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Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

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Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#281

Earlier quoted context omitted.

Also a few days before that: > I expect OSS to go the opposite direction: no human contribution allowed. Slop will be a nostalgic relic of 2025 & 2026. We should have seen this coming after they got acquired by Anthropic, but it's still disappointing. I'm not against large language models as a technology, just thoroughly disgusted how these "AI" companies rose to power, eating the software industry and the rest of so…

Software companies have been about automating human labor since the invention of computers. It's the whole damn point. Why do you think finance used to be (sometimes still is) the head of the IT dept? Because we automated accounting away. Then typists. Then secretaries. Then drafting. Etc etc.

> It's the whole damn point.

Believe it or not, for some of us it’s not “the whole damn point”.

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#282
post #75

Very impressive that they could do this so quickly because I have been on a similar project (porting TypeScript to Rust) for 5 months. But I guess I don't have access to Mythos and unlimited tokens. I'm also close to 100% pass rate. 99.6% at the time of writing. https://tsz.dev Rust is perfect for writing all of code using LLM. It's strict type system makes is less likely to make very dumb mistakes that other languag…

Same but for multi-threaded Postgres[0]. 96% pg regression tests pass after 1 month and 823K LOC. 8 Codex accounts at $200/mo is what i could use up with no Mythos I've also seen the benefits of Rust for this too. And making the bet that my pg experience will help me make good design choices around many of the things people have been having trouble with in pg for a long time[1]. Excited to see AI make it more possibl…

wow!

curious about your workflow for running all these accounts. different harnesses in parallel? manually switching in codex? 5.5pro only?

what works for you?

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#283

Earlier quoted context omitted.

> Rust is perfect for writing all of code using LLM. It's strict type system makes is less likely to make very dumb mistakes that other languages might allow. I question this. Yes, strong enforcement of invariants at compile time helps the LLM generate functional code since it gets rapid feedback and retraces as opposed to generating buggy code that fails at runtime in edge cases. On the other hand, Rust is a complex…

> On the other hand, Rust is a complex language prone to refactoring avalanches, where a small change in a component forces refactoring distant code. Are you saying this out of personal experience or just hypothesizing? I am working on a large, complex rust project with Claude Code and do not experience this at all.

This post has some good examples of this sort of problem: https://loglog.games/blog/leaving-rust-gamedev/

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#284
That's amazing, over time I got a few memory related crashes w/ bun but have deep respect for the performance work put in. Hopefully Rust's compiler will help even more.

Off: I'm wondering if now when more JS finds place on our machines and bundle size is 2nd place for most, would a revival of prepack or projects in the same vein would be worth it, especially with agents.

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#285
I'm a full time Zig developer, and I see this as an absolute win. I know Jarred has said in the past he feels Zig makes him more productive, but I also think it's fair to say Bun was programmed in a way that's quite cavalier towards buffer overruns. I think Jarred and the Oven team will have significantly better luck with Rust.

Some commenters have remarked they only heard of Zig because of Bun, therefore this is bad for Zig. Not so. In my opinion, there has always been a mismatch. I say with no ill will that a divorce is likely better for both parties. I genuinely believe Bun will be better software once fully converted to Rust.

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#286

Earlier quoted context omitted.

Also a few days before that: > I expect OSS to go the opposite direction: no human contribution allowed. Slop will be a nostalgic relic of 2025 & 2026. We should have seen this coming after they got acquired by Anthropic, but it's still disappointing. I'm not against large language models as a technology, just thoroughly disgusted how these "AI" companies rose to power, eating the software industry and the rest of so…

Software companies have been about automating human labor since the invention of computers. It's the whole damn point. Why do you think finance used to be (sometimes still is) the head of the IT dept? Because we automated accounting away. Then typists. Then secretaries. Then drafting. Etc etc.

There are software components out there that are the backbone of our industry, and they are not governed by multibillion dollar companies. Linux, postgres, HTTP, TCP/IP, qemu,…

It’s not that anthropic/google/openai/etc are unavoidable

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#287
post #103

Earlier quoted context omitted.

Much less than what it’d costs for a team of rust engineers. This is both amazing and scary; has been for a while now.

It costs several times what it would cost a small team of engineers, even assuming you gave the engineers more time to do it. I'm guessing (wildly) this was around 0.5M USD in compute time. You do get the result quicker, though.

Half a million is pretty damn cheap for a full rewrite into Rust of a million line of code codebase.

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#288

If this goes through, it feels like it will stoke rust on zig violence

Sadly, yes. I feel too much "violence" on both parts.

Honestly, Zig community seems the most bitter for whatever reason, while on the Rust side it seems to me that are simply overstating how great the language is and are pushy in trying to convince the other of their ideas.

If this goes through, we can all take SWE lessons from it, but I think the communities will suffer.

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#289

Earlier quoted context omitted.

Look what it can do in 6 days! Ignore the hundreds of thousands of hours put into the original architecture and test suite that made it possible in the first place.

This is such a bad faith argument. How long would it take a dev or a team of devs to do this with the same architecture and test suite? A hell of a lot longer than 6 days..

You missed the point.

People want to use stuff like this as somehow evidence for AI being able to write entire software systems in a few days. We saw the same shit with the "compiler" they made with a bunch of agents. Literally the only reason it's possible is because the hundreds of thousands of man hours and God knows how much money that was poured into the reference projects befoes the AI got anywhere near it.

To replicate this kind of thing with a green field project would take an absolute ton of spec work and requirements derivation, which will substantially eat into any savings from having AI generate it.

The accomplishment itself is interesting, and unlocks opportunities to do work no one would have bothered with before, but it doesn't represent what a lot of people desperately want it to.

Re: Bun's experimental Rust rewrite hits 99.8% test compatibility on Linux x64 glibc

#290
post #105

From 4 days ago: https://news.ycombinator.com/item?id=48019226 > 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 i…

cargo check reported over 16,000 compiler errors when I wrote that message. It could not print a version number or run JavaScript. I didn’t expect it to work this quickly and I also didn’t expect the performance to be as competitive. There’ll be a blog post with more details.

I think given the current mood of things, it would be prudent to not make such strong assertions on anything. Trust is in increasingly short supply these days.
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