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Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

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Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#301

Post by andy12_ »

teiferer wrote: post #279
gpm wrote: post #247

Earlier quoted context omitted.

> and this is safe code, The code they are complaining about is not safe code, it is unsafe code that exposes a supposedly but not actually safe interface. They demonstrate this by using the interface to get undefined behavior. You can see this rather directly by how miri points to the exact line of unsafe code that results in undefined behavior (which isn't something miri can always do, but it can in this instance).

But how can an interface be considered safe if it actually isn't? I thought the Rust compiler guarantees safety of everything marked a such?

To make performant code sometimes requires implementing or using "unsafe" functions (it's not obligatory, and a lot of projects don't use them; but it was probably needed to map Bun's behavior 1 to 1). Those require upholding some invariants that cannot be checked by the compiler. The compiler basically goes "I trust you on this one, programmer. If you fuck this up, unsafe behavior can propagate to the rest of the code".

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#302

Post by CrimsonRain »

gorjusborg wrote: post #229

Here's the thing: I was first interested in Bun because it was written in Zig. I was interested in Zig because I respected Andrew Kelley's decision-making, and his taste matched my own. I got really excited about Bun for many reasons after that, but they essentially came down to a similar root: the decisions were ones that I respected and would probably have made myself if I had thought of them. I was a little concer…

[flagged]

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#303

Post by akkad33 »

soraminazuki wrote: post #263
lioeters wrote: post #188

Earlier quoted context omitted.

> only solution appears to be "even more AI" That's the idea, to transform businesses to be wholly dependent on "AI" service to develop software. What better way than to re/write entire codebases until no human being understands it. The Zig project know this, and its so-called "anti-AI" policy is actually pro-community and cultivating human understanding. It's not about the tool or technology, per se, it's about peop…

The one thing I can't stand about the AI zealots is their anti‑intellectualism. Even before coding agents became a thing, there were so many comments here along the lines of, "doing things properly has a learning cost! I don't have time for that nonsense because, unlike you, I'm busy actually making stuff." Now, too many people openly mock the practice of reading, writing, or understanding code altogether. It's sad t…

One thinking is most people writing software who are not software engineers prefer using AI because they don't think software is valuable in itself, it's only a way to solve a problem. So there are two camps, the other being people who like to solve "software problems". But this latter has been solved by AI

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#304

Post by dgellow »

whimsicalism wrote: post #45

It is really sad and unfortunate that coding has started falling under the omnicause. Low-denominator discourse is invading every space I find interesting and it is difficult to avoid.

What do you mean by omnicause?

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#305

Post by risyachka »

smasher164 wrote: post #60

What I don't understand is if they were going to translate Zig to unsafe Rust, why not just build a translation tool for it? You could do a one-to-one mapping of language constructs, hardcoding patterns in your codebase, and as one friend put it "Tbh they could've just hooked up zig translate-c to c2rust". They would get deterministic translation, would probably have not been a heavy investment to build, and the outp…

At this point bun is a free adspace for Anthropic and Claude. This is the only thing that would explain the rewrite

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#306

Post by flohofwoe »

mort96 wrote: post #281
kibibu wrote: post #278

Earlier quoted context omitted.

What attracted you to Bun over Deno?

I'm not the person you asked, but for me, it's the package identifiers. Demo puts URLs to web infrastructure in source files, like Go. In my opinion, this is a huge mistake. There should be a mapping from logical package identifier to web infrastructure, and this mapping should happen outside of the source files. I believe in this very strongly.

> Demo puts URLs to web infrastructure in source files, like Go.

This is optional, but also really, really handy for standalone scripts that don't need to come with a package-lock.json or deno.lock file (if you're not aware, Deno did a lot of changes to package management in later versions).

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#307

Post by risyachka »

soraminazuki wrote: post #263
lioeters wrote: post #188

Earlier quoted context omitted.

> only solution appears to be "even more AI" That's the idea, to transform businesses to be wholly dependent on "AI" service to develop software. What better way than to re/write entire codebases until no human being understands it. The Zig project know this, and its so-called "anti-AI" policy is actually pro-community and cultivating human understanding. It's not about the tool or technology, per se, it's about peop…

The one thing I can't stand about the AI zealots is their anti‑intellectualism. Even before coding agents became a thing, there were so many comments here along the lines of, "doing things properly has a learning cost! I don't have time for that nonsense because, unlike you, I'm busy actually making stuff." Now, too many people openly mock the practice of reading, writing, or understanding code altogether. It's sad t…

This is because AI is most appealing to average and below average developers and users because it makes them feel like they can finally do something.

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#308

Post by tialaramex »

mohsen1 wrote: post #276
nextaccountic wrote: post #275

Earlier quoted context omitted.

https://tsz.dev/sound-mode/ This is awesome. Typescript really needs more of this. I hope this gets more publicized and perhaps get adopted by Microsoft. I am not sure you should call it sound mode though. > It is not a mathematical proof of soundness, and it does not make third-party .d.ts files truthful. Here there are two completely unrelated things First, soundness is a mathematical thing (sorry). If something is…

Thank you for the feedback. I think I should rename the "Sound Mode" to something more honest. "Strict" is already taken so I should think of a better name. Making tsz compatible with tsc and making it sound is mathematically impossible. The history of this stuff ( https://hegel.js.org ) is telling. If you really make a sound JS checker, nobody will really use it unless you build an entire ecosystem as big as npm wit…

> TypeScript's decision to embrace existing npm ecosystem and layering .d.ts on top was a very practical decision that made it so successful.

This is basically the same argument made for C++ and I think it's not a very solid one. We know this worked, but that's not evidence that alternatives couldn't have succeeded. I think in a world where Queen never happened the prevailing wisdom would be that someone like Farrokh Bulsara (Freddie Mercury) can't be a rockstar because that seems ridiculous.

Actually speaking of royalty, Prince is an even more extreme case. You cannot use numeral-letter substitutions in song titles, that's something for kids and won't... oh unless you're Prince. Yeah, no, "Nothing Compares 2 U" is fine Prince, thanks.

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#309

Post by tialaramex »

repelsteeltje wrote: post #31
stavros wrote: post #7

I thought Rust treated undefined behaviour as a compiler bug? Does anyone know what's actually happening here?

I'm sure there have been attempts at defining a language that has no UB, but afaik all meaningful languages have UB in some dark corner or enumerated explicitly. For example, Java thread execution order is UB.

It's not difficult to have a Special Purpose language with no UB. There isn't any UB in WUFFS (a language for Wrangling Untrusted File Formats Safely) for example.

Those "dark corners" come into the picture when you decide you want a General Purpose language.

When your program might actually intend to respond to emails by executing the x86-64 machine code squirrelled away inside this logo PNG and running the output as SQL on your customer database, it's not possible for the language to ensure that programs which weren't intended to do that can't do that, how would they know? The translator isn't a mind reader, your intent is unreadable.

I think we should use general purpose languages much less often, the industry doesn't seem to agree, the results are obvious for everyone to see.

Rust has a subset, "safe Rust" which isn't a fully general purpose language but deliberately shares its syntax with a larger unsafe Rust you can use when it turns out that you needed it. Safe Rust doesn't have UB.

Re: Bun Rust rewrite: "codebase fails basic miri checks, allows for UB in safe rust"

#310

Post by mohsen1 »

tialaramex wrote: post #308
mohsen1 wrote: post #276

Earlier quoted context omitted.

Thank you for the feedback. I think I should rename the "Sound Mode" to something more honest. "Strict" is already taken so I should think of a better name. Making tsz compatible with tsc and making it sound is mathematically impossible. The history of this stuff ( https://hegel.js.org ) is telling. If you really make a sound JS checker, nobody will really use it unless you build an entire ecosystem as big as npm wit…

> TypeScript's decision to embrace existing npm ecosystem and layering .d.ts on top was a very practical decision that made it so successful. This is basically the same argument made for C++ and I think it's not a very solid one. We know this worked, but that's not evidence that alternatives couldn't have succeeded. I think in a world where Queen never happened the prevailing wisdom would be that someone like Farrokh…

In the Sound Mode page I mentioned that I have some ideas around this. What if we could take .d.ts and project a sound version out of it? How feasible that can be is unclear but the biggest unsoundness criminal is `any` which is relatively safe to project it into `unknown`. And method binvariance stuff are also not impossible to project something more sound out of it.

My goal with tsz is to make it practical and useful. I know how difficult it is to convince a tsc user to try something not officially from Microsoft

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