I'm not sure how much insight we can glean from looking at the number of commits and release cadence here. In the aftermath of such a major refactor/rewrite, I would expect it to take some time to get back up to their usual development speed.
Jared and the other developers are new to the Rust codebase, even if the structure is largely familiar. They're also likely focusing on other priorities right now such as tracking down instances of 'unsafe', rather than making user-facing changes (which might encourage a release).
Bugfixes could encourage rapid new releases, but perhaps the rewrite simply hasn't been very buggy? As far as I know, those on the canary channel haven't reported any major issues, or even really noticed the change. So perhaps there's little reason for new releases right now, as the team slowly churns through the backlog.
> P.S. Anthropic’s C compiler and Cursor’s FastRender web browser haven’t had any commits for months.
I always assumed those were just experiments in capability, and weren't meant to be ongoing projects. I would hope that nobody is using them directly today.
They also have made a release, in a sense, since they moved all Claude code users to it a month ago. (And apparently no one noticed).
I think they're taking things "gradually" as they are under a lot of scrutiny and no rush for full release.
Claude Code has a huge userbase. This is an impressive result so soon after the rewrite.
This is an impressive milestone for their rewrite. There are a lot of comments trying to downplay this as being unimpressive for some reason, but I can’t see them as anything other than sour grapes because the rewrite hasn’t crashed and burned like they were hoping.
It's just blind AI hate for no rhyme or reason. I've ported projects from one language to the next using Claude Code long before Bun even did this, it's very trivial for an LLM. In the case of Bun though, they have a test suite to run the entire codebase against, and so long as all of those tests pass, there's and drastically more likely chance that its correct.
Seems to be more level skepticism to me. Not "blind hate".
The LLM translation of serenity brower's javascript engine to rust and bun's translation to rust actually provide an interesting set of open source projects to compare and contrast. While there will obviously be some blind hate, there is difference in commentary on the two projects. In technical details, Adreas'/Jared's approaches and communication. That all shows me there is substance to the criticism that isn't just AI naysaying.
I've had several bun-related crashes in Claude code in the last week, which I don't remember ever seeing before then.
Does it print a bun.report link and can you paste it? I will investigate.
Claude Code most likely only uses a tiny fraction of Bun/Node features, so Claude Code switching to the Rust rewrite doesn't mean all that much.
Look, I understand being skeptical of the whole process; the discourse about this has been extremely tiring.
But at some point if “moving one of the biggest actively maintained and used codebases to it without anyone noticing” is dismissed as “it doesn’t mean all that much”, then we’ve lost the plot a little bit somewhere.
It's the equivalent of porting Unreal Engine 5 to another language and then using it exclusively to run a 2D Tetris clone. Let's wait for the next Bun release when more real-world code is hammering it before declaring victory.
(also, fwiw, a manual rewrite would be under the same scrunity and suffer from the same skepticism, at least when obviously rushed).
If you ported UE5 to, idfk, Malbolge and ran Tetris on it and someone would dismiss it as “not impressive”, I would think they lost the plot too!
LLMs are very impressive. Five years ago, the idea that we'd have software that you could ask - in English, mind you! - to rewrite an entire server side JS runtime and you'd get something which even kind of worked was squarely in the realm of science fiction. But the question isn't "is this impressive?", but rather "should the results of such a rewrite be relied upon?" (and specific to this thread, "is the fact that a use case which only touches a small subset of the features of said result appears to no be completely broken good evidence it should be?")
If you could successfully write Tetris in Malbolge, I would call that impressive indeed. Just writing Hello World was a major effort IIRC. The nature of the malbolge interpreter makes it more of a cryptography exercise than a coding one.
I'm gonna jump in here with some self promo - back in college I TA'd a class that, for a few weeks, taught Malbolge, and the only assignment was for students to write a program that printed their name.
After spending a lot of time thinking about the language, I came up with a relatively simple algorithm based on the language design - there are a few operators that mutate state, so basically just try combinations of those until your next memory cell contains the thing that you want, then lock those instructions in and advance.
Basically RNG yourself to victory.
The original code for that algorithm is here (python, + my own interpreter): https://github.com/wallstop/malbolge-toolkit/tree/dd942fb981...
I've since llmified it as an exercise.
BUT! The whole reason for this comment is to nerd say that printing stuff is relatively easy if you invest the time in learning the language's primitives and think of programming in it more as algorithms to operate on the op codes instead of literally writing code.
Now, to do more interesting things other than printing - I'd have to spend even more time thinking about the language, which I don't want to
Pretty funny that I off-handedly used Malbolge as a random pull from my brain for “an extremely weird and not-really-but-kinda programming language” without even really remembering any details about it; and then I got to learn about your project!
Thanks for sharing!
You just compared Rust to Malbolge :)
"I ported .NET framework to x86 bare metal. Here's hello world as proof."
"I ported .NET Framework to x86 bare metal. Here's proof using Hello World."
A human doing it is impressive. A human performing many computations a computer could do would be impressive. I don't get impressed when a computer computes a number. A language machine translating is just... doing what a language machine does? When a language machine starts doing something other than translation, I will be impressed. If computers starting singing without any human intervention, for example, would be incredible! C3PO knows many languages—he may know Rust and Zig. C3PO translating from Zig to Rust isn't surprising to me. Sounds par the course for a robot who knows languages.
>A language machine translating is just... doing what a language machine does?
Really? We had language machines for decades that couldn't do it. One that could was only built in the last 2 years max but that's something you expect from language machines? Lol Okay
If a machine made to do language things in this day and age having trillions of dollars invested in doing language, I am not shocked at all that a trillion dollar language machine translates programming languages. It really is not surprising to me. I'd be surprised if a trillion dollar language machine doesn't do as fundamental a linguistic capability as translation. It's like being shocked that a language machine spews out language? What else does a language machine do?
A calculator that can find all primes will be cool. A language machine that translates english into JavaScript is cool. A language machine that translates Zig into Rust is cool. Language machines are cool, not awe-inspiring or surprising to me.
You have absolutely no way to know this though.
Like, come on already.
Is it though? What’s your source for that data?
Claude Code client isn't one of the biggest actively maintained and used codebases. If it is one of the biggest, that's showing AI's tendency to waste its own tokens and your money.
Claude Code is 150k lines of Javascript that doesn't work particularly well. 150k isn't nearly "one of the biggest", even when filtering for actively maintained.
Why is porting a program from one language to another seen as some great achievement? We had f2c in the 1990s.
https://en.wikipedia.org/wiki/F2c
This isn't a valid comparison. f2c is a compiler and the output isn't intended to be human readable.
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This is akin to saying "we replaced the tires on the car and the average user didn't notice". If the entire car was replaced, then maybe we get a bit more excited.
However if "replacing small sections of code" is heralded as "the most amazing achievement in software development" then we've all lost the plot a little bit somewhere.
It makes sense both ways, no?
The reality is, of course, most people aren't going to notice. If the functionality and performance is 1:1 why would they? Is it impressive? A bit, but not how you're positioning it. People seem to forget LLMs are good at what they've learned from training data. And the LLM is good at compressing time. The only notable thing about these types of marketing spins is that a rewrite was accomplished in a small time frame that was hard to pull off before LLMs. The actual act of the move is less so.
Did the codebase improve? Is it more performant? I've seen nothing to really stake those claims with any objectiveness. Lastly: what was gained?
I'll bite.
Claude code interacts with many system processes, files, etc, as well as external APIs. Processes audio via built in dictation. Manages a bunch of nasty auth. Etc etc.
What are the categories of features that wouldn't be exercised by this class of software?
Yeah, but a lot of hard work is done by those libraries. Interaction with external interfaces would go through the tools API, which I imagine would all use the same type of code that they could focus on fixing quickly.
This is probably a stupid question - as I’m totally unfamiliar with how interpreters call into system APIs - but would those calls use the bun runtime or the JavaScript Core engine the bun runtime wraps?
Claude Code is a large codebase and uses tons of Node’s features either directly or indirectly through dependencies. fetch(), node:http, node:tls, node:os, node:net, node:fs, AbortSignal, node:child_process, node:tty, node:process, node:http2, etc.
A bigger factor is that Claude Code is owned by Anthropic. They can view issues in the combined CC+Bun as issues in one overall thing that they own. They can reproduce and test them and "Claude Code works" can be used as a target for agentic iteration on Bun.
To release this to the world and not have it be a catastrophe, they need to have confidence that Bun itself satisfies the promises that it has made, both explicitly and implicitly (bearing in mind Hyrum's law!) to all those projects out there using it, none of which are owned by Anthropic and many of which are not source visible to them. It's a much, much higher bar.
You didn't seriously expect Anthropic to seriously maintain bun as a general purpose plattform? It's clearly the Claude Code Runtime that you're graciously allowed to continue to use for your toy projects.
If that is true, isn't it a bit unconventional? What version are they using, some random Git SHA? Why couldn't that have been made to a release or a release candidate at least?
The CI/CD costs are an interesting take, most of the rebuttals to AI ROI are something like “more code doesn’t mean more value!” but if you are charging per CI run then it actually does! Particularly with CI and extra testing being the main way to prevent the loops the AI companies are shilling from going off the rails
Author here: I'm also not sure how much we can glean from any of that!!! I look forward to Anthropic or Bun releasing a retrospective after their next release that fully outlines the cost.
Given their history with previous other marketing stunts I do not expect any retrospective. The technology is real but I have little faith in open and honest communication from Anthropic.
truth. We'll just have to wait and see what the frequency and severity of bug reports is going forward. I have my biases, but I'm not going to make any forecasts here. I'm content to let the evidence dribble in. However, I don't rely on Bun for any critical systems. i.e. I realize it's easy for me to have a wait and see attitude with this one.
There is no incentive for them to be honest about the downsides and problems.