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CPython drops mandatory Rust dependency, will offer optional Rust API in Python 3.16
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CPython maintainers reversed course on making Rust a required build dependency, opting instead for an optional Rust API planned for Python 3.16.
This avoids the community backlash that accompanied mandatory Rust adoption in the Linux kernel, while still allowing gradual Rust integration. Engineers maintaining CPython builds on platforms without Rust toolchain support will not be blocked, and internal developers can opt into Rust for extension modules when it suits them.
Written by elseif from the cluster below · every claim links back to a sourceThe three things worth knowing
An optional Rust API is planned for Python 3.16 (due October 2027), shipping with the Rust zlib compression library as a test crate.
The original proposal to make Rust mandatory was dropped due to cyclic build dependencies, platform support gaps, and community resistance.
Significant technical challenges remain, including GCC support in Rust, cross-language memory sanitization, and augmenting Rust's Drop trait for Python object deallocation.
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