Strip redundant EIP-7702 authorizations (#104)

* Strip redundant EIP-7702 authorizations

Add logic to filter out signed EIP-7702 authorizations that are already delegated to the target contract. Introduces a helper (filter_already_delegated_authorizations) which queries the account code, detects an existing delegation via EIP-7702 prefix/length, extracts the delegation target, and removes any matching authorizations from the list. This prevents RPC-level rejections on strict chains (e.g. Etherlink) caused by sending stale/redundant authorizations. The build path now uses the filtered list and only attaches an authorization_list if non-empty; provider lookup failures are logged and result in leaving the list unchanged.

* nit

Author: 0xFirekeeper

executors/src/eoa/worker/transaction.rs

@@ -12,8 +12,9 @@ use alloy::{
     consensus::{
         SignableTransaction, Signed, TxEip4844Variant, TxEip4844WithSidecar, TypedTransaction,
     },
+    eips::eip7702::SignedAuthorization,
     network::{TransactionBuilder, TransactionBuilder7702},
-    primitives::{Bytes, U256},
+    primitives::{Address, Bytes, U256},
     providers::Provider,
     rpc::types::TransactionRequest as AlloyTransactionRequest,
     signers::Signature,
@@ -26,6 +27,7 @@ use engine_core::{
     signer::{AccountSigner, EoaSigningOptions},
     transaction::TransactionTypeData,
 };
+use engine_eip7702_core::constants::{EIP_7702_DELEGATION_CODE_LENGTH, EIP_7702_DELEGATION_PREFIX};
 
 use crate::eoa::{
     EoaTransactionRequest,
@@ -249,6 +251,63 @@ impl<C: Chain> EoaExecutorWorker<C> {
         }
     }
 
+    /// Filter out authorization list entries where the authority is already delegated
+    /// to the target contract. This prevents Etherlink (and potentially other strict chains)
+    /// from rejecting type-4 transactions that include redundant/stale authorizations.
+    ///
+    /// On most chains, a stale authorization is simply skipped. On Etherlink, the entire
+    /// transaction is rejected at the RPC level, causing it to be silently dropped.
+    async fn filter_already_delegated_authorizations(
+        &self,
+        authorization_list: &[SignedAuthorization],
+        to: Option<Address>,
+    ) -> Vec<SignedAuthorization> {
+        // If we have a `to` address, check if it's already delegated to any of the
+        // authorization targets. In the 7702 relayer flow, `to` is the user's smart
+        // account and the authorization targets the delegation contract.
+        if let Some(account_address) = to {
+            match self.chain.provider().get_code_at(account_address).await {
+                Ok(code) => {
+                    let prefix_len = EIP_7702_DELEGATION_PREFIX.len();
+                    if code.len() >= EIP_7702_DELEGATION_CODE_LENGTH
+                        && code.starts_with(&EIP_7702_DELEGATION_PREFIX)
+                    {
+                        let delegated_to = Address::from_slice(&code[prefix_len..prefix_len + 20]);
+
+                        // Filter out any auth entries whose target matches the existing delegation
+                        let filtered: Vec<_> = authorization_list
+                            .iter()
+                            .filter(|auth| {
+                                if auth.address == delegated_to {
+                                    tracing::info!(
+                                        account = ?account_address,
+                                        delegation_target = ?delegated_to,
+                                        "Stripping redundant authorization - account already delegated to target"
+                                    );
+                                    false
+                                } else {
+                                    true
+                                }
+                            })
+                            .cloned()
+                            .collect();
+
+                        return filtered;
+                    }
+                }
+                Err(e) => {
+                    tracing::warn!(
+                        account = ?account_address,
+                        error = ?e,
+                        "Failed to check delegation status, keeping all authorizations"
+                    );
+                }
+            }
+        }
+
+        authorization_list.to_vec()
+    }
+
     pub async fn build_typed_transaction(
         &self,
         request: &EoaTransactionRequest,
@@ -301,7 +360,12 @@ impl<C: Chain> EoaExecutorWorker<C> {
                 TransactionTypeData::Eip7702(data) => {
                     let mut req = tx_request;
                     if let Some(authorization_list) = &data.authorization_list {
-                        req = req.with_authorization_list(authorization_list.clone());
+                        let filtered = self
+                            .filter_already_delegated_authorizations(authorization_list, request.to)
+                            .await;
+                        if !filtered.is_empty() {
+                            req = req.with_authorization_list(filtered);
+                        }
                     }
                     if let Some(max_fee) = data.max_fee_per_gas {
                         req = req.with_max_fee_per_gas(max_fee);