feat(anvil): add support for injecting precompiles

[alexfertel]

Motivation

Resolves #7498

Solution

We add a new object-safe trait to anvil's public API called: PrecompileFactory.

pub trait PrecompileFactory {
    fn precompiles(&self) -> Vec<(Address, Precompile)>;
}

Alongside this trait we add a new precompile_factory field to NodeConfig which we populate in the with_precompile_factory builder function:

struct NodeConfig {
    pub precompile_factory: Option<Arc<dyn PrecompileFactory>>,
}

impl NodeConfig {
    #[must_use]
    pub fn with_precompile_factory(mut self, factory: impl PrecompileFactory + 'static) -> Self {
        self.precompile_factory = Some(Arc::new(factory));
        self
    }
}

This is used in the newly added inject_precompiles():

pub fn inject_precompiles<DB, I>(
    evm: &mut revm::Evm<'_, I, DB>,
    precompiles: Vec<(Address, Precompile)>,
) where
    DB: revm::Database,
{
  ...
}

Usage

From a consumer's standpoint, this looks like this (simplified for showcasing):

use alloy_network::TransactionBuilder;
use alloy_primitives::{address, Address};
use alloy_rpc_types::{TransactionRequest, WithOtherFields};
use anvil::{NodeConfig, PrecompileFactory};
use revm_primitives::{Bytes, Precompile, PrecompileResult};

const STYLUS_RPC_URL: &str = "https://stylus-testnet.arbitrum.io/rpc";
const ARB_WASM_ADDRESS: Address = address!("0000000000000000000000000000000000000071");
const ALICE: Address = address!("A11CEacF9aa32246d767FCCD72e02d6bCbcC375d");

fn my_precompile(bytes: &Bytes, _gas_limit: u64) -> PrecompileResult {
    if *bytes == Bytes::from_static(b"hello") {
        Ok((10, Bytes::from_static(b"world")))
    } else {
        Ok((10, Bytes::from_static(b"hello")))
    }
}

struct CustomPrecompileFactory;

impl PrecompileFactory for CustomPrecompileFactory {
    fn precompiles(&self) -> Vec<(Address, Precompile)> {
        vec![(ARB_WASM_ADDRESS, Precompile::Standard(my_precompile))]
    }
}

#[tokio::test(flavor = "multi_thread", worker_threads = 1)]
async fn spawns_anvil() {
    let config = NodeConfig::default()
        .silent()
        .with_eth_rpc_url(Some(STYLUS_RPC_URL))
        .with_extra_precompiles(CustomPrecompileFactory);
    let (api, _) = anvil::spawn(config).await;
    assert_eq!(api.chain_id(), 23011913);

    let tx = TransactionRequest::default()
        .with_from(ALICE)
        .with_to(ARB_WASM_ADDRESS.into())
        .with_input(Bytes::from_static(b"hello"));
    let result = api
        .call(WithOtherFields::new(tx), None, None)
        .await
        .unwrap();
    assert_eq!(result, Bytes::from_static(b"world"));
}

This looks quite clean IMO. This should mark the first step in adding support for Arbitrum precompiles and being able to decouple Optimism from the codebase.

---

Notes

• Did not use Evm::builder because of this comment.

[mattsse]

this is great!

Before making any changes to the evm crate, I think we can make this work for anvil but injecting precompiles to the evm directly which does not require changes in the utils crate

[mattsse]

this is great, this should work.

for some reason fmt keeps appending ; on some machines...
I'd appreciate if you could remove those from unchanged files so this doesn't cause conflicts with other prs that perhaps touch that code.

lgtm otherwise

[mattsse]

okay, I realized this needs a few more changes,

when we create the backend, we need to clone the precompilesfactory and keep this separately, so it's no longer behind the lock.

we also need to pass this to the executor, because currently the executor doesn't inject the precompiles, so the executor needs a Arc<dyn> clone as well

[mattsse]

we can put this in a function of Backend::new_evm_with_inspector_ref

[alexfertel]

when we create the backend, we need to clone the precompilesfactory and keep this separately, so it's no longer behind the lock.

we also need to pass this to the executor, because currently the executor doesn't inject the precompiles, so the executor needs a Arc clone as well

I see, that makes sense 👍

[mattsse]

lgtm,
we have some open prs that likely introduce conflicts, will resolve them and get this merged asap

[alexfertel]

Lovely! Thank you for the patience and the pointers.

[mattsse]

this is great,

once you have arb precompiles lmk, we'd love to inject them by default if the forked chain is arb for example