`cargo test` build fails when `sol_interface!` generated interfaces are used in unit tests

[chris-ricketts]

The use of sol_interface! generated interfaces causes an undefined symbols linker error when built for native arch, such as when running unit tests.

As a user, I would expect the interfaces generated by sol_interface! to be testable with TestVM::mock_*call functions.

src/lib.rs

#![cfg_attr(not(any(test)), no_main)]
extern crate alloc;

use alloy_primitives::{Address, hex};
use stylus_sdk::prelude::*;

sol_interface! {
    interface IAdder  {
        function add(uint64 a, uint64 b) external view returns (uint128);
    }
}

fn add_calldata(a: u64, b: u64) -> Vec<u8> {
    [
        [110u8, 44u8, 115u8, 45u8].as_slice(), // keccak(b"add(uint64,uint64)")[..4],
        [0u8; 24].as_slice(),                  // padding
        a.to_be_bytes().as_slice(),
        [0u8; 24].as_slice(),                  // padding
        b.to_be_bytes().as_slice(),
    ]
    .concat()
}

#[storage]
#[entrypoint]
pub struct MyContract {}

#[public]
impl MyContract {
    // cannot be called in unit tests due to use of undefined symbols (e.g. _static_call) linker error
    pub fn call_adder_iface(&self, adder: IAdder, a: u64, b: u64) -> u128 {
        adder.add(self, a, b).unwrap()
    }

    // can be called in unit tests
    pub fn call_adder_low_level(&self, adder: Address, a: u64, b: u64) -> u128 {
        let return_data = self
            .vm()
            .static_call(&calls::context::Call::new(), adder, &add_calldata(a, b))
            .expect("valid contract call");

        if return_data.len() != 32 {
            panic!("unexpected return data: {}", hex::encode(return_data))
        }

        return_data[16..]
            .try_into()
            .map(u128::from_be_bytes)
            .expect("32 bytes returned")
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use stylus_sdk::{abi, testing::*};

    #[test]
    fn test_contract() {
        let vm = TestVM::default();

        let c = MyContract::from(&vm);

        vm.mock_static_call(Address::ZERO, add_calldata(10, 5), Ok(abi::encode(&15u128)));

        assert_eq!(c.call_adder_low_level(Address::ZERO, 10, 5), 15);

        // if you uncomment the line below, `cargo t` will fail to build
        // c.call_adder_iface(IAdder::new(Address::ZERO), 10, 5);
    }
}

Cargo.toml

[package]
name = "sol-interface-breaks-test-build"
version = "0.1.0"
edition = "2024"

[lib]
crate-type = ["lib", "cdylib"]

[dependencies]
alloy-primitives = "=0.8.20"
stylus-sdk = "0.9.0"

[dev-dependencies]
alloy-primitives = { version = "=0.8.20", features = [ "tiny-keccak" ] }
stylus-sdk = { version = "0.9.0", features = ["stylus-test"] }

Linker error (aarch64-darwin rustc 1.88.0):

  = note: Undefined symbols for architecture arm64:
            "_call_contract", referenced from:
                stylus_sdk::call::raw::RawCall::call::h4525d563da11d3fc in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.1.rcgu.o)
               (maybe you meant: _$LT$stylus_sdk..host..WasmVM$u20$as$u20$stylus_core..host..UnsafeCallAccess$GT$::static_call_contract::ha04b0544e53e1858, _$LT$stylus_sdk..host..WasmVM$u20$as$u20$stylus_core..host..UnsafeCallAccess$GT$::delegate_call_contract::h1235a25d88076e86 , _$LT$stylus_test..vm..TestVM$u20$as$u20$stylus_core..host..UnsafeCallAccess$GT$::static_call_contract::h7cd318da66d7c6d5 , _$LT$stylus_test..vm..TestVM$u20$as$u20$stylus_core..host..UnsafeCallAccess$GT$::delegate_call_contract::hc703e24d77cca0cd )
            "_delegate_call_contract", referenced from:
                stylus_sdk::call::raw::RawCall::call::h4525d563da11d3fc in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.1.rcgu.o)
            "_read_return_data", referenced from:
                stylus_sdk::contract::read_return_data::hbaf2efd5885a2430 in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.0.rcgu.o)
            "_return_data_size", referenced from:
                stylus_sdk::contract::return_data_len::h00909092eca5bd34 in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.0.rcgu.o)
            "_static_call_contract", referenced from:
                stylus_sdk::call::raw::RawCall::call::h4525d563da11d3fc in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.1.rcgu.o)
            "_storage_flush_cache", referenced from:
                stylus_sdk::storage::StorageCache::flush::hf25beac3b5e6f57a in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.0.rcgu.o)
                stylus_sdk::storage::StorageCache::clear::hf4900a2d38c714f4 in libstylus_sdk-f90d910a78be94f8.rlib(stylus_sdk-f90d910a78be94f8.stylus_sdk.99c5cd16912e6307-cgu.0.rcgu.o)
          ld: symbol(s) not found for architecture arm64