# Core Development **URL:** https://discuss.python.org/c/core-dev/23.md?page=1 [Latest](https://discuss.python.org/latest.md) · [Categories](https://discuss.python.org/categories.md) · [Tags](https://discuss.python.org/tags.md) **Page:** 2 --- ## [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 Now that the PEP has been withdrawn, I still think we need to find … --- ## [Review request for #157590](https://discuss.python.org/t/review-request-for-157590/109331)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 --- ## [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… --- ## [Review request for PR #151828](https://discuss.python.org/t/review-request-for-pr-151828/109017)
**Author:** [@harjothkhara](https://discuss.python.org/u/harjothkhara)\ **Replies:** 0\ **Last updated:** [September 11, 2026, 5:38pm UTC](https://discuss.python.org/t/review-request-for-pr-151828/109017 "2026-09-11T17:38:06Z")
Hi, PR #151828 has been open since June 21. It fixes tarfile.open(..., mode="w|gz") raising struct.error when mtime is outside the 32-bit range, matching gzip and RFC 1952’s clamp-to-zero behavior. It includes boundary … --- ## [A benchmark de-noising skill for AI agent to optimize cpython](https://discuss.python.org/t/a-benchmark-de-noising-skill-for-ai-agent-to-optimize-cpython/109001)
**Author:** [@methane](https://discuss.python.org/u/methane)\ **Replies:** 0\ **Last updated:** [September 11, 2026, 8:22am UTC](https://discuss.python.org/t/a-benchmark-de-noising-skill-for-ai-agent-to-optimize-cpython/109001 "2026-09-11T08:22:06Z")
I was using Astra to work on optimizing CPython when the JIT is not enabled. I found several small improvements, and I plan to submit PRs for them. Throughout the optimization work, the instability of pyperformance was … --- ## [New contributor looking for guidance on my first CPython contribution](https://discuss.python.org/t/new-contributor-looking-for-guidance-on-my-first-cpython-contribution/108968)
**Author:** [@MAYANKSHARMA01010](https://discuss.python.org/u/MAYANKSHARMA01010)\ **Replies:** 3\ **Last updated:** [September 9, 2026, 10:46pm UTC](https://discuss.python.org/t/new-contributor-looking-for-guidance-on-my-first-cpython-contribution/108968 "2026-09-09T22:46:15Z")
Hi everyone, I’m a student/developer interested in contributing to CPython and I’d like to start with a beginner-friendly issue. I’m comfortable with Python and Git/GitHub, but I’m new to contributing to CPython itself… --- ## [Review request for Issue #92810](https://discuss.python.org/t/review-request-for-issue-92810/108965)
**Author:** [@dolfinus](https://discuss.python.org/u/dolfinus)\ **Replies:** 0\ **Last updated:** [September 9, 2026, 8:39am UTC](https://discuss.python.org/t/review-request-for-issue-92810/108965 "2026-09-09T08:39:49Z")
There is an issue #92810 - isinstance(ABC\_subclass, ...)/issubclass(ABC\_subclass, ...) can consume gigabytes of RAM if few thousand unlrelated classes are created and compared with each other. There are 4 related PRs: a… --- ## [\[Experimental\] Tracing GC (by Codex)](https://discuss.python.org/t/experimental-tracing-gc-by-codex/108961)
**Author:** [@methane](https://discuss.python.org/u/methane)\ **Replies:** 0\ **Last updated:** [September 9, 2026, 3:07am UTC](https://discuss.python.org/t/experimental-tracing-gc-by-codex/108961 "2026-09-09T03:07:28Z")
I participate in the Codex OSS Program, but I end up with a lot of unused AI credits every week. So I decided to have the latest model explore some ideas that I had been interested in but hadn’t been able to investigate … --- ## [Review request for PR #152984](https://discuss.python.org/t/review-request-for-pr-152984/108918)
**Author:** [@yuanx749](https://discuss.python.org/u/yuanx749)\ **Replies:** 0\ **Last updated:** [September 7, 2026, 8:12am UTC](https://discuss.python.org/t/review-request-for-pr-152984/108918 "2026-09-07T08:12:39Z")
Hi, PR #152984 has been open for more than one month. It fixes a KeyError when passing member names with trailing slashes from getnames() to extract() in tarfile. I’d appreciate a review when someone has time. Thanks! --- ## [Python 3.12.14, 3.11.16 and 3.10.21 are now available!](https://discuss.python.org/t/python-3-12-14-3-11-16-and-3-10-21-are-now-available/108537)
**Author:** [@thomas](https://discuss.python.org/u/thomas)\ **Replies:** 5\ **Last updated:** [September 5, 2026, 11:01am UTC](https://discuss.python.org/t/python-3-12-14-3-11-16-and-3-10-21-are-now-available/108537 "2026-09-05T11:01:53Z")
Python Releases Eclipse Your Security! New security releases for 3.10, 3.11 and 3.12 are now available. (As these Python versions are now in security-fix-only mode, these are source-only releases, and there is no pre-set… --- ## [Isn’t gh-109638 a security problem? Doesn’t it deserve a CVE?](https://discuss.python.org/t/isn-t-gh-109638-a-security-problem-doesn-t-it-deserve-a-cve/108883)
**Author:** [@mcepl](https://discuss.python.org/u/mcepl)\ **Replies:** 4\ **Last updated:** [September 4, 2026, 6:00pm UTC](https://discuss.python.org/t/isn-t-gh-109638-a-security-problem-doesn-t-it-deserve-a-cve/108883 "2026-09-04T18:00:52Z")
When looking the pull request gh-154867 (fix for gh-98820, CVE-2026-18503), I saw just next PR gh-154868 (fix for gh-109638), which however doesn’t have CVE. Shouldn’t it? It is exactly same DoS problem as the other one,… --- ## [One time ABI breakage](https://discuss.python.org/t/one-time-abi-breakage/108514)
**Author:** [@markshannon](https://discuss.python.org/u/markshannon)\ **Replies:** 26\ **Last updated:** [September 3, 2026, 8:11am UTC](https://discuss.python.org/t/one-time-abi-breakage/108514 "2026-09-03T08:11:05Z")
Abstract I’d like to propose that we have a one time break in the stable ABI, such that extensions can be compiled into one of two builds: Support versions up to 3.15 Support version 3.12 (3.14 for 32 bit builds) and … --- ## [C API: Add \`Py\_GetBuildInType\` and \`Py\_GetBuildInTypeBorrowed\`](https://discuss.python.org/t/c-api-add-py-getbuildintype-and-py-getbuildintypeborrowed/107010)
**Author:** [@bschoenmaeckers](https://discuss.python.org/u/bschoenmaeckers)\ **Replies:** 21\ **Last updated:** [September 2, 2026, 1:08pm UTC](https://discuss.python.org/t/c-api-add-py-getbuildintype-and-py-getbuildintypeborrowed/107010 "2026-09-02T13:08:34Z")
This was originally posted at C API: Add \`Py\_GetBuildInType\` and \`Py\_GetBuildInTypeBorrowed\` · Issue #148643 · python/cpython · GitHub Currently, the C API exports all build-in types as a static data export. This limits… --- ## [Python 3.15.0 candidate 2 is here!](https://discuss.python.org/t/python-3-15-0-candidate-2-is-here/108841)
**Author:** [@hugovk](https://discuss.python.org/u/hugovk)\ **Replies:** 1\ **Last updated:** [September 1, 2026, 9:19pm UTC](https://discuss.python.org/t/python-3-15-0-candidate-2-is-here/108841 "2026-09-01T21:19:14Z")
It’s the final 3.15 release candidate! This is a candidate preview of Python 3.15 This release, 3.15.0rc2, is the final planned candidate release, containing around 144 bugfixes, build improvements and documentation … --- ## [Python install manager 26.4](https://discuss.python.org/t/python-install-manager-26-4/108846)
**Author:** [@steve.dower](https://discuss.python.org/u/steve.dower)\ **Replies:** 0\ **Last updated:** [September 1, 2026, 1:05pm UTC](https://discuss.python.org/t/python-install-manager-26-4/108846 "2026-09-01T13:05:18Z")
Along with Python 3.15.0rc2, the second beta of the next Python install manager release is also available. The changes in beta 1 are more interesting (though I forgot to post about them), but the two main changes are … --- ## [Python vulnerabilities document is ready for IS/IEC review](https://discuss.python.org/t/python-vulnerabilities-document-is-ready-for-is-iec-review/108773)
**Author:** [@stephengmichell](https://discuss.python.org/u/stephengmichell)\ **Replies:** 1\ **Last updated:** [August 27, 2026, 3:42pm UTC](https://discuss.python.org/t/python-vulnerabilities-document-is-ready-for-is-iec-review/108773 "2026-08-27T15:42:50Z")
I convene ISO/IEC/JTC 1/SC 22/WG 23 Programming Language Vulnerabilities working group. He have, and are producing a set of documents that detail programming language vulnerabilities in general and in specific languages.… --- ## [Redesigning the \`turtle\` docstring translation process](https://discuss.python.org/t/redesigning-the-turtle-docstring-translation-process/108750)
**Author:** [@Stanfromireland](https://discuss.python.org/u/Stanfromireland)\ **Replies:** 7\ **Last updated:** [August 27, 2026, 4:37am UTC](https://discuss.python.org/t/redesigning-the-turtle-docstring-translation-process/108750 "2026-08-27T04:37:39Z")
turtle supports translation of its docstrings via turtle.write\_docstringdict, however no catalogues have ever been widely distributed (from what I can tell), and the documentation still directs requests to a personal ema… --- ## [Improve OSError constructor](https://discuss.python.org/t/improve-oserror-constructor/34390)
**Author:** [@storchaka](https://discuss.python.org/u/storchaka)\ **Replies:** 11\ **Last updated:** [August 26, 2026, 8:29pm UTC](https://discuss.python.org/t/improve-oserror-constructor/34390 "2026-08-26T20:29:11Z")
The purpose of introducing multiple OSError subclasses (PEP 3151) was to allow user to write except FileNotFoundError: ... instead of except OSError as e: if e.errno != errno.ENOENT: raise ... OSE… --- ## [Add the stop\_exception parameter to iter() and aiter()](https://discuss.python.org/t/add-the-stop-exception-parameter-to-iter-and-aiter/108718)
**Author:** [@storchaka](https://discuss.python.org/u/storchaka)\ **Replies:** 6\ **Last updated:** [August 24, 2026, 1:46pm UTC](https://discuss.python.org/t/add-the-stop-exception-parameter-to-iter-and-aiter/108718 "2026-08-24T13:46:56Z")
Add the stop\_exception parameter to iter() and aiter() The two-argument iter() only covers callables which report exhaustion by returning a special value. Many callables raise an exception instead — list.pop() and deque.… --- ## [Callback for subinterpreter shutdown](https://discuss.python.org/t/callback-for-subinterpreter-shutdown/108657)
**Author:** [@wjakob](https://discuss.python.org/u/wjakob)\ **Replies:** 10\ **Last updated:** [August 21, 2026, 3:02pm UTC](https://discuss.python.org/t/callback-for-subinterpreter-shutdown/108657 "2026-08-21T15:02:26Z")
Dear Python team, I’ve been experimenting with adding subinterpreter support to the nanobind binding library and ran into the following blocker where the official API seems too limited. Binding tools will generally hav… [Previous page](https://discuss.python.org/c/core-dev/23.md) [Next page](https://discuss.python.org/c/core-dev/23.md?page=2)