zlacker

>>PaulHo+(OP)
Indexing into arrays and vectors is really wise to avoid.

The same day Cloudflare had its unwrap fiasco, I found a bug in my code because of a slice that in certain cases went past the end of a vector. Switched it to use iterators and will definitely be more careful with slices and array indexes in the future.

>>emschw+bK
> Cloudflare had its unwrap fiasco,

Was it a fiasco? Really? The rust unwrap call is the equivalent to C code like this:

    int result = foo(…);
    assert(result >= 0);

If that assert tripped, would you blame the assert? Of course not. Or blame C? No. If that assert tripped, it’s doing its job by telling you there’s a problem in the call to foo().

You can write buggy code in rust just like you can in any other language.

>>joseph+QW1
The point is Rust provides more safety guarantees than C. But unwrap is an escape hatch, one that can blow up in your face. If they had taken the Haskell route and not provide unwrap at all, this wouldn't have happened.

>>elbear+J02
> The point is Rust provides more safety guarantees than C. But unwrap is an escape hatch

Nope. Rust never makes any guarantees that code is panic-free. Quite the opposite. Rust crashes in more circumstances than C code does. For example, indexing past the end of an array is undefined behaviour in C. But if you try that in rust, your program will detect it and crash immediately.

More broadly, safe rust exists to prevent undefined behaviour. Most of the work goes to stopping you from making common memory related bugs, like use-after-free, misaligned reads and data races. The full list of guarantees is pretty interesting[1]. In debug mode, rust programs also crash on integer overflow and underflow. (Thanks for the correction!). But panic is well defined behaviour, so that's allowed. Surprisingly, you're also allowed to leak memory in safe rust if you want to. Why not? Leaks don't cause UB.

You can tell at a glance that unwrap doesn't violate safe rust's rules because you can call it from safe rust without an unsafe block.

[1] https://doc.rust-lang.org/reference/behavior-considered-unde...