Python 3.13 alpha 4

[thomas (Thomas Wouters)]

It’s time for Python 3.13.0 alpha 4 (now with SPDX SBOM OMG!):

Python Release Python 3.13.0a4

This is an early developer preview of Python 3.13

Major new features of the 3.13 series, compared to 3.12

Python 3.13 is still in development. This release, 3.13.0a4, is the fourth of six planned alpha releases.

Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process.

During the alpha phase, features may be added up until the start of the beta phase (2024-05-07) and, if necessary, may be modified or deleted up until the release candidate phase (2024-07-30). Please keep in mind that this is a preview release and its use is not recommended for production environments.

Many new features for Python 3.13 are still being planned and written. Work continues apace on both the work to remove the Global Interpeter Lock, and to improve Python performance. The most notable changes so far:

• In the interactive interpreter, exception tracebacks are now colorized by default.
• A preliminary, experimental JIT was added, providing the ground work for significant performance improvements.
• Docstrings now have their leading indentation stripped, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules: aifc, audioop, chunk, cgi, cgitb, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib, lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.
• C API removals and deprecations. (Some removals present in alpha 1 have been reverted in alpha 2, as the removals were deemed too disruptive at this time.)

(Hey, fellow core developer, if a feature you find important is missing from this list, let Thomas know.)

The next pre-release of Python 3.13 will be 3.13.0a5, currently scheduled for 2023-03-12.

More resources

• Online Documentation
• PEP 719, 3.13 Release Schedule
• Report bugs at https://github.com/python/cpython/issues.
• Help fund Python directly (or via GitHub Sponsors), and support the Python community.

Enjoy the new releases

Thanks to all of the many volunteers who help make Python Development and these releases possible! Please consider supporting our efforts by volunteering yourself or through organization contributions to the Python Software Foundation.

Regards from dusky Amsterdam,

Your release team,
Thomas Wouters @thomas
Ned Deily @nad
Steve Dower @steve.dower
Łukasz Langa @ambv

[steve.dower]

Just noting that alpha 4 won’t make it onto the Microsoft Store, as some of the free-threaded build changes caused the package to be broken. Tracking the fix here (but I’m away for the weekend, so it’ll be next week).

Shouldn’t really impact many people as the Store page isn’t searchable yet, though I occasionally share the direct link for unusually keen people.

For the even more unusually keen people, or those who just want to help test the build/release process, there are new Nuget packages up for free-threaded builds (which are not yet free-threaded… but hopefully soon), and a not very obvious option in the normal Windows installer. If you do try them, I’m very interested in anything that flat out fails to launch - once you can get to a normal prompt, it becomes a regular free-threaded bug, so don’t bother to tag me on it, but if you can’t get that far please file an issue and tag me.

[brettcannon]

WASI build at Release CPython 3.13.0a4 w/ WASI SDK 20 · brettcannon/cpython-wasi-build · GitHub .

[barry (Barry Warsaw)]

CI images updated.