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It's not as grim as the author makes it sound... I regularly read bevy code. Sure there's some custom reflection and type erasure, but that's mostly to support

It's not as grim as the author makes it sound... I regularly read bevy code. Sure there's some custom reflection and type erasure, but that's mostly to support the highly ergonomic APIs and for optimising ECS layout and access. There are conversations (maybe even an RFC) around better supporting reflection in the language itself, which would improve the situation a lot. (Edit: some of it linked at the end of the post) Bevy is quite literally pushing Rust festures and the type system to their limits on multiple fronts, sometimes "exceeding" those limits with custom code. All with the intent of not sacrificing performance or happy path ergonomics. Of course there's going to be some unsafe.

Animats 2y ago
> maybe even an RFC I really should try to pull together my proposal for back references. A big problem in Rust is that if A owns B, B can't have a static reference to A. If you want to do that, you have to make all links to A be Rc references, and have B contain a Rc::Weak reference to A. Then there's a run-time check if you try to make the weak reference into a strong reference temporarily. Usually, the program is set to panic if that fails. The question is whether a static analysis can determine that such a weak to strong raise will never fail. If that could be proven at compile time, the reference counting would be unnecessary. And Rust could have sound back-references. If all the places where a weak link is raised to a strong link are bounded by scopes, this is probably do-able. But hard.