require that returned lzTokenFee is zero. Add tests for fee cap checking (#1029)

Signed-off-by: Ihor Farion <ihor@umaproject.org>

Author: grasphoper

contracts/libraries/OFTTransportAdapter.sol

@@ -33,6 +33,7 @@ contract OFTTransportAdapter {
 
     error OftFeeCapExceeded();
     error OftInsufficientBalanceForFee();
+    error OftLzFeeNotZero();
     error OftIncorrectAmountReceivedLD();
     error OftIncorrectAmountSentLD();
 
@@ -88,6 +89,7 @@ contract OFTTransportAdapter {
         uint256 nativeFee = fee.nativeFee;
         if (nativeFee > OFT_FEE_CAP) revert OftFeeCapExceeded();
         if (nativeFee > address(this).balance) revert OftInsufficientBalanceForFee();
+        if (fee.lzTokenFee != 0) revert OftLzFeeNotZero();
 
         // Approve the exact _amount for `_messenger` to spend. Fee will be paid in native token
         _token.forceApprove(address(_messenger), _amount);

contracts/test/MockOFTMessenger.sol

@@ -10,13 +10,21 @@ import "../interfaces/IOFT.sol";
  */
 contract MockOFTMessenger is IOFT {
     address public token;
+    uint256 nativeFee;
+    uint256 lzFee;
 
-    constructor(address _token) {
+    constructor(
+        address _token,
+        uint256 _nativeFee,
+        uint256 _lzFee
+    ) {
         token = _token;
+        nativeFee = _nativeFee;
+        lzFee = _lzFee;
     }
 
     function quoteSend(SendParam calldata _sendParam, bool _payInLzToken) external view returns (MessagingFee memory) {
-        return MessagingFee(0, 0);
+        return MessagingFee(nativeFee, lzFee);
     }
 
     function send(

test/evm/foundry/local/Universal_Adapter.t.sol

@@ -12,6 +12,7 @@ import { AdapterStore, MessengerTypes } from "../../../../contracts/AdapterStore
 import { IOFT, SendParam, MessagingFee } from "../../../../contracts/interfaces/IOFT.sol";
 import { MockOFTMessenger } from "../../../../contracts/test/MockOFTMessenger.sol";
 import { AddressToBytes32 } from "../../../../contracts/libraries/AddressConverters.sol";
+import { OFTTransportAdapter } from "../../../../contracts/libraries/OFTTransportAdapter.sol";
 
 contract UniversalAdapterTest is Test {
     using AddressToBytes32 for address;
@@ -23,7 +24,6 @@ contract UniversalAdapterTest is Test {
     uint256 relayRootBundleNonce = 0;
     address relayRootBundleTargetAddress = address(0);
     AdapterStore adapterStore;
-    IOFT oftMessenger;
     ERC20 usdc;
     ERC20 usdt;
     uint256 usdcMintAmount = 100e6;
@@ -57,8 +57,6 @@ contract UniversalAdapterTest is Test {
         store = new HubPoolStore(address(hubPool));
         usdc = new ERC20("USDC", "USDC");
         usdt = new ERC20("USDT", "USDT");
-        oftMessenger = IOFT(new MockOFTMessenger(address(usdt)));
-        adapterStore.setMessenger(MessengerTypes.OFT_MESSENGER, oftDstEid, address(usdt), address(oftMessenger));
         MockCCTPMinter minter = new MockCCTPMinter();
         cctpMessenger = new MockCCTPMessenger(ITokenMinter(minter));
         adapter = new Universal_Adapter(
@@ -273,6 +271,11 @@ contract UniversalAdapterTest is Test {
     }
 
     function testRelayTokens_oft() public {
+        vm.startPrank(owner);
+        IOFT oftMessenger = IOFT(new MockOFTMessenger(address(usdt), 0, 0));
+        adapterStore.setMessenger(MessengerTypes.OFT_MESSENGER, oftDstEid, address(usdt), address(oftMessenger));
+        vm.stopPrank();
+
         // Uses OFT to send USDT
         vm.expectCall(
             address(oftMessenger),
@@ -296,6 +299,47 @@ contract UniversalAdapterTest is Test {
         hubPool.relayTokens(address(usdt), makeAddr("l2Usdt"), usdcMintAmount, spokePoolTarget);
     }
 
+    function testNonZeroLzFee() public {
+        vm.startPrank(owner);
+        // Mock an OFT messenger that returns a non-zero lzTokenFee
+        IOFT oftMessengerWithNonZeroLzFee = IOFT(new MockOFTMessenger(address(usdt), 0, 1)); // nativeFee = 0, lzFee = 1
+        adapterStore.setMessenger(
+            MessengerTypes.OFT_MESSENGER,
+            oftDstEid,
+            address(usdt),
+            address(oftMessengerWithNonZeroLzFee)
+        );
+        vm.stopPrank();
+
+        // Expect the OftLzFeeNotZero error from OFTTransportAdapter logic within Universal_Adapter
+        // This will be caught by HubPool and re-thrown. Due to `revert_strings = "strip"`,
+        // HubPool's require(..., "string") will revert with no data.
+        vm.expectRevert();
+        hubPool.relayTokens(address(usdt), makeAddr("l2Usdt"), usdcMintAmount, spokePoolTarget);
+    }
+
+    function testFeeTooHigh() public {
+        // Determine a native fee that is higher than the adapter's OFT_FEE_CAP
+        uint256 highNativeFee = adapter.OFT_FEE_CAP() + 1;
+        MockOFTMessenger oftMessengerWithHighFee = new MockOFTMessenger(address(usdt), highNativeFee, 0); // nativeFee > OFT_FEE_CAP, lzFee = 0
+        vm.startPrank(owner);
+        adapterStore.setMessenger(
+            MessengerTypes.OFT_MESSENGER,
+            oftDstEid,
+            address(usdt),
+            address(oftMessengerWithHighFee)
+        );
+        vm.stopPrank();
+
+        deal(address(hubPool), adapter.OFT_FEE_CAP());
+
+        // Expect the OftFeeCapExceeded error from OFTTransportAdapter logic within Universal_Adapter
+        // This will be caught by HubPool and re-thrown. Due to `revert_strings = "strip"`,
+        // HubPool's require(..., "string") will revert with no data.
+        vm.expectRevert();
+        hubPool.relayTokens(address(usdt), makeAddr("l2Usdt"), usdcMintAmount, spokePoolTarget);
+    }
+
     function testRelayTokens_default() public {
         vm.expectRevert();
         hubPool.relayTokens(makeAddr("erc20"), makeAddr("l2Erc20"), usdcMintAmount, spokePoolTarget);

test/evm/foundry/local/Universal_SpokePool.t.sol

@@ -11,6 +11,7 @@ import "../../../../contracts/test/MockCCTP.sol";
 import { IOFT, SendParam, MessagingFee } from "../../../../contracts/interfaces/IOFT.sol";
 import { MockOFTMessenger } from "../../../../contracts/test/MockOFTMessenger.sol";
 import { AddressToBytes32 } from "../../../../contracts/libraries/AddressConverters.sol";
+import { OFTTransportAdapter } from "../../../../contracts/libraries/OFTTransportAdapter.sol";
 
 contract MockHelios is IHelios {
     mapping(bytes32 => bytes32) public storageSlots;
@@ -70,7 +71,6 @@ contract UniversalSpokePoolTest is Test {
     using AddressToBytes32 for address;
     MockUniversalSpokePool spokePool;
     MockHelios helios;
-    IOFT oftMessenger;
 
     address hubPoolStore;
     address hubPool;
@@ -111,7 +111,6 @@ contract UniversalSpokePoolTest is Test {
             new ERC1967Proxy(address(spokePool), abi.encodeCall(Universal_SpokePool.initialize, (0, hubPool, hubPool)))
         );
         spokePool = MockUniversalSpokePool(payable(proxy));
-        oftMessenger = IOFT(new MockOFTMessenger(address(usdt)));
         deal(address(usdc), address(spokePool), usdcMintAmount, true);
     }
 
@@ -294,6 +293,7 @@ contract UniversalSpokePoolTest is Test {
     }
 
     function testSetOftMessenger() public {
+        IOFT oftMessenger = IOFT(new MockOFTMessenger(address(usdt), 0, 0));
         bytes memory message = abi.encodeWithSignature(
             "setOftMessenger(address,address)",
             address(usdt),
@@ -305,7 +305,53 @@ contract UniversalSpokePoolTest is Test {
         assertEq(spokePool.oftMessengers(address(usdt)), address(oftMessenger));
     }
 
+    function testNonZeroLzFee() public {
+        // Mock an OFT messenger that returns a non-zero lzTokenFee
+        MockOFTMessenger oftMessengerWithNonZeroLzFee = new MockOFTMessenger(address(usdt), 0, 1); // nativeFee = 0, lzFee = 1
+
+        // Set this messenger for USDT
+        bytes memory message = abi.encodeWithSignature(
+            "setOftMessenger(address,address)",
+            address(usdt),
+            address(oftMessengerWithNonZeroLzFee)
+        );
+        bytes memory value = abi.encode(address(spokePool), message);
+        helios.updateStorageSlot(spokePool.getSlotKey(nonce), keccak256(value));
+        spokePool.executeMessage(nonce, value, 100);
+        nonce++; // Increment nonce for the next message
+
+        // Expect the OftLzFeeNotZero error from OFTTransportAdapter
+        vm.expectRevert(OFTTransportAdapter.OftLzFeeNotZero.selector);
+        spokePool.test_bridgeTokensToHubPool(usdcMintAmount, address(usdt));
+    }
+
+    function testFeeTooHigh() public {
+        // Mock an OFT messenger that returns a nativeFee higher than OFT_FEE_CAP
+        uint256 highNativeFee = spokePool.OFT_FEE_CAP() + 1;
+        MockOFTMessenger oftMessengerWithHighFee = new MockOFTMessenger(address(usdt), highNativeFee, 0); // nativeFee > OFT_FEE_CAP, lzFee = 0
+
+        // Set this messenger for USDT
+        bytes memory message = abi.encodeWithSignature(
+            "setOftMessenger(address,address)",
+            address(usdt),
+            address(oftMessengerWithHighFee)
+        );
+        bytes memory value = abi.encode(address(spokePool), message);
+        helios.updateStorageSlot(spokePool.getSlotKey(nonce), keccak256(value));
+        spokePool.executeMessage(nonce, value, 100);
+        nonce++; // Increment nonce for the next message
+
+        // Fund the spokePool with enough native currency to attempt the transaction but less than the high fee
+        // The check for OFT_FEE_CAP happens before the balance check.
+        deal(address(spokePool), spokePool.OFT_FEE_CAP());
+
+        // Expect the OftFeeCapExceeded error from OFTTransportAdapter
+        vm.expectRevert(OFTTransportAdapter.OftFeeCapExceeded.selector);
+        spokePool.test_bridgeTokensToHubPool(usdcMintAmount, address(usdt));
+    }
+
     function testBridgeTokensToHubPool_oft() public {
+        IOFT oftMessenger = IOFT(new MockOFTMessenger(address(usdt), 0, 0));
         bytes memory message = abi.encodeWithSignature(
             "setOftMessenger(address,address)",
             address(usdt),