Bun's Rust Rewrite PR Merged

A massive PR (#30412) rewriting Bun's core code into Rust has been merged into the main branch. This work is drawing attention not merely as a language switch, but as a case study demonstrating the potential of large-scale, AI-assisted code migration.

Key Changes and Results

• Overwhelming scale: The work involved approximately 6,755 commits and 1,009,257 lines of code added, an extremely large-scale undertaking.
• Stability and efficiency: Existing memory leak issues were resolved, and the compiler now helps prevent memory bugs. Binary size decreased by 3MB–8MB, and benchmark performance was similar to or better than before.
• Structure preserved: The port was done while preserving the existing architecture and data structures as much as possible.

A Milestone Case for AI Coding

Regarding the fact that this rewrite was carried out in a very short amount of time, the community is raising the possibility of extensive use of LLMs (such as Claude) and AI coding tools. It stands as a 'canary'-like case showing how AI agents can manage and convert a vast codebase of up to 1 million lines, foreshadowing future changes in AI-based software engineering workflows.