Python Language Summit 2024

Episode Deep Dive

Guests and Their Background

• Seth Michael Larson Seth is the Python Software Foundation’s (PSF) Security Developer in Residence. He works on security-related improvements for both CPython and the broader Python packaging ecosystem. Seth also maintains several open-source libraries in the HTTP and networking space (e.g., requests, urllib3, truststore).

1. Python Language Summit Overview

• The summit is an invite-only event of about 50 participants at PyCon US, focusing on Python’s evolution.
• Seth attended and blogged about the various sessions to give the community insight into the current priorities and proposals for the language.

2. Security and the XZ Utils Incident

• XZ Utils Backdoor: Seth explained how a long-game attack on the XZ compression library influenced discussions around Python’s release and contribution model.
• PSF as a CVE Numbering Authority: Python can now directly issue CVEs for security vulnerabilities in CPython and key tools, streamlining security fixes and announcements.
  • Learn more about CVEs at cve.mitre.org.

3. The New Python REPL (PyREPL)

• Python 3.13 is introducing a new REPL (interactive interpreter) implemented in Python rather than C, making it easier to maintain and extend.
• It aims to improve usability for everyone, including those just learning Python (e.g., better multiline editing and potentially color enhancements down the road).

4. Year-Based (Calendar) Versioning Proposal

• There is a proposal to align CPython’s release numbering with the year of release, such as 3.24, 3.25, etc.
• This would simplify understanding support windows, given Python’s annual release cadence. A PEP is being drafted to finalize these details.

5. Free-Threaded Python (No GIL Builds)

• Python 3.13 allows an experimental build that removes the Global Interpreter Lock (GIL).
• Users can try it by installing or building Python with special flags or via the separate “python_t” binary on some platforms.
• While performance can improve for certain parallel workloads, existing C extensions must explicitly support this “no-GIL” mode.

6. Python on Mobile (Android and iOS)

• Thanks to efforts by the BeeWare team and Anaconda, Python 3.13 includes tier-three support for iOS and Android.
• This means more active testing and contributions, with the goal of enabling Python to run reliably on mobile devices.
  • Learn more about BeeWare’s work at BeeWare Project.

7. Debugger Discussion (PDB)

• Core developers discussed whether the built-in debugger, pdb, should move outside of the standard library to simplify development and allow breaking changes that improve usability.
• Concerns included losing the prominence pdb currently enjoys by being in the standard library versus the flexibility of external releases.

8. Subinterpreters and Efficient Data Sharing

• Discussion around sharing data between subinterpreters (an alternative approach to parallelism alongside or instead of free-threading)
• Tools such as MemHive (demonstrated by Yuri Selivanov) offer immutable data structures to safely share data between subinterpreters.

Overall Takeaway

The 2024 Python Language Summit showcased a range of forward-looking improvements for CPython, from enhanced concurrency models (free threading, subinterpreters) to better security practices (CVE numbering authority) and expansion onto new platforms (mobile). While some changes—like the new REPL or year-based versioning—aim to simplify Python’s use and adoption, others—like no-GIL builds—may fundamentally alter how we write and scale Python code. All these efforts underscore a broader theme: the Python community is simultaneously innovating in many areas while staying mindful of its core stability and ease of use.-