I don't really get the Bun thing. Bun is running Claude Code which is probably the single most actively used development app there is. You say this was a bad use of LLMs, but it's been in production for a while and I haven't heard of any evidence that Claude Code has increased a significantly larger quantity of errors, segfaults, etc, than before.

▲ Eufrat 6 hours ago | parent | next [-]

Some people, myself included, think that announcing a conversion from Rust to Zig as an experiment then jumping to putting it in the alpha train for public testing/consumption without any real explanation in the span of around 2 weeks is irresponsible and reckless.

Blogposts were promised, details were hinted, but no, it’s just full steam ahead because the AI worked so well. The converted unit tests all worked, all the synthetic tests are okay, so what are you complaining about?

At some point, it’s less about the technical questions and more about getting that pesky human buy-in.

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nine_k 2 hours ago | parent | next [-]

They are looking for a different human buy-in.

"Yes, the AI rewrote the code. No, we do not pretend that we've scrutinized the code, or that we understand it. It works, tests pass, so we don't care, and so shouldn't you."

The "recklessness" is offered as the new normal. Because it kinda, well, works for them.

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johncolanduoni 5 hours ago | parent | prev | next [-]

What does Bun’s governance look like? Now that Anthropic bought the company are there significant external contributors that would expected to have input on a decision like this?

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peteyycz 5 hours ago | parent [-]

And why buy it when they could have just called it Run and do the Rust conversion anyways? The license prohibits it, they don’t need the team’s expertise anymore, since they’re running full AI vibecode mode. Makes no sense to me

	▲	gpm 4 hours ago \| parent [-]
		Seems pretty clear that they do need the team, to direct the LLM effectively. Also they're probably interested in the team just as an acqui-hire of good developers, and they're probably interested in the marketing value of converting the actual bun to rust via LLMs. But mostly I'd assume it was about needing the team to effectively direct the LLMs.

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sharts 4 hours ago | parent | prev | next [-]

IMO it’s reckless to not pin down ones dependencies. No need to pull the latest experimental hotness

	▲	Eufrat 4 hours ago \| parent [-]
		I get that and I can see an argument that they didn’t really put it as stable, but I suspect the reason it is not the stable version right now is from the massive pushback as other projects and companies started pulling support for Bun because of the loss of confidence rather than any other reason.

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burnte 3 hours ago | parent | prev [-]

How about testing the output? Seems like the ultimate test. If the output's still good, I guess the rewrite didn't hurt.

▲ qsort 6 hours ago | parent | prev | next [-]

I agree that the Bun rewrite is much more reasonable than knee-jerk reactions imply, however:

- I don't think Claude Code is using the Rust version yet in their official build

- Claude Code is not a particularly complicated piece of software from an engineering perspective (nor it's particularly well-engineered, at least at the moment).

So in my book "it runs Claude Code" would be pretty weak evidence that the rewrite is going to be successful (the tests they've done are much better evidence, but that's a topic for another time).

▲ Wowfunhappy 5 hours ago | parent | next [-]

> - I don't think Claude Code is using the Rust version yet in their official build

No, I'm pretty sure it is, actually, since June 17:

https://code.claude.com/docs/en/changelog#2-1-181

>> Upgraded the bundled Bun runtime to 1.4

Now, Bun 1.4 doesn't seem to officially exist on https://bun.com/blog or https://github.com/oven-sh/bun/releases, so I can't be 100% sure this is the Rust version. However, I have to do some patching of the Claude Code binary to get it to run on my OS, and version 2.1.181 coincided with some changes that make suspect it's using Rust now.

	▲	andai 3 hours ago \| parent [-]
		https://news.ycombinator.com/item?id=48609168 https://grigio.org/bun-1-4-the-controversial-ai-driven-rewri... > 13,044 unsafe blocks in the resulting Rust code (hand-written Rust projects of similar size average ~73) Grok is this true? I've heard the meme that AI written rust code is absurdly full and safe blocks but... that's pretty funny. Hang on. A claim like that can be verified with a single grep! Give me a minute... `$ rg -U "unsafe\s+\{" . \| wc -l 10551` Hey, that's progress!

▲ meowface 5 hours ago | parent | prev [-]

I agree Claude Code is seemingly (currently) not very well-engineered but I think you may be moderately underestimating how complicated it is/necessarily has to be.

▲ gpm 6 hours ago | parent | prev | next [-]

> it's been in production for a while

Huh... it looks to me like bun has yet to cut a release post Zig->Rust port (the latest one on github is still on a branch that says it's written in zig in the readme). I assume that nothing is using the rust version yet...

Which also cuts against the complaints about "of course it works [...] you can put this into your production environment soon!" since they don't seem to be asserting either of those things.

	▲	Eufrat 6 hours ago \| parent [-]
		The real problem is they explained nothing and just caused a lot of mistrust. The lead developer at Bun working on this project does post here from time to time and I have never seen him answer any of this. I admire his enthusiasm, but this was badly handled mostly from Bun’s side which lead to a bunch of dogpiling. When someone on another social media platform commented expressed some concern, his response was to ask him what the explicit bug he was talking about was and that he would generate a fix. That sound you hear is the woosh as the point flies by. And in general, this just feels like a consistent problem with Bun.

▲ burnte 3 hours ago | parent | prev | next [-]

I have yet to hear any evidence that the Rust rewrite was harmful. I have no emotional investment in Bun (which I'd never heard of before the rewrite), or Zig (which I also didn't know about), or Rust (which I think is neat and that's about it), so I'm about as unbiased as you can get and from what I saw the conversion was done well, and I haven't heard of massive bugs resulting from the rewrite.

	▲	GuB-42 26 minutes ago \| parent [-]
		It is probably fine, it is kind of a best case scenario: porting a good code base with lots of unit tests, all hand-written. Not much can go wrong here as the LLM is kept in check by the original code, the tests, and the fact that the topic (a JS engine) is well documented. The problem is what comes next. They now have code that they don't understand, and they are likely to work on it with AI in the future, but the new features they may introduce later will not have the luxury of hand-written tests and a reference code. So, unless they undertake the massive effort needed to fully understand the Rust code and deal with all these "unsafe", quality is very likely to go down, Microslop style.

▲ nozzlegear 2 hours ago | parent | prev | next [-]

> which is probably the single most actively used development app there is

Seems doubtful, I'd put money on it being something like Visual Studio or Visual Studio Code. Maybe CC could claim the (odious) title of most actively used vibe-coded development app, though.

▲ MuffinFlavored 6 hours ago | parent | prev | next [-]

> Yes, Claude Code uses Bun. In fact, Claude Code relies on it as a core dependency and ships as a self-contained Bun executable.

I... somehow did not know that.

	▲	stymaar 6 hours ago \| parent [-]
		You missed the day when they had their bun build misconfigured which ended up leaking the entirety of Claude Code's codebase? (I wish I was joking)

▲ andai 3 hours ago | parent | prev [-]

Wait is the new CC running on the vibe coded Bun?