New memory strategy

[yunfengzh]

#1102

As we discussed, I suggest you to use Arc or GC to manage rhai memory.

[schungx]

Rhai already uses Arc (or Rc). That's why you got data race error. It came from simultaneous access to an Arc.

GC is not on the roadmap right now.

[yunfengzh]

As I know, python uses refcount as the basis of memory management which is proven to enough for memory safety. So if rhai has already used Arc, why you force rust mutate rule on it (you have already done it by refcount)? If you think mutate-access a var several times is unsafe, you maybe misunderstand rust safe rule.

let a = vec.get(0);
vec.push(1);
a = 1; // rust will block the line because vec.push maybe changes underly memory pointer, so a will dangle, so a = 1 will failed.

But you have used refcount to make there is no memory failure in rhai at all, why you apply rust mutate rule?

[schungx]

why you force rust mutate rule on it (you have already done it by refcount)?

Well, Python allows data races. Rust doesn't. To by-pass Rust's restrictions, you have to use unsafe code.

If you think mutate-access a var several times is unsafe, you maybe misunderstand rust safe rule.

Mutate-access a var several times is prohibited by Rust because it can enable data races.

It is not prohibited by Python, therefore you can do it in Python.

They are different languages. I suggest you move your scripting system to Python to avoid this issue.