CPython eases Rust requirements as assimilation continues

The maintainers of CPython have backed off from making Rust a required dependency for the Python reference implementation, focusing on the less intrusive task of building an optional Rust API for internal Python development.

The move “sidesteps a lot of the concerns that people brought up,” Rust Programming Manager Tomáš Šedovič explained at RustConf, held in Montréal last week. Šedovič and others from Rust have been working with the CPython core developers to smooth the integration between the two environments.

CPython’s revised approach eschews a more aggressive push to use Rust in Python, an approach that roiled the Linux kernel community’s adoption of Rust last year.

The tasty dish is still rejected by the unwilling palate Last November, Python programmer Emma Smith floated the idea of incorporating Rust support into Python, initially for writing extension modules, but with the overall plan of making Rust a required dependency in CPython so it could be used throughout the CPython code base.

This would have been similar to the relationship between Rust and the C programming language, upon which CPython is largely built (hence the name).

C brings its share of security dangers when it comes to memory, which must be allocated and deallocated manually in code.

The memory-safe Rust eliminates this entire class of errors at compile time, hence its interest to the CPythonistas.

But, as fellow vulture Liam Proven noted at the time, the mandatory inclusion of Rust created a number of issues.

Not all Python implementations were built on platforms that supported Rust.

Plus, building Rust itself requires Python, creating cyclic dependencies in the build process.

And you have to factor in the usual curmudgeonly reluctance that comes with any forced upgrade.

So, in May, Smith amended the proposal to drop the mandate to make Rust a required dependency for CPython, kicking that down the road for a future proposal.

Instead, Smith pitched the idea of modifying CPython so its devs could write optional extension modules.

They could use Rust to build the functionality if they wanted, but it’d also be cool if they chose not to opt in.