Claude Code uses Bun written in Rust now • Hacker News Board

Re: Claude Code uses Bun written in Rust now

#101

Post by kstenerud » Sun, Jul 19, 2026, 11:52 AM UTC

afavour wrote: post #96

kstenerud wrote: post #57

Earlier quoted context omitted.

Why is that even a thing to object to? You're talking as if you placed stock in the bizarre idea that Anthropic would close source the project and start charging for it. Stay your pitchforks.

I wouldn’t use language as strong as OPs but it is against the spirit of FOSS for a corporate owner to use a private prerelease version of their open source software. I think it’s valid to object to. If 1.4 is good enough to be used by Claude, why not us?

So you wouldn't, for example, after doing a complete ground-up rewrite, perhaps spend a few months dogfooding it to work out the worst bugs before unleashing it upon the public, thus maximizing your initial velocity by minimizing the blast radius and support requests and triage during this phase?

Re: Claude Code uses Bun written in Rust now

#102

Post by estearum » Sun, Jul 19, 2026, 11:52 AM UTC

jasode wrote: post #83

atonse wrote: post #18

Earlier quoted context omitted.

It’s made absolutely no negative difference, as we’ve seen in the real world in the last 60 days since the merge. I feel weird having to defend reality; reality being that it was merged nearly 2 months ago and tons of people have had their pitchforks out without a shred of actual evidence that this made bun worse in any measurable way. But they still insist it was a mistake. I’ve never met Jared or the bun team but I…

>Literally who cares what language a JS toolset is written in? Maybe you're being coy by asking a rhetorical question you already know the answer to but I'll answer as if you asked sincerely... There are 2 different groups interacting with software products: (1) end-users : this is where the "Who cares what language it's written in?!?" is usually applicable. E.g. The finance guys using MS Excel don't care whether it'…

I think you're missing group 3, which is the "assume bad faith and/or bad outcome from any possible change to anything, and especially changes to open source projects that can be interpreted as exogenous, e.g. from an acquirer, and especially if that acquirer is a gigantic commercial entity."

There are not nearly enough disenfranchised Bun-on-Zig contributors to make a dent in this conversation. There are lots of Group 3s in every similar convo, for any combination of technology, project, and acquirer you can name.

Re: Claude Code uses Bun written in Rust now

#103

Post by codethief » Sun, Jul 19, 2026, 11:52 AM UTC

Incidentally, Claude Code has been very buggy for me lately (much more so than before). Lots of TUI rendering issues causing, e.g., the conversation history to be garbled etc.

Re: Claude Code uses Bun written in Rust now

#104

Post by embedding-shape » Sun, Jul 19, 2026, 11:53 AM UTC

firesteelrain wrote: post #61

afavour wrote: post #28

Earlier quoted context omitted.

No? I think OP’s comment was very clear: > The most recent release of Bun on GitHub is currently v1.3.14 from May 12th, so that v1.4.0 version number in Claude supports them shipping a preview of a not-yet-released Bun version. > And so, the FOSS project "Bun" silently dies There’s no implication that it’s because of the switch to Rust.

> The objection isn’t to the language. It’s to Claude using a version of Bun that is not available to us. I was responding to your GP comment. For weeks, it was uproar over the blanket AI move to Rust and now it’s this reason. That’s why I said the goalposts are being moved.

> For weeks, it was uproar over the blanket AI move to Rust and now it’s this reason. That’s why I said the goalposts are being moved.

I'm just one person though, and have no problem with a move to language X, using tool Y, who cares?

For "goalpost are being moved" to be valid here, you have to be able to point to someone saying one thing at one point, then same person putting a different target later. You're folding a huge group of people into one person, when that's not really accurate to do.

Re: Claude Code uses Bun written in Rust now

#105

Post by embedding-shape » Sun, Jul 19, 2026, 11:53 AM UTC

foxes wrote: post #17

junon wrote: post #5

Earlier quoted context omitted.

Why does changing to Rust kill the project? I don't understand the point here.

As an open source - community driven project? Have you looked at the repo on github? Theres thousands of PRs from claude agents or whatever. Yeah really feels like a worthwhile place to contribute lol.

> As an open source - community driven project? Have you looked at the repo on github?

FOSS as in FOSS - Free and Open Source Software. Has nothing to do with if it's community driven or not, I'm strictly talking about FOSS.

Re: Claude Code uses Bun written in Rust now

#106

Post by brabel » Sun, Jul 19, 2026, 11:54 AM UTC

feverzsj wrote: post #65

It's a transpile. And not even a good one. The generated code is far from idiomatic rust. Some may consider it an abomination.

Can you show some examples of abominable Rust code they have?

Re: Claude Code uses Bun written in Rust now

#107

Post by thevinter » Sun, Jul 19, 2026, 11:54 AM UTC

embedding-shape wrote: post #99

ranguna wrote: post #94

Earlier quoted context omitted.

The PR is public, you can build and use it as well. The anthropic team just decided to use it, and you can as well.

> The PR is public I'm talking about the 1.4.0 release: > Claude supports them shipping a preview of a not-yet-released Bun version Maybe Bun/Anthropic fixed this after Simon's initial release of the blog post, but seemingly when we both looked, it wasn't public.

> Update: The Rust version has been released as Bun canary - running bun upgrade --canary will install this release.)

Re: Claude Code uses Bun written in Rust now

#108

Post by afavour » Sun, Jul 19, 2026, 11:54 AM UTC

firesteelrain wrote: post #95

afavour wrote: post #84

Earlier quoted context omitted.

That seems illogical to me. We’re only allowed to have one objection to a project and once that’s used up we can’t air another? FWIW I don’t think people have forgotten the original objection either!

You can; it feels contrived and very social justice warrior/anti Anthropic (which on HN is in of itself almost a meme now). The main reason was because of the blanket AI move which I could understand.

I think your perception of events is pretty heavily affected by personal bias here. Objecting to a hasty AI rewrite of an entire runtime and objecting to violating the spirit of FOSS is “very social justice warrior”?

What?

Re: Claude Code uses Bun written in Rust now

#109

Post by simonw » Sun, Jul 19, 2026, 11:55 AM UTC

witx wrote: post #98

What is the actual contribution and motivation of this post?

I thought it was interesting. I didn't write this with Hacker News in mind.

(I was actually half way through writing about something related, when I thought it would be interesting to see if I could prove that I had the Rust version of Bun on my laptop already.)

Re: Claude Code uses Bun written in Rust now

#110

Post by tappaseater » Sun, Jul 19, 2026, 11:55 AM UTC

Anthropic bought Bun, so they kinda, sorta had to make this work. I am sure the cost at $145,000 in Claude time will get some attention.

I am curious how this will work going forward from FOSS perspective. Will humans be allowed to modify the generated code? Only the .md prompts for the agents? Or what?