feat(anvil): add TipAboveFeeCap error (#4395)

Author: jxom

anvil/src/eth/backend/mem/mod.rs

@@ -2015,9 +2015,20 @@ impl TransactionValidator for Backend {
             return Err(InvalidTransactionError::NonceTooLow)
         }
 
-        if (env.cfg.spec_id as u8) >= (SpecId::LONDON as u8) && tx.gas_price() < env.block.basefee {
-            warn!(target: "backend", "max fee per gas={}, too low, block basefee={}",tx.gas_price(),  env.block.basefee);
-            return Err(InvalidTransactionError::FeeTooLow)
+        if (env.cfg.spec_id as u8) >= (SpecId::LONDON as u8) {
+            if tx.gas_price() < env.block.basefee {
+                warn!(target: "backend", "max fee per gas={}, too low, block basefee={}",tx.gas_price(),  env.block.basefee);
+                return Err(InvalidTransactionError::FeeTooLow)
+            }
+
+            if let (Some(max_priority_fee_per_gas), Some(max_fee_per_gas)) =
+                (tx.essentials().max_priority_fee_per_gas, tx.essentials().max_fee_per_gas)
+            {
+                if max_priority_fee_per_gas > max_fee_per_gas {
+                    warn!(target: "backend", "max priority fee per gas={}, too high, max fee per gas={}", max_priority_fee_per_gas, max_fee_per_gas);
+                    return Err(InvalidTransactionError::TipAboveFeeCap)
+                }
+            }
         }
 
         let max_cost = tx.max_cost();

anvil/src/eth/error.rs

@@ -144,6 +144,11 @@ pub enum InvalidTransactionError {
     #[error("max fee per gas less than block base fee")]
     FeeTooLow,
 
+    /// Thrown to ensure no one is able to specify a transaction with a tip higher than the total
+    /// fee cap.
+    #[error("max priority fee per gas higher than max fee per gas")]
+    TipAboveFeeCap,
+
     /// Thrown when a tx was signed with a different chain_id
     #[error("invalid chain id for signer")]
     InvalidChainId,

anvil/tests/it/gas.rs

@@ -3,7 +3,10 @@
 use anvil::{eth::fees::INITIAL_BASE_FEE, spawn, NodeConfig};
 use ethers::{
     prelude::Middleware,
-    types::{transaction::eip2718::TypedTransaction, Address, BlockNumber, TransactionRequest},
+    types::{
+        transaction::eip2718::TypedTransaction, Address, BlockNumber, Eip1559TransactionRequest,
+        TransactionRequest,
+    },
 };
 
 const GAS_TRANSFER: u64 = 21_000u64;
@@ -87,3 +90,23 @@ async fn test_respect_base_fee() {
     let tx = provider.send_transaction(tx, None).await.unwrap().await.unwrap().unwrap();
     assert_eq!(tx.status, Some(1u64.into()));
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn test_tip_above_fee_cap() {
+    let base_fee = 50u64;
+    let (_api, handle) = spawn(NodeConfig::test().with_base_fee(Some(base_fee))).await;
+    let provider = handle.http_provider();
+    let tx = TypedTransaction::Eip1559(
+        Eip1559TransactionRequest::new()
+            .max_fee_per_gas(base_fee)
+            .max_priority_fee_per_gas(base_fee + 1)
+            .to(Address::random())
+            .value(100u64),
+    );
+    let res = provider.send_transaction(tx, None).await;
+    assert!(res.is_err());
+    assert!(res
+        .unwrap_err()
+        .to_string()
+        .contains("max priority fee per gas higher than max fee per gas"));
+}