Is this really the state of "software engineering" today? :/
mushware*
Rewrite Bun in Rust has been merged
331–340 of 822 posts
Re: Rewrite Bun in Rust has been merged
#332Earlier quoted context omitted.
The half of the files contain 'unsafe' keyword? It doesn't seem as a good rewrite. What is the point of rewrite into Rust, if ~half of your code is still unsafe?
Rust has a ton of other features besides safe. Like exhaustive checking of enum variants and the ability to avoid using null with option and result.
Zig has these modern language features too fwiw.
I think the goal was to do a massive rewrite for Anthropic (they acquired bun) and show that rewriting projects from lang -> lang with Claude can reduce security vulnerabilities to help with the hype for an IPO.
I don’t use/know Rust so I can’t comment on the quality, but there was a public security review that found issues with the new Rust code: https://x.com/SwivalAgent/status/2054468328119279923
This is an interesting experiment but I’m skeptical of any claims of success by Jarred/Anthropic due to the incentive to hype agents. There’s probably a trillion dollars at stake with the IPO. And Anthropic seems to be developing this part of their business with Mythos and the super review features.
But I’d like to see the same experiment done on a project without so much relying on the story being success.
Re: Rewrite Bun in Rust has been merged
#333> +1009257 -4024 Bun is now over 1M lines of Rust code. This is approaching the size of the Rust compiler itself; except that BunJs is mostly a JavaScript interpreter wrapper + a reimplementation of the NodeJS library (Rust STD wrapper). I think BunJS is becoming the canary for software complexity management in the LLM era.
The Bun codebase had a similar number of lines of code before the rewrite.
There's nothing unusual about a rewrite coming in with a similar LOC number.
Re: Rewrite Bun in Rust has been merged
#334I have full faith, it's the same really smart people that built bun (Jarred and team) that have spearheaded this and are running it. So I have no reason to believe that this was done carelessly. That said, I'm still shocked and amazed that something this big is possible these days. But as we've seen multiple times now, one of the most important things your codebase can have is a solid test suite. I will continue to u…
yeah but it also made some tests pass by changing the tests. i’m not super familiar so i’ll dig more on weekend but it seems sus pending more review. i’ve had ai do similar things that i caught in manual review. cheating the test is bad.
That's why they've merged it into canary so they can continue working on it.
Re: Rewrite Bun in Rust has been merged
#335Wow. This is going to be interesting to follow. There's absolutely no way any of this code was reviewed, but maybe we're in a post-human world now where you can trust the models to write and review the code. This is like Gastown but on a higher profile project. Will be fascinating to see how this project is able to add new features going forward (or even _if_ it will be able to). Does anyone know how exactly Bun is u…
It passed all the tests.
If you can't trust your test suite to catch an automatic language translation you shouldn't trust it at all. :)
Re: Rewrite Bun in Rust has been merged
#336$ rg 'unsafe [{]' src/ | wc -l 10428 $ rg 'unsafe [{]' src/ -l | wc -l 736 Language Files Lines Code Comments Blanks ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Rust 1443 929213 732281 116293 80639 Zig 1298 711112 574563 59118 77431 TypeScript 2604 654684 510464 82254 61966 JavaScript 4370 364928 293211 36108 35609 C 111 305123 205875 79077 20171 C++ 586 262475 217111 19004 26360 C Header 779 100979…
The half of the files contain 'unsafe' keyword? It doesn't seem as a good rewrite. What is the point of rewrite into Rust, if ~half of your code is still unsafe?
unsafe just means that you take responsibility for the safety of the code contained within. Calling into non-Rust libraries has to be wrapped in unsafe. Making syscalls has to be wrapped in unsafe.
Bun needs to interact with FFI code. This gets wrapped in unsafe blocks.
There are many places where a JavaScript interpreter and library would need to make unsafe calls and operations.
It doesn't literally mean the code is unsafe. It means the code contained within is not something that can be checked by the compiler, so the writer takes responsibility for it.
There are many low-level data munging and other benign operations that a human can demonstrate are safe, but need to be wrapped in safe because they do things outside of what the compiler can check.
Re: Rewrite Bun in Rust has been merged
#337Why would you replace an existing codebase like this instead of forking the repo instead and then making the changes?
Re: Rewrite Bun in Rust has been merged
#338Earlier quoted context omitted.
Maybe the people who "were overreacting" just happened to have more foresight than you and me? Perhaps they saw where this was heading, and that led to their "overreaction"?
In what way? Foresight about what? It was an experiment before, regardless of people's reaction at the time doesn't make it less of an experiment back then. I feel like I'm misunderstanding this entire conversation right now.
> It was an experiment before, regardless of people's reaction at the time doesn't make it less of an experiment back then. I feel like I'm misunderstanding this entire conversation right now.
Yes - I think I didn't explain my feelings well. But, now I understood them finally! So:
It was an experiment back then. Now, nine days and a million lines later, it suddenly isn't an experiment anymore? I understand there's a comprehensive test suite (yay!) but still... a million-line diff in nine days still sounds like an experiment to me.
Re: Rewrite Bun in Rust has been merged
#339I wonder if the whole acquisition was done so that they have guinea pigs that can’t say no…
or if I want to be cynical… so that they have a big enough project where they can force gigantic rewrites without considering the outcome from the project’s point of view, all so that they can fuel their marketing strategy.
To be honest, kind of obvious looking back.
Re: Rewrite Bun in Rust has been merged
#340> +1009257 -4024 Bun is now over 1M lines of Rust code. This is approaching the size of the Rust compiler itself; except that BunJs is mostly a JavaScript interpreter wrapper + a reimplementation of the NodeJS library (Rust STD wrapper). I think BunJS is becoming the canary for software complexity management in the LLM era.
The Bun codebase had a similar number of lines of code before the rewrite. There's nothing unusual about a rewrite coming in with a similar LOC number.
If anything, it's a little surprising that the Rust code isn't significantly larger because I tend to think of Rust as requiring somewhat more boilerplate than JS.