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Comment by rjzzleep

3 days ago

I'd argue, that while null ref and those classes of bugs may decrease, logic errors will increase. Rust is not an extraordinary readable language in my opinion, especially in the kernel where the kernel has its own data structures. IMHO Apple did it right in their kernel stack, they have a restricted subset of C++ that you can write drivers with.

Which is also why in my opinion Zig is much more suitable, because it actually addresses the readability aspect without bring huge complexity with it.

> I'd argue, that while null ref and those classes of bugs may decrease, logic errors will increase.

To some extent that argument only makes sense; if you can find a way to greatly reduce the incidence of non-logic bugs while not addressing other bugs then of course logic bugs would make up a greater proportion of what remains.

I think it's also worth considering the fact that while Rust doesn't guarantee that it'll catch all logic bugs, it (like other languages with more "advanced" type systems) gives you tools to construct systems that can catch certain kinds of logic bugs. For example, you can write lock types in a way that guarantees at compile time that you'll take locks in the correct order, avoiding deadlocks [0]. Another example is the typestate pattern [1], which can encode state machine transitions in the type system to ensure that invalid transitions and/or operations on invalid states are caught at compile time.

These, in turn, can lead to higher-order benefits as offloading some checks to the compiler means you can devote more attention to things the compiler can't check (though to be fair this does seem to be more variable among different programmers).

> Rust is not an extraordinary readable language in my opinion, especially in the kernel where the kernel has its own data structures.

The above notwithstanding, I'd imagine it's possible to think up scenarios where Rust would make some logic bugs more visible and others less so; only time will tell which prevails in the Linux kernel, though based on what we know now I don't think there's strong support for the notion that logic bugs in Rust are a substantially more common than they have been in C, let alone because of readability issues.

Of course there's the fact that readability is very much a personal thing and is a multidimensional metric to boot (e.g., a property that makes code readable in one context may simultaneously make code less readable in another). I don't think there would be a universal answer here.

[0]: https://lwn.net/Articles/995814/

[1]: https://cliffle.com/blog/rust-typestate/

> Zig is much more suitable, because it actually addresses the readability aspect

How? It doesn't look very different from Rust. In terms of readability Swift does stand out among LLVM frontends, don't know if it is or can be used for systems programming though.

  • Apple claims Swift can be used for systems programming, and is (partly) eating its own dogfood by using it in FoundationDB (https://www.swift.org/get-started/embedded/)

    I think they are right in that claim, but in making it so, at least some of the code loses some of the readability of Swift. For truly low-level code, you’ll want to give up on classes, may not want to have copy-on-write collections, and may need to add quite a few some annotations.

    • Swift is very slow relative to rust or c though. You can also cause seg faults in swift with a few lines. I Don't find any of these languages particularly difficult to read, so I'm not sure why this is listed as a discriminator between them.

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Rust is a lot more explicit. I suspect logic bugs will be much less common. It's far easier to model complexity in Rust.

I would expect the opposite. C requires you to deal with extreme design complexity in large systems because the language offers nothing to help.