05-15-2026
Rust on my Bun
I am surprised we are not talking about Bun.sh and how it was ported to Rust using LLM. This whole week has been fascinating!
Everything started with Anthropic acquiring Bun.sh.
Some within the bun community raised some concerns due to Anthropic's taste for the experimental, which is generally a good thing for innovation but it goes against "if it is not broken, do not fix it".
Suddenly, a PR to port bun from zig to rust was written. It sent people into a frenzy, to the point that the PR owner had to comment on the matter:
I work on Bun and this is my branch This whole thread is an overreaction. 302 comments about code that does not work. We haven't committed to rewriting. There's a very high chance all this code gets thrown out completely. I'm curious to see what a working version of this looks, what it feels like, how it performs and if/how hard it'd be to get it to pass Bun's test suite and be maintainable. I'd like to be able to compare a viable Rust version and a Zig version side by side.
-- Jarred (source)
Hilariously enough, the PR merged. We found that the entire port was mostly done by a model and a giant prompt, which was added to the repo.
And here we are now, with a ton of issue tickets being added to the repo, with titles like "all of rust codebase: This codebase fails even the most basic miri checks, allows for UB in safe rust"
I find these small moments of engineering history fascinating. People were split in the middle about the work, and they still are. There were a ton of things that could have been done process wise to improve the perception of the community, and hopefully we see a post-mortem.
Either way, I think we all benefit from events like these.