Using Rust in Free-Threaded vs Regular Python 3.13

Explore Python 3.13's revolutionary free-threaded build and learn how Rust's memory safety guarantees can help navigate the complexities of parallel execution in this 22-minute conference talk from PyCon US. Discover the fundamental differences between Python's traditional Global Interpreter Lock (GIL) approach and the new free-threaded build that enables true parallel execution for the first time. Understand the significant performance opportunities this creates alongside the inherent challenges of parallel programming, particularly the risk of data races that can cause unpredictable crashes in compiled code. Examine how Rust's language design prevents data races by construction through its ownership system and type safety guarantees, ensuring that if code compiles, it should be free from data races unless unsafe Rust is misused. See practical examples of PyO3 Rust code written for regular Python 3.13 and observe how it must be adapted for compatibility with the free-threaded build. Learn about Rust's complementary data structures and language rules that support safe concurrent programming. Gain insights into cross-language principles that can influence how you write Python and C/C++ code to be correct in a free-threaded environment. Conclude with exciting examples of new software architectures made possible by free-threaded Python and develop an appreciation for both the complexity and potential of this groundbreaking Python feature.