Every project and programmer shouldn't feel they have to justify their choice not to use Rust (or Zig), who seem to be strangely and disproportionately pushed on Hacker News and specific other social media platforms. This includes the pressure, though a bit less in recent years, to use OOP.

If they are getting good results with C and without OOP, and people like the product, then those from outside the project shouldn't really have any say on it. It's their project.

It is also worth to note that the Rust design, in its theory, and the recent bug in the Linux kernel Rust code (the message passing abstraction used by Android), makes clear that:

1. With Rust, you may lower the exposure, but the same classes of bug still remain. And of course, all the other non memory related bugs.

2. With C you may, if you wish, develop a big sensibility to race conditions, and stay alert. In general it is possible that C programmers have their "bugs antenna" a bit more developed than other folks.

3. With Rust, to decrease the "unsafe" sections amount, you need often to build abstractions that may be a bit unnatural.

4. Rust may create a false sense of security, and in the unsafe sections the programmer sometimes, when reviewing the code, is falsely convinced by the mandatory SAFETY comment. Like in the Linux Kernel bug, where such comment was hallucinated by a human that sometimes (not sure in this specific case, it's just an example) may be less used to do the "race spotting" process that C learns you to do.

5. With Rust, in case of a bug, the fix could no longer be the one-liner usually you see in C fixes, and can make the exposure time window larger. Sometimes fixing things in Rust means refactoring in non trivial ways.

6. With C, if there was the same amount of effort in creating wrappers to make kernel programming safer at the cost of other things, the surface of attack could also be lowered in a significant way (see for instance Redis use of sds.c: how many direct strings / pointers manipulation we avoid? The same for other stuff of course). Basically things like sds.c let you put a big part of the unsafe business in a self contained library.

So, is Rust an interesting language for certain features it has? Yes. Is Rust a silver bullet? No. So should Rust be "pushed" to others, hell no, and I suggest you to reply in the most firm way to people stressing you out to adopt Rust at all the costs.

The recent bug in the Linux kernel Rust code, based on my understanding, was in unsafe code, and related to interop with C. So I wouldn't really classify it as a Rust bug. In fact, under normal circumstances (no interop), people rarely use unsafe in Rust, and the use is very isolated.

I think the idea of developers developing a "bugs antenna" is good in theory, though in practice the kernel, Redis, and many other projects suffer from these classes of bugs consistently. Additionally, that's why people use linters and code formatters even though developers can develop a sensitivity to coding conventions (in fact, these tools used to be unpopular in C-land). Trusting humans develop sensibility is just not enough.

Specifically, about the concurrency: Redis is (mostly) single-threaded, and I guess that's at least in part because of the difficulty of building safe, fast and highly-concurrent C applications (please correct me if I'm wrong).

Can people write safer C (e.g. by using sds.c and the likes)? For sure! Though we've been writing C for 50+ years at this point, at some point "people can just do X" is no longer a valid argument. As while we could, in fact we don't.