I don't select my engineering tools because they give me a bad feeling - I select them because they do the thing I want them to. If Bun starts having more bugs and feeling like worse software, I'll stop using it. But I will base that on data -- not a feeling I have. Jarred has done a lot of impressive stuff with Bun, and it seems unlikely he would ship this rewrite if it didn't meet his quality bar - I am willing to see him out here.
On the flip side it's not on the yt-dlp authors to test Bun's new development process and see if it results in more segfaults, OOMs, security vulnerabilities, etc. In fact it would arguably be negligent to experiment on your users if you thought there was a reasonable probability of increased security vulnerabilities.
I think there's a good argument that the responsible thing to say would be "we aren't going to immediately support running our software on a new bun release cut from main right now".
It seems a bit unfortunate to me that they've apparently already intending to never support future releases instead of planning on re-evaluating in the future. On the other hand the yt-dlp developers definitely don't owe anyone anything.
I think your final comment gets at it. If they said "OK, I am skeptical, so we're going to pause on updating to see how this Rust thing plays out" -- that sounds like a reasonable engineering decision. Saying "because they vibe coded we are dropping support for Bun" sounds political.
I don't think "political" is necessarily a bad thing. Engaging in politics is how you shape the world. The mere act of writing and maintaining yt-dlp is quite political considering the context of IP law and enforcement that we live in.
It happens that in this case that I'd disagree with their politics if that's why they are dropping Bun support - I think there's a great deal of value in moving to memory safe languages, little harm in accepting anthropic compute and funding to do so, and that use LLMs themselves is roughly value neutral (though many uses are very much not value neutral). That said reasonable people definitely disagree with me.
Stopping maintaining and testing support for upcoming versions is cheaper than doing that work.
Sure it’s political but it is also just a sane approach, to stay away from such disruptive change and treat it as wait-and-see instead of tagging along for the ride. There is not really any technical upside to tagging along and promising support.
They can do absolutely what they want with their project especially when its majority decision. There can't be no doubt about that.
Folks generally tolerate issues if they believe they’ll get better with time. I know I did for a while. If that confidence collapses, that’s not politics.
We've known for decades that machine-translated code is garbage, and should only be done as a last resort.
Seriously though, that's an overly-pedantic definition of a compiler. Broadly speaking, languages compile in a direction of decreasing abstraction. Crossing from one high-level abstraction to another is just asking for trouble, especially in this case where the target language makes very specific performance promises as long as certain abstractions are maintained.
Seems reasonable to preemptively drop support and let someone else either suffer the fallout, or get proven wrong and just pick up support again. It's not for a lack of people motivated by IA. Unless the motivation is more "use my IA generated content" than "actually consume IA generated content", of course.
I hate to be pedantic but for a whole host of environmental reasons, they are suboptimal, and it still incinerates money to lose a rocket during a flight test.
being reactive is fine if you can tolerate issues. otherwise, you need to be proactive -- don't wait for the train to hit you before you move off the tracks
Bun being replaced entirely with stochastically generated code is red flag (regardless of whether it was or not). But Bun was also acquired by a huge corporation, which has been classically a huge red flag. Both of these are plenty of reason for yt-dlp not to support Bun.
In either case, this seems like a niche use case. I've used yt-dlp for years and I've never used Bun with it. If Anthropic really wants their recent acquisition to be supported in yt-dlp, it can fork it and support it itself.
I'm glad some engineers realize that technology is inseparable from politics. It always has been. All evil came from engineers who beleived they were above politics. Selecting the tool which got the job done/made the number go up/paid a paycheck is how we got Facebook, Google, Palantir, crypto, AI, techno-fascism and neo-feudalism. None of it would've have happened without engineers blindly applying their knowledge to achieve "purely" technical results, while ignoring the social consequences. With the hindsight of the last 20 years, anyone who still advocates for an irresponsible adoption of technology should be considered automatically suspect
Even multiple people can not go through 1m lines of code for any kind of vulnerability in 7 days, let alone 'observe' more segfaults, OOMS, unsafe behavior, on who knows how many possible ways things can go wrong in this new condition.
Only guaranty is 99% tests passed, and the engineer who is paid by the same LLM company.
How in the world, any sane engineer would agree, this would be remotely a good idea to continue using this tool, for a chance that such a expensive change won't actually land in production?
I see lots of ground for that claim.
Once bitten twice shy, y'know. Maybe the first bite wasn't even from bun. If bun can't take this on the chin and come back stronger, maybe bun wasn't a good choice to begin with. I'm sure a future version of bun with a rebuilt reputation will have an easy time getting re-adopted by most projects that needed to play it safe during the transition.
I really appreciate the maintainers' effort towards this awesome project. However, I think it is fair to be a little bit less confident with the current state of Bun.
No healthy engineering team is going to do that. And I’d want to distance myself as far as I could from a project that behaves like that.
You are 100% right. This is a decision made on VIBES and not evidence. The proof is here:
> Bun was recently rewritten in Rust using Claude, and its development seems to have taken a turn towards being fully vibe-coded. This is alarming and disappointing for a number of reasons, and frankly it seems like a future headache that we'd prefer to avoid.
They haven't tested it, they haven't found a single problem. They just don't like AI code and they're clearly saying "the fact that the project tested every line of code and it passes all tests doesn't matter to us. The fact that it's vide coded by people who literally make coding LLMs also doesn't matter."
Pure ego, no data.
Like rewriting Bun in Rust? Bun is a politically oriented project now, distancing yourself from it makes some engineering sense.
...so you do use feelings in your calculation? To be clear, I have no problem with that and think there is some level of speculation you need to do when deciding what to rely on.
As a hypothetical, pretend that Bun added obfuscated binary blobs that get executed at build time. Well, your code still works and no effects show up at runtime. Are you going to keep using it or dump it based on the "feeling" that something isn't right?
You cannot take back a promise after you make it. So if you discover bugs later you cannot just leave.
This script is just a JavaScript helper to bring full YouTube support to some media download tool. It does not seem important to anyone that executing it using Bun is supported. They support the Deno and Node runtimes.
It is impossible to review the entire rewritten codebase. There are just too many lines of code, 1 million lines to be exact [1].
It’s all the same just different syntax. Which, by the way, is why it looks ugly to rust developers. The devs wanted the code to look familiar to them.
I do think they should have called this 2.0 though. Would not feel such a rush (1.3.14 has a few regressions, and no one really cares because there are lots of small rust fires now).
Overall, the bigger issue is that bun chases shiny objects. But never finishes. Just look at test stuff. Most of vistest, but not all. Most of jest, but not all. Most of pnpm, but not all. Now we have image stuff, so most of sharp, but not all. dev server? Most of vite, but you guessed it… not all. Long running process… mostly like node but with memory leaks (and a motivation for rust I’m sure).
When I saw them posting about the Image routines my heart sank. Another shiny object. Coincided with test bugs so I moved to vitest completely.
I think you are not understanding the new paradigm. The idea that 'humans are going to understand the codebase' is dead. Codebases will be maintained and reviewed by AI. You might think this is bad, but in many aspects of human history, we have traded understanding for convenience—that's the reason why we buy food at the supermarket instead of hunting for our meal. This has happened in every area of humanity, and it seems foolish to think that code generation would be immune.
Again, you might think this is a bad thing, but it’s simply how humanity has been functioning. 'Oh, but who is going to maintain this?' AI. 'Oh, but what if one day that's not possible?' Well, what if one day the electricity goes out due to solar flame or whatever? You get it?
To be clear, I'm not implying support for the merge. I am against this whole YOLO approach to engineering. Just curious how the switch is going since I haven't seen any news since the merge announcement.
And what are you referring to as "behavior"?
BUT.
"Ignore anything but actual problems" is a terrible stance to take generally for software and dependency selection. Incidents are fairly sparse, process is much easier to observe. So if you can find connections between process and incident possibility, that's a very reasonable heuristic. And it's easy to find examples of overaggressive LLM usage introducing problems into software.
The vast majority of new software is written using AI. The problem is not that it is written by AI, but rather than some people treat it like a black box. It is entirely possible to use AI to write code and verify that it is correct. Even Linus Torvalds is allowing AI generated code into the Linux kernel as long as it's managed properly.
(Hilarious in the way that's terribly sad, of course.)
Nobody knows.
It's a big slushy of emotions that I understand (both positive and negative) but it makes it so hard to actually tells what problem someone actually has when they just use "vibe coding" as a general LLM usage slur.
I'm using LLMs to assist my development and I'm measurably (in all the ways we engineers could possibly care about) doing better work faster.
https://x.com/karpathy/status/1886192184808149383
In the case of this specific port, the port was done so fast that it is clear humans did not verify the soundness of the translation. It is not clear whether this manual verification will ever occur.
That being said, most software projects were already doing "vibe coding" by Dijkstra's standards long before AI showed up. Going on vibes and forgetting that correctness even exists ;)
Guaranteeing the correctness of complex code is difficult, but it will increasingly become non-optional as we now have a billion hackers in a data center.
---
Edit: "Bun's unreleased Rust port has 13,365 unsafe blocks"
I'm using LLMs to assist my development and I'm measurably (in all the ways we
engineers could possibly care about) doing better work faster.
Writing code is rarely the limiting factor in our work.
Or did we forget software inherently is opinionated
if it works, it will keep working. they just don't want to support and maintain it and solve issues.
> Due to foreseeable compatibility and security issues
Hmm, Zig bun crashes plenty.
I wish yt-dlp linked to detail on why there are foreseeable compatibility issues. Both projects have test suites, in an ideal world they would allow fast rewrites. Maybe they want to limit inflaming the situation, but if they have spotted some specific issues it would be good to see.
I hope Bun.rs is 1.4 or even 2.0 and not a minor release, with some alpha/beta releases.
primeagen's view
Deno and Bun have decent Node compatibility, so couldn't Node APIs be used as the generic runtime interface?
--js-runtimes [deno|node|bun|quickjs]And yet none have offered to volunteer their time to maintain a downstream fork or otherwise rectify the perceived problem.
Strange.
2. Even if somehow you did make bug-free software with tests alone, even if the Rust port is at perfect parity with the Zig codebase today owing to the years of careful human work that went into building tests as a framework to guide the AI... the future can only be downhill from here. Nobody has a mental model of the new 1m loc codebase that's never read by humans, so Bun's future is committed to 100% vibecoding. Maybe the carefully planned tests minimized the worst case scenario, but the future tests will be written by Claude too.
If, and this is a big if, it turns out that there are no major problems and Bun is better off in a year from today than it is now... then somebody can just fire up Claude and fork yt-dlp to support Bun anyways and their decision doesn't matter. In any other scenario than human code becoming completely obsolete, they are simply saving themselves a headache by getting rid of a troublesome dependency.
I don't know any bad stories about ai-translated apps. Partially because it's a relatively new trend, but also because a big amount of usual vibe code fail modes are not applicable here.
There's something really satisfying about a go binary with minimal dependencies running in a busybox docker container.
> Removed: mathjs dependency. 14MB, 200+ functions. Twelve functions used. Added: Custom math utilities module (src/math-utils.js). Addition, subtraction, multiplication, division, a handful of trig functions. Co-authored-by: chatgpt. Changed: Bundle size reduced by 68%. Build time down from 12s to 4s. Module: 47 lines across 1 file. 0 tests. 0 dependencies.
That it took so long before they started trying to phase out their home-rolled library for the "hard cases" is somewhat unrealistic, although possible in a sufficiently-dysfunctional organisation. Some of the details about the problems of their homespun library are clearly anecdotes translated from other settings, and are unrealistic in the context of a mathematics / finance library. (They only noticed that interest calculations were wrong when a customer complained? Seriously?) The development of 6.1.0 (via 6.0.0) taking only two weeks isn't congruent with the rest of the story, although it may be realistic for AI-driven development (with which I am unaccustomed).
But otherwise, this is one of the more realistic satire pieces I've read.
I'm quite liking how good Claude Code Opus is at Rust + sqlx (raw SQL with type safety) + actix-web.