Remove wasmi as sc-executor backend

[bkchr]

wasmi should be removed as sc-executor backend. It was quite useful in the early days, but it will never be as fast as wasmtime which is currently the de-facto standard in Substrate. For the beginning it should probably be enough to just remove the crate and keep the current structure with sc-executor/sc-executor-wasmtime. In the future we may could merge these both crates as well to remove unneeded code and to simplify the entire structure.

[ghost]

As substrate is a framework, shouldn't this removal be done via a deprecation process?

[bkchr]

wasmtime is already the default since quite some time.

[liuchengxu]

I notice Interpreted is still used as the default in some places though, probably nicer to update them to use Compiled and deprecate Interpreted.

substrate/test-utils/client/src/lib.rs

Line 289 in e374a33

NativeElseWasmExecutor::new(WasmExecutionMethod::Interpreted, None, 8, 2)

substrate/client/executor/src/wasm_runtime.rs

Lines 55 to 58 in 024bfce

	impl Default for WasmExecutionMethod {
	fn default() -> WasmExecutionMethod {
	WasmExecutionMethod::Interpreted
	}

[koute]

As substrate is a framework, shouldn't this removal be done via a deprecation process?

For any practical use-case the wasmi-based executor is useless as it's too slow, and it's mostly still here for historical reasons. No one should really be using it, but people do end up still accidentally using it since it's there, and then they encounter weird issues (either because it's too slow, or because almost no one uses it so it receives very little testing).

It makes sense to just remove it.

[ghost]

useless
No one should really be using it
but people do end up still accidentally using it

core dev manual

No functionality should be removed without a deprecation warning period. In rust code: Use construct xyz...

[bkchr]

Just because we remove the backend, doesn't mean that we can not put out these warnings. Especially for users (which hopefully don't use it) we can print warnings.

[ghost]

Just because we remove the backend, doesn't mean that we can not put out these warnings.

I talk about functionality-deprecation.

You talk about functionality-slaughter.

All good, just go on.

[bkchr]

There is no functionality slaughter. The wasmtime backend is doing exactly the same, faster and better. Not sure why we should keep something around that is not maintained anymore.

[ghost]

Not sure why we should keep something around that is not maintained anymore.

Not "keep"...

As substrate is a framework, shouldn't this removal be done via a deprecation process?

=> remove via a deprecation-process (= standard practice)

[yjhmelody]

I could cleanup wasmi-executor, It's not hard for me to remove it.

[bkchr]

@yjhmelody feel free to remove it!!

[yjhmelody]

be happy to do it after #13740