Python cryptography, Rust, and Gentoo [LWN.net]

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 16:13 UTC (Thu) by mathstuf (subscriber, #69389)
In reply to: Python cryptography, Rust, and Gentoo by Sesse
Parent article: Python cryptography, Rust, and Gentoo

You're arguing that Rust makes global mutable state harder to do. Yes, it does. It is in service of helping to point out improper use of such things. That is, IMO, important in such a discussion of comparing the ease of making such declarations in each language.

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Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 16:30 UTC (Thu) by Sesse (subscriber, #53779) [Link] (6 responses)

No, I am arguing that Rust makes even simple things hard to do _without pulling in crates_. I am notably not making a comparison against C++.

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 16:46 UTC (Thu) by mathstuf (subscriber, #69389) [Link]

I'm arguing that what seems "simple" is not as simple as you might think it is based on how "easy" C and C++ have made it in the past.

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 19:36 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

Why do you even need a global state? That's an uncommon thing to use, so having users to write code is perfectly fine for that.

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 20:30 UTC (Thu) by marcH (subscriber, #57642) [Link] (3 responses)

If you think a global mutable state is a "simple thing" then you have a serious memory safety problem.

It took a very long wait, but in 2011 even C finally got a memory model that realizes concurrency has to be part of the language

https://en.wikipedia.org/wiki/C11_(C_standard_revision)

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 20:41 UTC (Thu) by Sesse (subscriber, #53779) [Link] (2 responses)

I think initializing a mutex should be simple thing!

I'm giving up this discussion; too many people are interested in arguing against strawmen, and too few people are interested in discussing the actual problem. It's pretty off-putting when a community's reaction to criticism is “who needs to do that anyway”.

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 20:59 UTC (Thu) by mathstuf (subscriber, #69389) [Link]

> I think initializing a mutex should be simple thing!

And it is, mechanically. Semantically, it is *not* a simple thing. These kinds of issues are what Rust is aiming to tackle as a whole.

Could once_cell or lazy_static be added to the stdlib? Sure. Why not yet? Maybe the API isn't sufficiently nailed down, soundness cases considered, etc. enough for the stdlib. Until then, crates.io is a handy place for these things to mature *while getting real world (ab)use*.

Some context for the C++ side of things. Improvements living in some random P paper on the ISO C++ standard committee mailings isn't going to get battle-hardened by anyone other than the author without the heroic work of making it available on existing language specs (e.g., Eric Neibler's Ranges library). This kind of stuff is nigh impossible with language features too. There is still errata coming in for `for (auto i : expr)` for crying out loud because this is undefined behavior:

std::vector<std::string> func();
// ...
for (auto i : func()[0]) // oops, you're iterating on a temporary that just got destructed
{}

Python cryptography, Rust, and Gentoo

Posted Feb 11, 2021 21:58 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

> I think initializing a mutex should be simple thing!
It's actually not. For example, on some systems mutexes can require a system call.