Using synedrion as a dependency of a pallet

[ameba23]

@HCastano wants to use synedrion as a dependency of a pallet - probably the registry pallet.

This means it needs to work on wasm with no-std - which it should do since it doesn't use the standard library and is tested on wasm.

Hernando tried making an empty #![no_std] crate with the following two dependencies:

synedrion = { path="<my local copy>", default-features=false }
frame-support = { version="29.0.0", default-features=false }

But on compiling gets the following error:

❯ cargo check --no-default-features --target wasm32-unknown-unknown
    Checking sp-io v31.0.0
error[E0152]: found duplicate lang item `panic_impl`
    --> /Users/hcastano/.cargo/registry/src/index.crates.io-6f17d22bba15001f/sp-io-31.0.0/src/lib.rs:1768:1
     |
1768 | / pub fn panic(info: &core::panic::PanicInfo) -> ! {
1769 | |     let message = sp_std::alloc::format!("{}", info);
1770 | |     #[cfg(feature = "improved_panic_error_reporting")]
1771 | |     {
...    |
1778 | |     }
1779 | | }
     | |_^
     |
     = note: the lang item is first defined in crate `std` (which `serde` depends on)
     = note: first definition in `std` loaded from /Users/hcastano/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/wasm32-unknown-unknown/lib/libstd-2bf3225a2841264f.rlib
     = note: second definition in the local crate (`sp_io`)

For more information about this error, try `rustc --explain E0152`.
error: could not compile `sp-io` (lib) due to 1 previous error

Doing cargo tree --edges features shows that serde's std feature is introduced by dependencies of frame-support, not synedrion - which is why i have made this issue here rather than in synedrion. But strangely, if we remove synedrion as a dependency, the crate will build, even though we can see that the std feature of serde is still present with cargo-tree.

But frame-support is used by our pallets with no issues.

And if i add synedrion as a dependency of the registry pallet, the pallet compiles, as does the entropy binary. So although this seems strange, im not sure its an issue. Or maybe i just can't see the issue.

[fjarri]

Is it still the case after entropyxyz/synedrion#137 ?

[ameba23]

Is it still the case after entropyxyz/synedrion#137 ?

yes - although that has for sure made a difference - on earlier commits there is a different compiler error.

[ameba23]

From @HCastano:

So you are able to get pallet-registry compiling with Synedrion as a dependency?
Are you compiling for the Wasm target and no default features?

Ah sorry no you are right with cargo build --target wasm32-unknown-unknown --no-default-features i see the same duplicate panic implementation error as above.

I am not sure how to figure this out because without synedrion as a dependency, the crate builds, but we can still see serde v1.0.204 with feature std is in the dependency tree.

I am confused that the entropy chain node still compiles when we have the registry pallet with synedrion as a dependency - does the chain node not build the runtime internally?