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  • 10 Comments
Joined 1 year ago
Cake day: July 3rd, 2023
  • qqq@lemmy.worldtoLinux@lemmy.ml•Debian Orphans Bcachefs-Tools: "Impossible To Maintain In Debian Stable"
    12·
    5 days ago

    This doesn’t seem to be a Rust problem, but a modern development trend appearing in a Rust tool shipped with Cargo. The issue appears to be the way things are versioned and (reading between the lines maybe?) vendoring and/or lockfiles. Lockfiles exist in a lot of modern languages and package managers: Go has go.sum, Rust has Cargo which has Cargo.lock, Python has pip which gives a few different ways to pin versions, JavaScript has npm and yarn with lock files. I’m sure there are tons of others. I’m actually surprised this doesn’t happen all the time with newer projects. Maybe it does actually and this instance just gains traction because people get to say “look Rust bad Debian doesn’t like it”.

    This seems like a big issue if you want your code to be packaged by Debian, and it doesn’t seem easy to resolve if you also want to use the modern packaging tools. I’m not actually sure how they resolve this? There are real benefits to pinning versions, but there are also real benefits to Debian’s model (of controlling all the dependencies themselves, to some extent Debian is a lockfile implemented on the OS level). Seems like a tough problem and seems like it’ll end up with a lot of newer tools just not being available in Debian (by that I mean just not packaged by Debian, they’ll likely all run fine on Debian).

  • qqq@lemmy.worldtoLinux@lemmy.ml•One Of The Rust Linux Kernel Maintainers Steps Down - Cites "Nontechnical Nonsense"
    31·
    6 days ago

    I agree and think that should be helpful, but I hesitate to say how much easier that actually makes writing sound unsafe code. I’d think most experienced C developers also implicitly know when they’re doing unsafe things, with or without an unsafe block in the language – although I think the explicit unsafe should likely help code reviewers and tired developers.

    It is possible to write highly unsafe code in Rust while each individual unsafe block appears sound. As a simple example: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=6a1428d9cae5b9343b464709573648b4 [1] Run that on Debug and Release builds. Notice the output is different? Don’t take that example as some sort of difficult case, you wouldn’t write this code, but the concepts in it are a bit worrisome. That code is a silly example, but each individual unsafe block appears sound when trying to reason only within the block. There is unsafe behavior happening outside of the unsafe blocks (the do_some_things function should raise eyebrows), and the function we ultimately end up in has no idea something unsafe has happened.

    Unsafe code in Rust is not easy, and to some extent it breaks abstractions (maybe pointers in general break abstractions to some extent?). noaliases in that playground code rightly assumes you can’t have a &ref and &mut ref to the same thing, that’s undefined behavior in Rust. Yet to understand the cause of that bug you have to look at all function calls on the way, just as you would have to in C, and one of the biggest issues in the code exists outside of an unsafe block.

    [1]: If you don’t want to click that link or it breaks, here is the code:

    fn uhoh() {
    let val = 9;
    let val_ptr: *const usize = &val;
    do_some_things(val_ptr);
    println!("{}", val);
}

fn do_some_things(val: *const usize) {
    let valref = unsafe { val.as_ref().unwrap() };
    let mut_ptr: *mut usize = val as *mut usize;
    do_some_other_things(mut_ptr, valref);
}

fn do_some_other_things(val: *mut usize, normalref: &usize) {
    let mutref = unsafe { val.as_mut().unwrap() };
    noaliases(normalref, mutref);
}

fn noaliases(input: &usize, output: &mut usize) {
    if *input < 10 {
        *output = 15;
    }
    if *input > 10 {
        *output = 5;
    }
}

fn main() {
    uhoh();
}
  • qqq@lemmy.worldtoLinux@lemmy.ml•One Of The Rust Linux Kernel Maintainers Steps Down - Cites "Nontechnical Nonsense"
    379·
    7 days ago

    No intention of validating that behavior, it’s uncalled for and childish, but I think there is another bit of “nontechnical nonsense” on the opposite side of this silly religious war: the RIIR crowd. Longstanding C projects (sometimes even projects written in dynamic languages…?) get people that know very little about the project, or at least have never contributed, asking for it to be rewritten or refactored in Rust, and that’s likely just as tiring as the defensive C people when you want to include Rust in the kernel.

    People need to chill out on both sides of this weird religious war. A programming language is just a tool: its merits in a given situation should be discussed logically.