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Julia has more than 18k closed issues on its github. No wonder such an active user encountered a lot of it. It's not a problem with the language, though. Yes, i

Julia has more than 18k closed issues on its github. No wonder such an active user encountered a lot of it. It's not a problem with the language, though. Yes, it allows to use offsetarrays and @inbounds together, but C can read out-of-memory locations too, so what? Edit: Julia is better than C in this regard, since the usage of @inbounds is explicit, i.e. everyone can see that the code is potentially unsafe.

rob74 4y ago
I think the point he was trying to make was that the example for @inbounds from the official documentation could cause out-of-bounds accesses, while it was clearly stated that you should only use @inbounds if you are sure that no out-of-bounds accesses are possible.
- jakobnissen 4y ago
  The issue is that there is no way to verify if OOB access is possible given an abstract type, unless you know how that type behaves, i.e. how it's indexed. And Julia provides no way of specifying the behaviour of abstract types.
  - markkitti 4y ago
    > And Julia provides no way of specifying the behaviour of abstract types. I'm not sure if "no way" is accurate. There are interfaces and one could use traits. As cited above, we could use `eachindex` or `CartesianIndices` to get a list of the valid indices. The problem is enforcing and testing these interfaces.
    - jakobnissen 4y ago
      There are no interfaces in Julia. There is simply documentation, and the hope that people will read, understand, and follow it.
Gwypaas 4y ago
> but C can read out-of-memory locations too, so what? Simply decades of exploitable security issues.
- krastanov 4y ago
  The Julia example is closer to Rust's `unsafe`. Pretty much every language let's you skip bound checks, in Julia (like other modern languages) it is elective. The author was complaining about a library that decided to skip the bound check in a clumsy way (there happens to be a "correct" way to skip the bound check). It is not really about the language.
  - Gwypaas 4y ago
    Then it makes sense. Thanks for the clarification. Was worried that skipped bounds checks was something more intricate than simply explicitly annotating a statement to say "trust me, I know what I'm doing!".
masklinn 4y ago
> but C can read out-of-memory locations too, so what? So it's widely considered a plague upon the field, suffered because of the lack of alternative?

rob74 4y ago

I think the point he was trying to make was that the example for @inbounds from the official documentation could cause out-of-bounds accesses, while it was clearly stated that you should only use @inbounds if you are sure that no out-of-bounds accesses are possible.

jakobnissen 4y ago
The issue is that there is no way to verify if OOB access is possible given an abstract type, unless you know how that type behaves, i.e. how it's indexed. And Julia provides no way of specifying the behaviour of abstract types.
- markkitti 4y ago
  > And Julia provides no way of specifying the behaviour of abstract types. I'm not sure if "no way" is accurate. There are interfaces and one could use traits. As cited above, we could use `eachindex` or `CartesianIndices` to get a list of the valid indices. The problem is enforcing and testing these interfaces.
  - jakobnissen 4y ago
    There are no interfaces in Julia. There is simply documentation, and the hope that people will read, understand, and follow it.

Gwypaas 4y ago

> but C can read out-of-memory locations too, so what? Simply decades of exploitable security issues.

krastanov 4y ago
The Julia example is closer to Rust's `unsafe`. Pretty much every language let's you skip bound checks, in Julia (like other modern languages) it is elective. The author was complaining about a library that decided to skip the bound check in a clumsy way (there happens to be a "correct" way to skip the bound check). It is not really about the language.
- Gwypaas 4y ago
  Then it makes sense. Thanks for the clarification. Was worried that skipped bounds checks was something more intricate than simply explicitly annotating a statement to say "trust me, I know what I'm doing!".

masklinn 4y ago

> but C can read out-of-memory locations too, so what? So it's widely considered a plague upon the field, suffered because of the lack of alternative?