Remove chain::Id completely (#3173)

# Description
Matching on `chain::Id` is cumbersome because it lacks guarantees about
its values. For example, `chain::Id` can be constructed from a `u64` or
`U256` without error handling for unsupported chains.

So to match properly, we need to first convert `chain::Id` to
`chain::Chain`, and then also handle failure of conversion.

This proposal suggests replacing `chain::Id` entirely with
`chain::Chain`, which is already well-encapsulated. This change is
feasible because all scenarios where `chain::Chain` cannot be
constructed are handled appropriately—using an early `.expect()`
whenever a service is restarted.

# Changes
<!-- List of detailed changes (how the change is accomplished) -->

- [ ] Remove `chain::Id` and use `chain::Chain` instead
- [ ] Had to add `Hardhat` chain to make driver tests pass.

## How to test
Existing tests should verify no bugs were introduced.

<!--
## Related Issues

Fixes #
-->

crates/chain/src/lib.rs

@@ -18,12 +18,13 @@ pub enum Chain {
     Sepolia = 11155111,
     ArbitrumOne = 42161,
     Base = 8453,
+    Hardhat = 31337,
 }
 
 impl Chain {
     /// Returns the chain's chain ID
-    pub fn id(&self) -> Id {
-        Id(*self as u64)
+    pub fn id(&self) -> u64 {
+        *self as u64
     }
 
     /// Returns the canonical name of the chain on CoW Protocol.
@@ -37,6 +38,7 @@ impl Chain {
             Self::Sepolia => "Ethereum / Sepolia",
             Self::ArbitrumOne => "Arbitrum One",
             Self::Base => "Base",
+            Self::Hardhat => "Hardhat",
         }
     }
 
@@ -47,6 +49,9 @@ impl Chain {
                 10u128.pow(17).into()
             }
             Self::Gnosis => 10u128.pow(18).into(),
+            Self::Hardhat => {
+                panic!("unsupported chain for default amount to estimate native prices with")
+            }
         }
     }
 
@@ -59,6 +64,7 @@ impl Chain {
             Self::Sepolia => Duration::from_millis(12_000),
             Self::ArbitrumOne => Duration::from_millis(250),
             Self::Base => Duration::from_millis(2_000),
+            Self::Hardhat => panic!("unsupported block time for Hardhat chain"),
         }
     }
 
@@ -82,30 +88,13 @@ impl TryFrom<u64> for Chain {
             x if x == Self::Sepolia as u64 => Self::Sepolia,
             x if x == Self::ArbitrumOne as u64 => Self::ArbitrumOne,
             x if x == Self::Base as u64 => Self::Base,
+            x if x == Self::Hardhat as u64 => Self::Hardhat,
             _ => Err(ChainIdNotSupported)?,
         };
         Ok(network)
     }
 }
 
-/// Chain ID as defined by EIP-155.
-///
-/// https://eips.ethereum.org/EIPS/eip-155
-#[derive(Clone, Copy, Debug, Eq, PartialEq, From, Into)]
-pub struct Id(u64);
-
-impl From<U256> for Id {
-    fn from(value: U256) -> Self {
-        Self(value.as_u64())
-    }
-}
-
-impl std::fmt::Display for Id {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.0)
-    }
-}
-
 impl TryFrom<U256> for Chain {
     type Error = ChainIdNotSupported;
 

crates/driver/src/domain/eth/eip712.rs

@@ -7,25 +7,3 @@
 /// https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator
 #[derive(Debug, Clone, Copy)]
 pub struct DomainSeparator(pub [u8; 32]);
-
-#[derive(Debug)]
-pub struct DomainFields {
-    pub type_hash: &'static [u8],
-    pub name: &'static [u8],
-    pub version: &'static [u8],
-    pub chain_id: chain::Id,
-    pub verifying_contract: super::ContractAddress,
-}
-
-impl DomainSeparator {
-    pub fn new(fields: &DomainFields) -> Self {
-        let abi_string = ethabi::encode(&[
-            ethabi::Token::Uint(web3::signing::keccak256(fields.type_hash).into()),
-            ethabi::Token::Uint(web3::signing::keccak256(fields.name).into()),
-            ethabi::Token::Uint(web3::signing::keccak256(fields.version).into()),
-            ethabi::Token::Uint(ethereum_types::U256::from(u64::from(fields.chain_id))),
-            ethabi::Token::Address(fields.verifying_contract.into()),
-        ]);
-        Self(web3::signing::keccak256(abi_string.as_slice()))
-    }
-}

crates/driver/src/domain/eth/mod.rs

@@ -14,7 +14,7 @@ mod gas;
 
 pub use {
     allowance::Allowance,
-    eip712::{DomainFields, DomainSeparator},
+    eip712::DomainSeparator,
     gas::{EffectiveGasPrice, FeePerGas, Gas, GasPrice},
     number::nonzero::U256 as NonZeroU256,
     primitive_types::{H160, H256, U256},

crates/driver/src/infra/blockchain/contracts.rs

@@ -1,5 +1,6 @@
 use {
     crate::{boundary, domain::eth, infra::blockchain::Ethereum},
+    chain::Chain,
     ethcontract::dyns::DynWeb3,
     ethrpc::block_stream::CurrentBlockWatcher,
     thiserror::Error,
@@ -28,7 +29,7 @@ pub struct Addresses {
 impl Contracts {
     pub(super) async fn new(
         web3: &DynWeb3,
-        chain: chain::Id,
+        chain: Chain,
         addresses: Addresses,
         block_stream: CurrentBlockWatcher,
         archive_node_url: Option<&Url>,
@@ -130,12 +131,12 @@ pub struct CowAmmConfig {
 /// there is no known deployment for the contract on that network.
 pub fn deployment_address(
     contract: &ethcontract::Contract,
-    network_id: chain::Id,
+    chain: Chain,
 ) -> Option<eth::ContractAddress> {
     Some(
         contract
             .networks
-            .get(&network_id.to_string())?
+            .get(&chain.id().to_string())?
             .address
             .into(),
     )

crates/driver/src/infra/blockchain/mod.rs

@@ -1,6 +1,7 @@
 use {
     self::contracts::ContractAt,
     crate::{boundary, domain::eth},
+    chain::Chain,
     ethcontract::{dyns::DynWeb3, errors::ExecutionError},
     ethrpc::block_stream::CurrentBlockWatcher,
     std::{fmt, sync::Arc},
@@ -18,16 +19,16 @@ pub use self::{contracts::Contracts, gas::GasPriceEstimator};
 /// An Ethereum RPC connection.
 pub struct Rpc {
     web3: DynWeb3,
-    chain: chain::Id,
+    chain: Chain,
     url: Url,
 }
 
 impl Rpc {
     /// Instantiate an RPC client to an Ethereum (or Ethereum-compatible) node
     /// at the specifed URL.
-    pub async fn new(url: &url::Url) -> Result<Self, Error> {
+    pub async fn new(url: &url::Url) -> Result<Self, RpcError> {
         let web3 = boundary::buffered_web3_client(url);
-        let chain = web3.eth().chain_id().await?.into();
+        let chain = Chain::try_from(web3.eth().chain_id().await?)?;
 
         Ok(Self {
             web3,
@@ -36,8 +37,8 @@ impl Rpc {
         })
     }
 
-    /// Returns the chain id for the RPC connection.
-    pub fn chain(&self) -> chain::Id {
+    /// Returns the chain for the RPC connection.
+    pub fn chain(&self) -> Chain {
         self.chain
     }
 
@@ -47,6 +48,14 @@ impl Rpc {
     }
 }
 
+#[derive(Debug, Error)]
+pub enum RpcError {
+    #[error("web3 error: {0:?}")]
+    Web3(#[from] web3::error::Error),
+    #[error("unsupported chain")]
+    UnsupportedChain(#[from] chain::ChainIdNotSupported),
+}
+
 /// The Ethereum blockchain.
 #[derive(Clone)]
 pub struct Ethereum {
@@ -55,7 +64,7 @@ pub struct Ethereum {
 }
 
 struct Inner {
-    chain: chain::Id,
+    chain: Chain,
     contracts: Contracts,
     gas: Arc<GasPriceEstimator>,
     current_block: CurrentBlockWatcher,
@@ -102,7 +111,7 @@ impl Ethereum {
         }
     }
 
-    pub fn network(&self) -> chain::Id {
+    pub fn chain(&self) -> Chain {
         self.inner.chain
     }
 

crates/driver/src/infra/config/file/load.rs

@@ -11,6 +11,7 @@ use {
             solver::{self, BadTokenDetection, SolutionMerging},
         },
     },
+    chain::Chain,
     futures::future::join_all,
     number::conversions::big_decimal_to_big_rational,
     std::path::Path,
@@ -23,7 +24,7 @@ use {
 /// # Panics
 ///
 /// This method panics if the config is invalid or on I/O errors.
-pub async fn load(chain: chain::Id, path: &Path) -> infra::Config {
+pub async fn load(chain: Chain, path: &Path) -> infra::Config {
     let data = fs::read_to_string(path)
         .await
         .unwrap_or_else(|e| panic!("I/O error while reading {path:?}: {e:?}"));
@@ -40,9 +41,12 @@ pub async fn load(chain: chain::Id, path: &Path) -> infra::Config {
     });
 
     assert_eq!(
-        config.chain_id.map(chain::Id::from).unwrap_or(chain),
+        config
+            .chain_id
+            .map(|id| Chain::try_from(id).expect("unsupported chain ID"))
+            .unwrap_or(chain),
         chain,
-        "The configured chain ID does not match connected Ethereum node"
+        "The configured chain ID does not match the connected Ethereum node"
     );
     infra::Config {
         solvers: join_all(config.solvers.into_iter().map(|config| async move {

crates/driver/src/infra/liquidity/config.rs

@@ -1,5 +1,6 @@
 use {
     crate::{domain::eth, infra::blockchain::contracts::deployment_address},
+    chain::Chain,
     derive_more::Debug,
     hex_literal::hex,
     reqwest::Url,
@@ -49,7 +50,7 @@ pub struct UniswapV2 {
 impl UniswapV2 {
     /// Returns the liquidity configuration for Uniswap V2.
     #[allow(clippy::self_named_constructors)]
-    pub fn uniswap_v2(chain: chain::Id) -> Option<Self> {
+    pub fn uniswap_v2(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::UniswapV2Router02::raw_contract(), chain)?,
             pool_code: hex!("96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f")
@@ -59,7 +60,7 @@ impl UniswapV2 {
     }
 
     /// Returns the liquidity configuration for SushiSwap.
-    pub fn sushi_swap(chain: chain::Id) -> Option<Self> {
+    pub fn sushi_swap(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::SushiSwapRouter::raw_contract(), chain)?,
             pool_code: hex!("e18a34eb0e04b04f7a0ac29a6e80748dca96319b42c54d679cb821dca90c6303")
@@ -69,7 +70,7 @@ impl UniswapV2 {
     }
 
     /// Returns the liquidity configuration for Honeyswap.
-    pub fn honeyswap(chain: chain::Id) -> Option<Self> {
+    pub fn honeyswap(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::HoneyswapRouter::raw_contract(), chain)?,
             pool_code: hex!("3f88503e8580ab941773b59034fb4b2a63e86dbc031b3633a925533ad3ed2b93")
@@ -79,7 +80,7 @@ impl UniswapV2 {
     }
 
     /// Returns the liquidity configuration for Baoswap.
-    pub fn baoswap(chain: chain::Id) -> Option<Self> {
+    pub fn baoswap(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::BaoswapRouter::raw_contract(), chain)?,
             pool_code: hex!("0bae3ead48c325ce433426d2e8e6b07dac10835baec21e163760682ea3d3520d")
@@ -89,7 +90,7 @@ impl UniswapV2 {
     }
 
     /// Returns the liquidity configuration for PancakeSwap.
-    pub fn pancake_swap(chain: chain::Id) -> Option<Self> {
+    pub fn pancake_swap(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::PancakeRouter::raw_contract(), chain)?,
             pool_code: hex!("57224589c67f3f30a6b0d7a1b54cf3153ab84563bc609ef41dfb34f8b2974d2d")
@@ -100,7 +101,7 @@ impl UniswapV2 {
 
     /// Returns the liquidity configuration for liquidity sources only used on
     /// test networks.
-    pub fn testnet_uniswapv2(chain: chain::Id) -> Option<Self> {
+    pub fn testnet_uniswapv2(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::TestnetUniswapV2Router02::raw_contract(), chain)?,
             pool_code: hex!("0efd7612822d579e24a8851501d8c2ad854264a1050e3dfcee8afcca08f80a86")
@@ -126,7 +127,7 @@ pub struct Swapr {
 impl Swapr {
     /// Returns the liquidity configuration for Swapr.
     #[allow(clippy::self_named_constructors)]
-    pub fn swapr(chain: chain::Id) -> Option<Self> {
+    pub fn swapr(chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::SwaprRouter::raw_contract(), chain)?,
             pool_code: hex!("d306a548755b9295ee49cc729e13ca4a45e00199bbd890fa146da43a50571776")
@@ -152,7 +153,7 @@ pub struct UniswapV3 {
 impl UniswapV3 {
     /// Returns the liquidity configuration for Uniswap V3.
     #[allow(clippy::self_named_constructors)]
-    pub fn uniswap_v3(graph_url: &Url, chain: chain::Id) -> Option<Self> {
+    pub fn uniswap_v3(graph_url: &Url, chain: Chain) -> Option<Self> {
         Some(Self {
             router: deployment_address(contracts::UniswapV3SwapRouter::raw_contract(), chain)?,
             max_pools_to_initialize: 100,
@@ -196,7 +197,7 @@ pub struct BalancerV2 {
 impl BalancerV2 {
     /// Returns the liquidity configuration for Balancer V2.
     #[allow(clippy::self_named_constructors)]
-    pub fn balancer_v2(graph_url: &Url, chain: chain::Id) -> Option<Self> {
+    pub fn balancer_v2(graph_url: &Url, chain: Chain) -> Option<Self> {
         let factory_addresses =
             |contracts: &[&ethcontract::Contract]| -> Vec<eth::ContractAddress> {
                 contracts

crates/driver/src/infra/simulator/enso/mod.rs

@@ -1,5 +1,6 @@
 use {
     crate::domain::eth,
+    chain::Chain,
     ethrpc::block_stream::CurrentBlockWatcher,
     reqwest::ClientBuilder,
     std::time::Duration,
@@ -13,7 +14,7 @@ const GAS_LIMIT: u64 = 30_000_000;
 #[derive(Debug, Clone)]
 pub(super) struct Enso {
     url: reqwest::Url,
-    chain_id: chain::Id,
+    chain: Chain,
     current_block: CurrentBlockWatcher,
     network_block_interval: Option<Duration>,
 }
@@ -27,14 +28,10 @@ pub struct Config {
 }
 
 impl Enso {
-    pub(super) fn new(
-        config: Config,
-        chain_id: chain::Id,
-        current_block: CurrentBlockWatcher,
-    ) -> Self {
+    pub(super) fn new(config: Config, chain: Chain, current_block: CurrentBlockWatcher) -> Self {
         Self {
             url: reqwest::Url::parse(&format!("{}api/v1/simulate", config.url)).unwrap(),
-            chain_id,
+            chain,
             current_block,
             network_block_interval: config.network_block_interval,
         }
@@ -61,7 +58,7 @@ impl Enso {
             .unwrap()
             .post(self.url.clone())
             .json(&dto::Request {
-                chain_id: self.chain_id.into(),
+                chain_id: self.chain.id(),
                 from: tx.from.into(),
                 to: tx.to.into(),
                 data: tx.input.into(),

crates/driver/src/infra/simulator/mod.rs

@@ -57,7 +57,7 @@ impl Simulator {
         Self {
             inner: Inner::Enso(enso::Enso::new(
                 config,
-                eth.network(),
+                eth.chain(),
                 eth.current_block().clone(),
             )),
             eth,

crates/driver/src/infra/simulator/tenderly/mod.rs

@@ -75,7 +75,7 @@ impl Tenderly {
             .client
             .post(self.endpoint.clone())
             .json(&dto::Request {
-                network_id: self.eth.network().to_string(),
+                network_id: self.eth.chain().id().to_string(),
                 from: tx.from.into(),
                 to: tx.to.into(),
                 input: tx.input.clone().into(),

crates/shared/src/bad_token/token_owner_finder/blockscout.rs

@@ -26,6 +26,7 @@ impl BlockscoutTokenOwnerFinder {
             Chain::Sepolia => "https://eth-sepolia.blockscout.com/api",
             Chain::ArbitrumOne => "https://arbitrum.blockscout.com/api",
             Chain::Base => "https://base.blockscout.com/api",
+            Chain::Hardhat => anyhow::bail!("Hardhat chain not supported"),
         };
 
         Ok(Self {