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> You can write safe code that crashes in rust. That absolutely violates the safety guarantee whatever the reason for it. You can write Ruby code that calls in

by wycats 12y ago

> You can write safe code that crashes in rust. That absolutely violates the safety guarantee whatever the reason for it. You can write Ruby code that calls into unsafe C code and SEGVs. This is a bug in the C code you called. It should have exposed a safe interface. You can write Rust code that calls into clearly delineated unsafe code and SEGVs. This is a bug in the unsafe code you called. It should have exposed a safe interface. Anything to the contrary is a misunderstanding of the purpose and role of unsafe code in Rust, and endangers the entire ecosystem, just as it would endanger the Ruby ecosystem if it were seen as normal for C extensions to SEGV the safe Ruby process.

nwmcsween 12y ago
'Unsafe' is a bad term, effect is much better and it is most definitely a rust issue. If the language doesn't have a way of dealing with effects it won't be able to handle them. Rust is honestly a more safe c++ and in my opinion not an alternative for c.
- wycats 12y ago
  I don't know what this means. I stand by my upstream comment.
  - TheHydroImpulse 12y ago
    Algebraic effects system.
shadowmint 12y ago
I'm not arguing any of these points. I'm just saying there are these two misconceptions: - if you write safe rust code, your code can't segfault This isn't true if your code path contains any unsafe code. - Rust code can't segfault This isn't true at all. Sure, if it does segfault its a bug in the c code / unsafe code. You're absolutely correct. ...but bugs aren't deliberate. Obviously no one is going to deliberately expose a c api that has segfaults in it. The misconception is that if you're using rust you're safe from the bugs that other programmers may have made... which is not true. There's a trust chain involved; if you depend on a library you trust it's bug free and won't delete your harddisk and crash your program, but there's a difference between trusting a library is not malicious, and trusting a library is bug free. If you have to trust the library is bug free, you're really no better off than using C++ are you? ...but people keep saying that if you use rust then there are certain types of safety that are guaranteed by the language: http://doc.rust-lang.org/reference.html#behavior-considered-unsafe http://doc.rust-lang.org/reference.html#behavior-considered-..., regardless of programmer bugs. It's just not true. Once again, I'm not arguing that safety is good or bad or whatever. My assertion is very very specific: Rust code written 100% safely can crash if it has a dependency that uses unsafe code. The assertion that 100% safely written rust code with arbitrary dependencies can't crash is false.
- dbaupp 12y ago
  > The misconception is that if you're using rust you're safe from the bugs that other programmers may have made... which is not true. Of course it's not true, but the libraries you're using will (hopefully, for the most part) be written in Rust, which increases the level of trust. > There's a trust chain involved; if you depend on a library you trust it's bug free and won't delete your harddisk and crash your program, but there's a difference between trusting a library is not malicious, and trusting a library is bug free. > If you have to trust the library is bug free, you're really no better off than using C++ are you? The libraries are written in Rust, so have all the benefits of that. It is nonsense to say that "libraries can have bugs so you might as well use C++".
  - shadowmint 12y ago
    > It is nonsense to say that "libraries can have bugs so you might as well use C++". My argument is that if you assert 'rust is 100% safe' then you must assert, all your dependencies are bug free. If you can somehow magically assert 'all my code is bug free', that would be great... but if so, you wouldn't need the borrow checker at all would you? (I'm certainly not endorsing using C++ :P I'm specifically talking to the assertion that rust code can be safe, as per the definition of safety in the guide, that certain operations are impossible; certainly, and absolutely, rust code is safer and more trust worthy (imo) than c/c++ code... but you've got to be reasonable about what you're arguing. 'rust is magical and can never crash' turns up in blog posts a lot)
    - kibwen 12y ago
      > 'rust is magical and can never crash' turns up in blog > posts a lot The next time that you see someone doing this, please correct them. Misinformation does none of us any favors.
      - kbenson 12y ago
        I believe that's what started this entire thread. ...there are two things in this article which are, I'd say, 'common misconceptions' about rust.

by wycats 12y ago

nwmcsween 12y ago

'Unsafe' is a bad term, effect is much better and it is most definitely a rust issue. If the language doesn't have a way of dealing with effects it won't be able to handle them. Rust is honestly a more safe c++ and in my opinion not an alternative for c.

wycats 12y ago
I don't know what this means. I stand by my upstream comment.
- TheHydroImpulse 12y ago
  Algebraic effects system.

shadowmint 12y ago

I'm not arguing any of these points. I'm just saying there are these two misconceptions: - if you write safe rust code, your code can't segfault This isn't true if your code path contains any unsafe code. - Rust code can't segfault This isn't true at all. Sure, if it does segfault its a bug in the c code / unsafe code. You're absolutely correct. ...but bugs aren't deliberate. Obviously no one is going to deliberately expose a c api that has segfaults in it. The misconception is that if you're using rust you're safe from the bugs that other programmers may have made... which is not true. There's a trust chain involved; if you depend on a library you trust it's bug free and won't delete your harddisk and crash your program, but there's a difference between trusting a library is not malicious, and trusting a library is bug free. If you have to trust the library is bug free, you're really no better off than using C++ are you? ...but people keep saying that if you use rust then there are certain types of safety that are guaranteed by the language: http://doc.rust-lang.org/reference.html#behavior-considered-unsafe http://doc.rust-lang.org/reference.html#behavior-considered-..., regardless of programmer bugs. It's just not true. Once again, I'm not arguing that safety is good or bad or whatever. My assertion is very very specific: Rust code written 100% safely can crash if it has a dependency that uses unsafe code. The assertion that 100% safely written rust code with arbitrary dependencies can't crash is false.

dbaupp 12y ago
> The misconception is that if you're using rust you're safe from the bugs that other programmers may have made... which is not true. Of course it's not true, but the libraries you're using will (hopefully, for the most part) be written in Rust, which increases the level of trust. > There's a trust chain involved; if you depend on a library you trust it's bug free and won't delete your harddisk and crash your program, but there's a difference between trusting a library is not malicious, and trusting a library is bug free. > If you have to trust the library is bug free, you're really no better off than using C++ are you? The libraries are written in Rust, so have all the benefits of that. It is nonsense to say that "libraries can have bugs so you might as well use C++".
- shadowmint 12y ago
  > It is nonsense to say that "libraries can have bugs so you might as well use C++". My argument is that if you assert 'rust is 100% safe' then you must assert, all your dependencies are bug free. If you can somehow magically assert 'all my code is bug free', that would be great... but if so, you wouldn't need the borrow checker at all would you? (I'm certainly not endorsing using C++ :P I'm specifically talking to the assertion that rust code can be safe, as per the definition of safety in the guide, that certain operations are impossible; certainly, and absolutely, rust code is safer and more trust worthy (imo) than c/c++ code... but you've got to be reasonable about what you're arguing. 'rust is magical and can never crash' turns up in blog posts a lot)
  - kibwen 12y ago
    > 'rust is magical and can never crash' turns up in blog > posts a lot The next time that you see someone doing this, please correct them. Misinformation does none of us any favors.
    - kbenson 12y ago
      I believe that's what started this entire thread. ...there are two things in this article which are, I'd say, 'common misconceptions' about rust.