Implement delegation contract handling in EIP-7702 executor and bundler client

core/src/rpc_clients/bundler.rs

@@ -88,6 +88,12 @@ pub enum TwGetTransactionHashStatus {
     Success,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TwGetDelegationContractResponse {
+    pub delegation_contract: Address,
+}
+
 impl BundlerClient {
     /// Create a new bundler client with the given transport
     pub fn new(transport: impl IntoBoxTransport) -> Self {
@@ -170,4 +176,9 @@ impl BundlerClient {
 
         Ok(response)
     }
+
+    pub async fn tw_get_delegation_contract(&self) -> TransportResult<TwGetDelegationContractResponse> {
+        let response: TwGetDelegationContractResponse = self.inner.request("tw_getDelegationContract", ()).await?;
+        Ok(response)
+    }
 }

eip7702-core/src/constants.rs

@@ -1,8 +1,9 @@
 use alloy::primitives::{Address, address};
 
-/// The minimal account implementation address used for EIP-7702 delegation
-pub const MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS: Address =
-    address!("0xD6999651Fc0964B9c6B444307a0ab20534a66560");
+// The minimal account implementation address used for EIP-7702 delegation
+// pub const MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS: Address =
+//     address!("0xD6999651Fc0964B9c6B444307a0ab20534a66560");
+// NOTE!: do not hardcode. If needed later, use tw_getDelegationContract
 
 /// EIP-7702 delegation prefix bytes
 pub const EIP_7702_DELEGATION_PREFIX: [u8; 3] = [0xef, 0x01, 0x00];

eip7702-core/src/delegated_account.rs

@@ -10,10 +10,7 @@ use engine_core::{
 };
 use rand::Rng;
 
-use crate::constants::{
-    EIP_7702_DELEGATION_CODE_LENGTH, EIP_7702_DELEGATION_PREFIX,
-    MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS,
-};
+use crate::constants::{EIP_7702_DELEGATION_CODE_LENGTH, EIP_7702_DELEGATION_PREFIX};
 
 /// Represents an EOA address that can have EIP-7702 delegation, associated with a specific chain
 #[derive(Clone, Debug)]
@@ -62,21 +59,26 @@ impl<C: Chain> DelegatedAccount<C> {
 
         // Extract the target address from bytes 3-23 (20 bytes for address)
         // EIP-7702 format: 0xef0100 + 20 bytes address
-        let target_bytes = &code[3..23];
-        let target_address = Address::from_slice(target_bytes);
 
-        // Compare with the minimal account implementation address
-        let is_delegated = target_address == MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS;
+        // NOTE!: skip the actual delegated target address check for now
+        // extremely unlikely that an EOA being used with engine is delegated to a non-minimal account
+        // Potential source for fringe edge cases, please verify delegated target address if debugging 7702 execution issues
 
-        tracing::debug!(
-            eoa_address = ?self.eoa_address,
-            target_address = ?target_address,
-            minimal_account_address = ?MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS,
-            has_delegation = is_delegated,
-            "EIP-7702 delegation check result"
-        );
+        // let target_bytes = &code[3..23];
+        // let target_address = Address::from_slice(target_bytes);
+
+        // // Compare with the minimal account implementation address
+        // let is_delegated = target_address == MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS;
+
+        // tracing::debug!(
+        //     eoa_address = ?self.eoa_address,
+        //     target_address = ?target_address,
+        //     minimal_account_address = ?MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS,
+        //     has_delegation = is_delegated,
+        //     "EIP-7702 delegation check result"
+        // );
 
-        Ok(is_delegated)
+        Ok(true)
     }
 
     /// Get the EOA address
@@ -103,6 +105,7 @@ impl<C: Chain> DelegatedAccount<C> {
         &self,
         eoa_signer: &S,
         credentials: &SigningCredential,
+        delegation_contract: Address,
     ) -> Result<alloy::eips::eip7702::SignedAuthorization, EngineError> {
         let nonce = self.get_nonce().await?;
 
@@ -115,7 +118,7 @@ impl<C: Chain> DelegatedAccount<C> {
             .sign_authorization(
                 signing_options,
                 self.chain.chain_id(),
-                MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS,
+                delegation_contract,
                 nonce,
                 credentials,
             )

eip7702-core/src/transaction.rs

@@ -193,12 +193,13 @@ impl<C: Chain> MinimalAccountTransaction<C> {
         mut self,
         signer: &S,
         credentials: &SigningCredential,
+        delegation_contract: Address,
     ) -> Result<Self, EngineError> {
         if self.account.is_minimal_account().await? {
             return Ok(self);
         }
 
-        let authorization = self.account.sign_authorization(signer, credentials).await?;
+        let authorization = self.account.sign_authorization(signer, credentials, delegation_contract).await?;
         self.authorization = Some(authorization);
         Ok(self)
     }

eip7702-core/tests/integration_tests.rs

@@ -27,7 +27,6 @@ use engine_core::{
     transaction::InnerTransaction,
 };
 use engine_eip7702_core::{
-    constants::MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS,
     delegated_account::DelegatedAccount,
     transaction::{CallSpec, LimitType, SessionSpec, WrappedCalls},
 };
@@ -290,6 +289,7 @@ struct TestSetup {
     user_address: Address,
 
     signer: MockEoaSigner,
+    delegation_contract: Option<Address>,
 }
 
 const ANVIL_PORT: u16 = 8545;
@@ -358,6 +358,7 @@ impl TestSetup {
             signer,
             mock_erc20_contract: contract,
             anvil_provider: provider,
+            delegation_contract: None,
         })
     }
 
@@ -376,22 +377,32 @@ impl TestSetup {
         Ok(())
     }
 
-    async fn fetch_and_set_bytecode(&self) -> Result<(), Box<dyn std::error::Error>> {
+    async fn fetch_and_set_bytecode(&mut self) -> Result<(), Box<dyn std::error::Error>> {
         // Fetch bytecode from Base Sepolia
         let base_sepolia_url = "https://84532.rpc.thirdweb.com".parse()?;
         let base_sepolia_provider = ProviderBuilder::new().connect_http(base_sepolia_url);
 
+        let delegation_contract_response = self
+            .chain
+            .bundler_client()
+            .tw_get_delegation_contract()
+            .await?;
+
+        // Store the delegation contract address for later use
+        self.delegation_contract = Some(delegation_contract_response.delegation_contract);
+
         let bytecode = base_sepolia_provider
-            .get_code_at(MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS)
+            .get_code_at(delegation_contract_response.delegation_contract)
             .await?;
         // Set bytecode on our Anvil chain
         let _: () = self
             .anvil_provider
-            .anvil_set_code(MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS, bytecode)
+            .anvil_set_code(delegation_contract_response.delegation_contract, bytecode)
             .await?;
 
         println!(
-            "Set bytecode for minimal account implementation at {MINIMAL_ACCOUNT_IMPLEMENTATION_ADDRESS}"
+            "Set bytecode for minimal account implementation at {:?}",
+            delegation_contract_response.delegation_contract
         );
 
         Ok(())
@@ -645,7 +656,7 @@ impl TestSetup {
 #[tokio::test]
 async fn test_eip7702_integration() -> Result<(), Box<dyn std::error::Error>> {
     // Set up test environment
-    let setup = TestSetup::new().await?;
+    let mut setup = TestSetup::new().await?;
 
     // Step 1: Fetch and set bytecode from Base Sepolia
     setup.fetch_and_set_bytecode().await?;
@@ -683,7 +694,11 @@ async fn test_eip7702_integration() -> Result<(), Box<dyn std::error::Error>> {
     let developer_tx = developer_account
         .clone()
         .owner_transaction(&[mint_transaction])
-        .add_authorization_if_needed(&setup.signer, &setup.developer_credentials)
+        .add_authorization_if_needed(
+            &setup.signer, 
+            &setup.developer_credentials,
+            setup.delegation_contract.expect("Delegation contract should be set")
+        )
         .await?;
 
     let (wrapped_calls_json, signature) = developer_tx
@@ -723,7 +738,11 @@ async fn test_eip7702_integration() -> Result<(), Box<dyn std::error::Error>> {
     // Step 8: Delegate user account (session key granter)
     // User signs authorization but executor broadcasts it (user has no funds)
     let user_authorization = user_account
-        .sign_authorization(&setup.signer, &setup.user_credentials)
+        .sign_authorization(
+            &setup.signer, 
+            &setup.user_credentials,
+            setup.delegation_contract.expect("Delegation contract should be set")
+        )
         .await?;
 
     // Executor broadcasts the user's delegation transaction

executors/src/eip7702_executor/delegation_cache.rs

@@ -0,0 +1,68 @@
+use std::{ops::Deref, sync::Arc};
+
+use alloy::primitives::Address;
+use engine_core::{
+    chain::Chain,
+    error::{AlloyRpcErrorToEngineError, EngineError},
+    rpc_clients::TwGetDelegationContractResponse,
+};
+use moka::future::Cache;
+
+/// Cache key for delegation contract - uses chain_id as the key since each chain has one delegation contract
+#[derive(Hash, Eq, PartialEq, Clone, Debug)]
+pub struct DelegationContractCacheKey {
+    chain_id: u64,
+}
+
+/// Cache for delegation contract addresses to avoid repeated RPC calls
+#[derive(Clone)]
+pub struct DelegationContractCache {
+    pub inner: moka::future::Cache<DelegationContractCacheKey, Address>,
+}
+
+impl DelegationContractCache {
+    /// Create a new delegation contract cache with the provided moka cache
+    pub fn new(cache: Cache<DelegationContractCacheKey, Address>) -> Self {
+        Self { inner: cache }
+    }
+
+    /// Get the delegation contract address for a chain, fetching it if not cached
+    pub async fn get_delegation_contract<C: Chain>(
+        &self,
+        chain: &C,
+    ) -> Result<Address, EngineError> {
+        let cache_key = DelegationContractCacheKey {
+            chain_id: chain.chain_id(),
+        };
+
+        // Use try_get_with for SWR behavior - this will fetch if not cached or expired
+        let result = self
+            .inner
+            .try_get_with(cache_key, async {
+                tracing::debug!(
+                    chain_id = chain.chain_id(),
+                    "Fetching delegation contract from bundler"
+                );
+
+                let TwGetDelegationContractResponse {
+                    delegation_contract,
+                } = chain
+                    .bundler_client()
+                    .tw_get_delegation_contract()
+                    .await
+                    .map_err(|e| e.to_engine_bundler_error(chain))?;
+
+                tracing::debug!(
+                    chain_id = chain.chain_id(),
+                    delegation_contract = ?delegation_contract,
+                    "Successfully fetched and cached delegation contract"
+                );
+
+                Ok(delegation_contract)
+            })
+            .await
+            .map_err(|e: Arc<EngineError>| e.deref().clone())?;
+
+        Ok(result)
+    }
+}

executors/src/eip7702_executor/mod.rs

@@ -1,2 +1,3 @@
 pub mod send;
-pub mod confirm;
+pub mod confirm;
+pub mod delegation_cache;

executors/src/eip7702_executor/send.rs

@@ -22,7 +22,11 @@ use twmq::{
 };
 
 use crate::{
-    metrics::{record_transaction_queued_to_sent, current_timestamp_ms, calculate_duration_seconds_from_twmq},
+    eip7702_executor::delegation_cache::DelegationContractCache,
+    metrics::{
+        calculate_duration_seconds_from_twmq, current_timestamp_ms,
+        record_transaction_queued_to_sent,
+    },
     transaction_registry::TransactionRegistry,
     webhook::{
         WebhookJobHandler,
@@ -138,6 +142,7 @@ where
     pub webhook_queue: Arc<Queue<WebhookJobHandler>>,
     pub confirm_queue: Arc<Queue<Eip7702ConfirmationHandler<CS>>>,
     pub transaction_registry: Arc<TransactionRegistry>,
+    pub delegation_contract_cache: DelegationContractCache,
 }
 
 impl<CS> ExecutorStage for Eip7702SendHandler<CS>
@@ -216,8 +221,20 @@ where
             None => account.owner_transaction(&job_data.transactions),
         };
 
+        // Get delegation contract from cache
+        let delegation_contract = self
+            .delegation_contract_cache
+            .get_delegation_contract(transactions.account().chain())
+            .await
+            .map_err(|e| Eip7702SendError::DelegationCheckFailed { inner_error: e })
+            .map_err_fail()?;
+
         let transactions = transactions
-            .add_authorization_if_needed(self.eoa_signer.deref(), &job_data.signing_credential)
+            .add_authorization_if_needed(
+                self.eoa_signer.deref(),
+                &job_data.signing_credential,
+                delegation_contract,
+            )
             .await
             .map_err(|e| {
                 let mapped_error = match e {
@@ -281,10 +298,11 @@ where
 
         tracing::debug!(transaction_id = ?transaction_id, "EIP-7702 transaction sent to bundler");
 
-                    // Record metrics: transaction queued to sent
-            let sent_timestamp = current_timestamp_ms();
-            let queued_to_sent_duration = calculate_duration_seconds_from_twmq(job.job.created_at, sent_timestamp);
-            record_transaction_queued_to_sent("eip7702", job_data.chain_id, queued_to_sent_duration);
+        // Record metrics: transaction queued to sent
+        let sent_timestamp = current_timestamp_ms();
+        let queued_to_sent_duration =
+            calculate_duration_seconds_from_twmq(job.job.created_at, sent_timestamp);
+        record_transaction_queued_to_sent("eip7702", job_data.chain_id, queued_to_sent_duration);
 
         let sender_details = match session_key_target_address {
             Some(target_address) => Eip7702Sender::SessionKey {