Comment on WASM targets where getrandom should never work about getrandom HOT 5 CLOSED

I donno much about the range of wasm targets that exist, or what normally happens, but wasm was meant to be quite deterministic, and ours bans any form of real randomness or secrets. I'd assume that no_std wasm has basically nothing unless you'd some additional host interface that supplies it, but not really sure.

from getrandom.

This will get clarified w/ the 0.2 release (see #135). But the basic idea is:

• getrandom works perfectly fine on wasm32-unknown-emscripten and wasm32-wasi
• getrandom does not automatically work on wasm32-unknown-unknown
  • Enabling the getrandom/js cargo feature will make this target work
  • Enabling this feature essentially says "I assume I'm running in an enviornment w/ JavaScript". This includes:
    • wasm-bindgen or stdweb toolchains
    • Client-side (in Browser) or Node.js
• There are no other Rust wasm32 targets that I am aware of. If new ones are added, they would not automatically work, and a pull request to getrandom would be needed.

Comment either here or in the doc bug if the above seems unclear or incorrect.

from getrandom.

I believe the rust target is wasm32-unknown-unknown. If I read lib.rs correctly, wasm32-unknown-unknown without wasm32_bindgen or wasm32_stdweb compiles to dummy.rs, which always errors. This is correct behavior for "perfectly" deterministic wasm targets. I think this can be closed.

from getrandom.

Sounds good.

If I read lib.rs correctly, wasm32-unknown-unknown without wasm32_bindgen or wasm32_stdweb compiles to dummy.rs, which always errors. This is correct behavior for "perfectly" deterministic wasm targets. I think this can be closed.

This is correct for v0.1. For v0.2 we are changing things so that getrandom will not compile on unsupported targets (i.e. wasm32-unknown-unknown without JavaScript). See lib.rs on the 0.2 branch.

from getrandom.

I see, getrandom is already an optional dependency of rand_core and rand though, so this sounds good too.

from getrandom.