The maintainers of CPython, the reference implementation of Python, have scaled back plans to make Rust a mandatory dependency for the language, opting instead to build an optional Rust API for internal development. This softer approach, outlined by Rust Programming Manager Tomáš Šedovič at RustConf in Montréal, is intended to bring the benefits of Rust's memory safety without triggering the kind of backlash that accompanied Rust's adoption within the Linux kernel community last year. The shift matters because it signals a more cautious, consensus-driven path for introducing a newer language into a decades-old, widely used codebase.

The original proposal, floated by Python programmer Emma Smith last November, would have made Rust a required dependency throughout CPython, mirroring its relationship with C, but this raised concerns over platform support and circular build dependencies. In May, Smith revised the plan to make Rust use optional for extension modules, a change Python creator Guido van Rossum endorsed as a gradual, sensible path. Work continues on a Rust API and build integration, targeted for the Python 3.16 release due in October 2027, with challenges remaining around compiler support, library builds, cross-language memory safety tooling and adapting Rust's Drop trait for Python's needs.