Support deployment to wasm32-unknown-unknown without wasm-bindgen #4320

wasm32-unknown-unknown != wasm-bindgen support.

This is one of the main problems we have with RustPython, as the environment we are deploying to is a non-browser strict wasm32-unknown-unknown environment without wasm-bindgen support.

RustPython by default expects wasm32-unknown-unknown to support wasm-bindgen, thus in our fork of RustPython we have to make the following changes that can be seen in this pull request: https://github.com/demergent-labs/RustPython/pull/1/files

1

In vm/Cargo.toml:

We need to change this:

getrandom = { version = "0.2.6", features = ["js"] }

To this:

getrandom = { version = "0.2.6", features = ["custom"] }

The js feature assumes wasm-bindgen support.

2

In vm/Cargo.toml:

We need to change this:

chrono = { version = "0.4.19", features = ["wasmbind"] }

To this, or to a newer version without the wasmbind feature:

chrono = { version = "=0.4.19" }

3

In vm/Cargo.toml we need to comment out the following:

[target.'cfg(target_arch = "wasm32")'.dependencies]
wasm-bindgen = "0.2.80"

4

In vm/src/stdlib/time.rs we need to comment out everything from line 94-102, basically get rid of all of the wasm_bindgen stuff. We also need a way to provide our own time functionality, which comes from a crate called ic_cdk, which has an API ic_cdk::api::time that will give us system time for our environment.

5

In vm/src/vm/vm_object we need to comment out all wasm_bindgen functionality, from lines 45-55.

Assuming wasm-bindgen support requires us to maintain a fork with these many changes, it would be great to upstream the ability to turn off wasm-bindgen so that our fork can be much smaller or even disappear.

Thanks!