Claude Code uses Bun written in Rust now (simonwillison.net)

Article summary

The article discusses how Claude Code, a project by Anthropic, has started using a Rust port of Bun, a JavaScript runtime. The author investigates this claim by running commands to verify the version of Bun used by Claude Code. The results show that Claude Code is indeed using a version of Bun that is not yet publicly released, but is available in the GitHub repository. This version is a Rust port, which has sparked discussion about the project's governance and the choice of programming language.

Main themes

• Bun Rust port
• Claude Code update
• Programming language choice
• Project governance
• Zig vs Rust
• Software development

What commenters say

• The switch to Rust may indicate that Anthropic is taking ownership of the Bun project in a less open direction.
• The use of a pre-release version of Bun by Anthropic, not available to the public, raises concerns about transparency and governance.
• Some argue that the choice of Rust over Zig is a good decision due to Rust's better security features and memory safety guarantees.
• Others counter that Zig is a viable alternative to Rust and that the switch may alienate the existing Zig community.
• The discussion around the choice of programming language is seen as a distraction from the actual functionality and usefulness of the project.
• Some commenters express concerns about the potential for 'footguns' in Rust, despite its reputation for memory safety.
• The use of unsafe code in the Rust port of Bun is seen as a potential issue by some, while others argue that it is a necessary compromise for performance.
• The governance structure of the Bun project is unclear, leading to concerns about decision-making and community involvement.