feat/question: support compilation to wasm32 with std

[dzmitry-lahoda]

Feature Summary

cargo check --package ibc  --target wasm32-unknown-unknown  --features=std

should work.

But I get now

error: the wasm*-unknown-unknown targets are not supported by default, you may need to enable the "js" feature. For more information see: https://docs.rs/getrandom/#webassembly-support
   --> /home/dz/.cargo/registry/src/index.crates.io-6f17d22bba15001f/getrandom-0.2.11/src/lib.rs:290:9
    |
290 | /         compile_error!("the wasm*-unknown-unknown targets are not supported by \
291 | |                         default, you may need to enable the \"js\" feature. \
292 | |                         For more information see: \
293 | |                         https://docs.rs/getrandom/#webassembly-support");
    | |________________________________________________________________________^

error[E0433]: failed to resolve: use of undeclared crate or module `imp`
   --> /home/dz/.cargo/registry/src/index.crates.io-6f17d22bba15001f/getrandom-0.2.11/src/lib.rs:346:9
    |
346 |         imp::getrandom_inner(dest)?;
    |         ^^^ use of undeclared crate or module `imp`

For more information about this error, try `rustc --explain E0433`.

Proposal

Fix it, or suggest what to do.

I not sure. Would it all work if I just use ibc without std when compiling std CosmWasm contract.

This is typical for Polkadot SDK when trying to compile runtime to wasm, but in no_std. Not sure so what combination gives error in std/wasm.

May be fix should have been done long ago in getrandom. Just feature them with proper no_std/std wasm support...

[dzmitry-lahoda]

Oh it comes from

ibc-rs/Cargo.toml

Line 55 in 8f2ddfe

primitive-types = { version = "0.12.2", default-features = false, features = ["serde_no_std"] }

So need to talk to Parity to remove this check or condition serde_no_std.

[Farhad-Shabani]

I was about to point out that this usually comes from two upstream crates: tendermint-rs and primitive-types. The primitive-types one is pulled in because of the ICS-20 implementation.
But if you're compiling any chunk of the ibc-rs implementation other than ICS-20, you can roll with sub-crates like ibc-core and ibc-clients or their sub-libraries. This way, you won't have to pull in getrandom unnecessarily.

[dzmitry-lahoda]

Currently wasm32 uses same crates inside as core and alloc, and reexports, so fix should work. As real no_std (Solana?) will not use std target, things should work. Comment to PR.

[dzmitry-lahoda]

tbh I have no idea why parity preventing std wasm32 paritytech/parity-common#801 . no idea what is proper fix now.

[Farhad-Shabani]

Currently blocked on: paritytech/parity-common#805

[dzmitry-lahoda]

I patched parity, they merged, but not released yet. So all deps on deps still broken. Neither got merged #1162 as workaround.

seem blocked by all parties/sides