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How is the Bun rewrite in Rust going?

lockwood.dev

321–330 of 412 posts

Re: How is the Bun rewrite in Rust going?

#321
post #316

Earlier quoted context omitted.

> But postmortem is literally “post death” in Latin. Sure, that's true. It's not really relevant to people who don't speak Latin. > It’s synonymous with autopsy! This isn't true. I have no idea how you got here. In English an autopsy is a surgical procedure performed on a corpse for the purpose of identifying the cause of death. In particular, it's a noun. "Post-mortem" in the etymologically literal "after death" sen…

An autopsy is an exam that is performed postmortem. And that’s really how people are using postmortem as a noun for the analysis that they perform after the “death” of a company, so it is a synonym at least approximately, if you don’t see that I guess you don’t have a very good imagination.

Try and find me some sentences out there on the internet in which one of the words could be reasonably substituted for the other one.

They don't mean similar things and they aren't used similarly. A postmortem is, as you note in part, a report or a meeting for the purpose of producing or discussing such a report; an autopsy is a surgical procedure. They're as "synonymous" as the words "cigarette" and "cancer".

Re: How is the Bun rewrite in Rust going?

#322
post #312

Earlier quoted context omitted.

That's not surprising. Claude code is buggy enough, and releases break things often enough, that I wouldn't expect users to distinguish bugs introduced by switching to rust-based-bun from the normal garden variety bugs.

I’ve come to just expect that my CC instance will randomly “blank” and that I have to resize my terminal / use page up/page down to get it to show again. Supposedly they used a game engine to render their TUI but I’ve never had an FPS game do that.

They drive the TUI from the same thread that actual does stuff.. causing frequent freezes.

No GUI developer would ever put this on the same thread.

Re: How is the Bun rewrite in Rust going?

#323

I'm not sure Anthropic even cares about "releasing" the next version. The rust one has been in use in Claude Code for more than a month now, used by millions of people, and that's as far as they probably really worry about it. They bought Bun for Claude Code and I doubt the open source project matters to them otherwise.

Why wouldn't they? Bun is a major part of the web ecosystem, having it developed by them via AI, sounds like a gigantic pr win.

> Bun is a major part of the web ecosystem

It was never that large but it did have a shot at getting more popular - until this drama.

No one worth their salt is building on Bun anymore, the creators and maintainers of bun have demonstrated their complete lack of care around engineering and support. It’s just too risky.

Re: How is the Bun rewrite in Rust going?

#324
post #44

Earlier quoted context omitted.

Anyone know why? Can’t CC run on any JS runtime?

Yes, but it’s slower on non-bun runtimes. Nowadays, I believe they bundle bun with CC They chose to use a react rendering to native TUI renderer, which was a source of a lot of performance issues. AFAIK, they have written a new renderer.

> They chose to use a react rendering to native TUI renderer, which was a source of a lot of performance issues.

The source of the performance issue here is their own incompetence, actually. I have never in my entire career heard of a rendering pipeline as idiotic as the custom one they built.

Re: How is the Bun rewrite in Rust going?

#325

Earlier quoted context omitted.

> You don't view it as a problem that companies consistently compensate new hires higher than they are their experienced employees? It depends on the current employee and the incoming employee. They are not interchangeable cogs. Also not everyone consistently provides good value over their tenure -- a lot tend to work hard early and then for various reasons taper off. It's not necessarily their fault, but companies d…

> a lot tend to work hard early and then for various reasons taper off And you don’t think that has anything to do with incentives (or lack thereof)? > I've never been about comparing myself to others Doesn’t have to be about comparing oneself to others. More about the cost of living increasing because software engineering salaries are rising around you…

> And you don’t think that has anything to do with incentives (or lack thereof)?

No, that's almost never it. It's mostly life circumstances, burnout, frustration with management, etc.

> More about the cost of living increasing because software engineering salaries are rising around you…

We're already talking about very well-paid software engineers here. Appealing to a sense of sympathy over cost of living concerns of 1% earners and them trying to become 0.5% earners isn't exactly a strong argument here...

Re: How is the Bun rewrite in Rust going?

#326

Many repeat the point of “$165k is cheaper than team of multiple engineers working on the rewrite for a year”, which I think is flawed — the team of engineers would have produced idiomatic rust, and it would take probably 100k+ of tokens more to make the bun in rust idiomatic rust.

Yes, and curiously many of the tellings of this story don't account for the costs of the human software engineers (Jarred and the other bun team members) who guided all of this work.

Re: How is the Bun rewrite in Rust going?

#327
post #204

Earlier quoted context omitted.

I link to Jarred's writeup on bun.com, where you'll note he mentions that its being used on Prisma and Claude Code. I don't agree that using something in a very specific environment is the same as a wide release. I trust readers will either know the backstory or read the articles I link to. Such is life if they don't.

Why are you resistant to adding a sentence to the article that notes that Claude Code uses the rewrite? Do you think it would weaken the article? When I said it would improve the credibility I did mean it. My instinct on reading the article this morning was "this person doesn't know that Claude Code runs on Bun, which weakens their credibility in presenting the argument they are making here."

To me this seems like an odd preoccupation for an article that is very little about the Bun rewrite as a running program and very much about the process of the re-write and how it came to be in commits to the repository.

You could argue that the release tag isn't important - but at the top of this comment thread a member of the team confirms they delayed the release to finish some extra testing. So the ambiguity around if the project is complete and pointing to the lack of a release mirrors internal sentiment as well.

Re: How is the Bun rewrite in Rust going?

#328

Earlier quoted context omitted.

We would need to know at least: - How many people have updated Claude/Bun to the latest version. - How many subscribers care about reporting issues. Most of them are forced to use the tool against their will and have mentally checked out already. Why report issues if your employer values slop code anyway. Just log the hours and keep your head down. Maybe it is not expedient for the AI narrative to report issues! - Ho…

> How many people have updated Claude/Bun to the latest version By default, Claude Code updates itself all the time without asking for permission, so I'd say most users are on the latest versions.

I do not trust AI agents to run outside sandbox and use them only in dev container. I always use latest version available when I build container (once or twice a month). In my opinion it is to risky to allow auto update for SW which is released several times a week including weekends and is capable of/willing to do script kiddie pranks :-)

Re: How is the Bun rewrite in Rust going?

#329
post #283

Earlier quoted context omitted.

> I've heard stories of LLMs changing tests to get all the tests to pass instead of actually fixing code. That's very easy to prevent. Don't let them edit the tests! Run the test suite against a reserved copy.

That makes sense to me as a tactic to prevent that problem. But the article talks about how so much code was written so fast. Seems to me that to create that much code that fast you have to have AI produce both the code and the tests. So I am not sure in this project if the AI can edit the tests or not. I assume that because this is Anthropic the AI is doing as much as possible, which would include editing tests.

Bun had an enormous existing test suite written in TypeScript. Getting those tests to pass against the Rust version was the key thing that enabled the project.

You can go and check if the AI edited the tests yourself: look at the git history of those files in the public Bun repository.

Re: How is the Bun rewrite in Rust going?

#330
post #148

Bun’s Rust rewrite shipped in Claude Code over a month ago and barely anyone noticed. Claude Code is widely used. The Rust rewrite is going well overall. In the Bun v1.4 video, I promised a certain number of newly passing Node.js tests were added to force us to improve compatibility, and that number is not true yet. The release is delayed until it is true. The PRs to make it true are up but not merged yet. Most likel…

Jarred thank you for doing the impossible over and over. Bun is such a fun thing to use after years of npm. Good luck with your quests! Have fun
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