_\_await\_\_, send, throw and close like coroutines as described in PEP 525. The motivation is… --- ## [Review request for PR #151425: document co\_linetable](https://discuss.python.org/t/review-request-for-pr-151425-document-co-linetable/109099)
**Author:** [@harjothkhara](https://discuss.python.org/u/harjothkhara)\ **Replies:** 2\ **Last updated:** [September 19, 2026, 2:59am UTC](https://discuss.python.org/t/review-request-for-pr-151425-document-co-linetable/109099 "2026-09-19T02:59:49Z")
Hi, I’d appreciate a review of PR #151425, a small documentation-only change that adds the currently undocumented code.co\_linetable attribute to the data model reference. The PR has been open for just over three months. … --- ## [Build provenance of openssl-bin-3.5.7 for CPython 3.14.6 on Windows](https://discuss.python.org/t/build-provenance-of-openssl-bin-3-5-7-for-cpython-3-14-6-on-windows/109109)
**Author:** [@168win](https://discuss.python.org/u/168win)\ **Replies:** 1\ **Last updated:** [September 18, 2026, 1:10pm UTC](https://discuss.python.org/t/build-provenance-of-openssl-bin-3-5-7-for-cpython-3-14-6-on-windows/109109 "2026-09-18T13:10:03Z")
Hello, I’m trying to establish the build provenance and configuration of the Windows x64 OpenSSL binaries used by CPython 3.14.6. CPython 3.14.6 selects the openssl-bin-3.5.7 branch from python/cpython-bin-deps. I foun… --- ## [Why keep mimalloc 2.12?](https://discuss.python.org/t/why-keep-mimalloc-2-12/109040)
**Author:** [@clin1234](https://discuss.python.org/u/clin1234)\ **Replies:** 2\ **Last updated:** [September 15, 2026, 3:50pm UTC](https://discuss.python.org/t/why-keep-mimalloc-2-12/109040 "2026-09-15T15:50:44Z")
Right now, the free-threaded interpreter relies on a heavily patched version of mimalloc 2.12. Is there a particular reason why this old version is kept, and why CPython hasn’t migrated to a newer 2.x version (currently … --- ## [Semaphores for use with both threads and asyncio?](https://discuss.python.org/t/semaphores-for-use-with-both-threads-and-asyncio/109055)
**Author:** [@brittanyrey](https://discuss.python.org/u/brittanyrey)\ **Replies:** 4\ **Last updated:** [September 15, 2026, 1:31am UTC](https://discuss.python.org/t/semaphores-for-use-with-both-threads-and-asyncio/109055 "2026-09-15T01:31:38Z")
Hi! I’m currently adopting a program to use FT Python and went down a bit of a rabbit hole. The code bounds a shared resource with a semaphore, acquired from inside an asyncio event loop. With free threading, the code m… --- ## [Supporting Destructors in the TSS API](https://discuss.python.org/t/supporting-destructors-in-the-tss-api/108906)
**Author:** [@davidhewitt](https://discuss.python.org/u/davidhewitt)\ **Replies:** 4\ **Last updated:** [September 14, 2026, 3:12pm UTC](https://discuss.python.org/t/supporting-destructors-in-the-tss-api/108906 "2026-09-14T15:12:36Z")
We have been looking in PyO3 at using the Python Thread-Specific-Storage API to provide thread-local storage for extensions which don’t want to depend on the implementation in the Rust standard library. One feature whic… [Next page](https://discuss.python.org/c/core-dev/23.md?page=1)