fix: emit hashed message in evm fill events

contracts/SpokePool.sol

@@ -1127,7 +1127,7 @@ abstract contract SpokePool is
             relayData.exclusiveRelayer,
             relayData.depositor,
             relayData.recipient,
-            relayData.message
+            _hashNonEmptyMessage(relayData.message)
         );
     }
 
@@ -1711,10 +1711,10 @@ abstract contract SpokePool is
             relayer,
             relayData.depositor,
             relayData.recipient,
-            relayData.message,
+            _hashNonEmptyMessage(relayData.message),
             V3RelayExecutionEventInfo({
                 updatedRecipient: relayExecution.updatedRecipient,
-                updatedMessage: relayExecution.updatedMessage,
+                updatedMessageHash: _hashNonEmptyMessage(relayExecution.updatedMessage),
                 updatedOutputAmount: relayExecution.updatedOutputAmount,
                 fillType: fillType
             })
@@ -1764,6 +1764,12 @@ abstract contract SpokePool is
         return exclusivityDeadline >= currentTime;
     }
 
+    // Helper for emitting message hash. For easier easier human readability we return bytes32(0) for empty message.
+    function _hashNonEmptyMessage(bytes memory message) internal pure returns (bytes32) {
+        if (message.length == 0) return bytes32(0);
+        else return keccak256(message);
+    }
+
     // Implementing contract needs to override this to ensure that only the appropriate cross chain admin can execute
     // certain admin functions. For L2 contracts, the cross chain admin refers to some L1 address or contract, and for
     // L1, this would just be the same admin of the HubPool.

contracts/interfaces/V3SpokePoolInterface.sol

@@ -87,7 +87,7 @@ interface V3SpokePoolInterface {
     // filled so they don't have to be unpacked by all clients.
     struct V3RelayExecutionEventInfo {
         bytes32 updatedRecipient;
-        bytes updatedMessage;
+        bytes32 updatedMessageHash;
         uint256 updatedOutputAmount;
         FillType fillType;
     }
@@ -152,7 +152,7 @@ interface V3SpokePoolInterface {
         bytes32 indexed relayer,
         bytes32 depositor,
         bytes32 recipient,
-        bytes message,
+        bytes32 messageHash,
         V3RelayExecutionEventInfo relayExecutionInfo
     );
 
@@ -168,7 +168,7 @@ interface V3SpokePoolInterface {
         bytes32 exclusiveRelayer,
         bytes32 depositor,
         bytes32 recipient,
-        bytes message
+        bytes32 messageHash
     );
 
     event ClaimedRelayerRefund(

programs/svm-spoke/src/state/instruction_params.rs

@@ -8,5 +8,5 @@ pub struct ExecuteRelayerRefundLeafParams {
     pub root_bundle_id: u32,                    // ID of the root bundle to be used.
     pub relayer_refund_leaf: RelayerRefundLeaf, // Leaf to be verified against the proof and instruct bundle execution.
     #[max_len(0)]
-    pub proof: Vec<[u8; 32]>, // Proof to verify the leaf's inclusion in relayer refund merkle tree.
+    pub proof: Vec<[u8; 32]>,  // Proof to verify the leaf's inclusion in relayer refund merkle tree.
 }

test/evm/hardhat/SpokePool.Relay.ts

@@ -10,6 +10,7 @@ import {
   BigNumber,
   addressToBytes,
   bytes32ToAddress,
+  hashNonEmptyMessage,
 } from "../../../utils/utils";
 import {
   spokePoolFixture,
@@ -130,10 +131,10 @@ describe("SpokePool Relayer Logic", async function () {
             addressToBytes(relayer.address),
             addressToBytes(relayData.depositor),
             addressToBytes(relayData.recipient),
-            relayData.message,
+            hashNonEmptyMessage(relayData.message),
             [
               addressToBytes(relayData.recipient),
-              relayExecution.updatedMessage,
+              hashNonEmptyMessage(relayExecution.updatedMessage),
               relayExecution.updatedOutputAmount,
               // Testing that this FillType is not "FastFill"
               FillType.ReplacedSlowFill,
@@ -166,10 +167,10 @@ describe("SpokePool Relayer Logic", async function () {
             addressToBytes(relayer.address),
             addressToBytes(relayData.depositor),
             addressToBytes(relayData.recipient),
-            relayData.message,
+            hashNonEmptyMessage(relayData.message),
             [
               addressToBytes(relayData.recipient),
-              relayExecution.updatedMessage,
+              hashNonEmptyMessage(relayExecution.updatedMessage),
               relayExecution.updatedOutputAmount,
               // Testing that this FillType is "SlowFill"
               FillType.SlowFill,
@@ -201,10 +202,10 @@ describe("SpokePool Relayer Logic", async function () {
             addressToBytes(relayer.address),
             addressToBytes(relayData.depositor),
             addressToBytes(relayData.recipient),
-            relayData.message,
+            hashNonEmptyMessage(relayData.message),
             [
               addressToBytes(relayData.recipient),
-              relayExecution.updatedMessage,
+              hashNonEmptyMessage(relayExecution.updatedMessage),
               relayExecution.updatedOutputAmount,
               FillType.FastFill,
             ]
@@ -372,10 +373,10 @@ describe("SpokePool Relayer Logic", async function () {
             addressToBytes(relayer.address), // Should be equal to msg.sender of fillRelayV3
             addressToBytes(relayData.depositor),
             addressToBytes(relayData.recipient),
-            relayData.message,
+            hashNonEmptyMessage(relayData.message),
             [
               addressToBytes(relayData.recipient), // updatedRecipient should be equal to recipient
-              relayData.message, // updatedMessage should be equal to message
+              hashNonEmptyMessage(relayData.message), // updatedMessageHash should be equal to message hash
               relayData.outputAmount, // updatedOutputAmount should be equal to outputAmount
               // Should be FastFill
               FillType.FastFill,
@@ -487,11 +488,11 @@ describe("SpokePool Relayer Logic", async function () {
             addressToBytes(relayer.address), // Should be equal to msg.sender
             addressToBytes(relayData.depositor),
             addressToBytes(relayData.recipient),
-            relayData.message,
+            hashNonEmptyMessage(relayData.message),
             [
               // Should use passed-in updated params:
               addressToBytes(updatedRecipient),
-              updatedMessage,
+              hashNonEmptyMessage(updatedMessage),
               updatedOutputAmount,
               // Should be FastFill
               FillType.FastFill,

test/evm/hardhat/SpokePool.SlowRelay.ts

@@ -7,6 +7,7 @@ import {
   seedContract,
   seedWallet,
   addressToBytes,
+  hashNonEmptyMessage,
 } from "../../../utils/utils";
 import { spokePoolFixture, V3RelayData, getV3RelayHash, V3SlowFill, FillType } from "./fixtures/SpokePool.Fixture";
 import { buildV3SlowRelayTree } from "./MerkleLib.utils";
@@ -309,12 +310,12 @@ describe("SpokePool Slow Relay Logic", async function () {
           addressToBytes(consts.zeroAddress), // Sets relayer address to 0x0
           addressToBytes(relayData.depositor),
           addressToBytes(relayData.recipient),
-          relayData.message,
+          hashNonEmptyMessage(relayData.message),
           [
             // Uses relayData.recipient
             addressToBytes(relayData.recipient),
             // Uses relayData.message
-            relayData.message,
+            hashNonEmptyMessage(relayData.message),
             // Uses slow fill leaf's updatedOutputAmount
             slowRelayLeaf.updatedOutputAmount,
             // Should be SlowFill

utils/utils.ts

@@ -192,6 +192,16 @@ export function trimSolanaAddress(bytes32Address: string): string {
   return ethers.utils.hexZeroPad(ethers.utils.hexlify(uint160Address), 20);
 }
 
+export function hashNonEmptyMessage(message: string) {
+  if (!ethers.utils.isHexString(message) || message.length % 2 !== 0) throw new Error("Invalid hex message bytes");
+
+  // account for 0x prefix when checking length
+  if (message.length > 2) {
+    return ethers.utils.keccak256(message);
+  }
+  return ethers.utils.hexlify(new Uint8Array(32));
+}
+
 const { defaultAbiCoder, keccak256 } = ethers.utils;
 
 export { avmL1ToL2Alias, expect, Contract, ethers, BigNumber, defaultAbiCoder, keccak256, FakeContract, Signer };