add error handling for zero swap amount in GenericSwap

Author: alex0207s

contracts/GenericSwap.sol

@@ -66,6 +66,7 @@ contract GenericSwap is IGenericSwap, TokenCollector, EIP712 {
     ) private returns (uint256 returnAmount) {
         if (_swapData.expiry < block.timestamp) revert ExpiredOrder();
         if (_swapData.recipient == address(0)) revert ZeroAddress();
+        if (_swapData.takerTokenAmount == 0) revert SwapWithZeroAmount();
 
         address _inputToken = _swapData.takerToken;
         address _outputToken = _swapData.makerToken;

contracts/interfaces/IGenericSwap.sol

@@ -54,6 +54,10 @@ interface IGenericSwap {
     /// @dev This error is used to ensure that a valid address is provided.
     error ZeroAddress();
 
+    /// @notice Error to be thrown when a swap amount is zero.
+    /// @dev This error is used to ensure that a valid, nonzero swap amount is provided.
+    error SwapWithZeroAmount();
+
     /// @notice Executes a swap using provided swap data and taker token permit.
     /// @param swapData The swap data containing details of the swap.
     /// @param takerTokenPermit The permit for spending taker's tokens.

snapshots/GenericSwap.json

@@ -1,9 +1,9 @@
 {
-  "executeSwap(): testGenericSwapWithUniswap": "248116",
-  "executeSwap(): testLeaveOneWeiWithMultipleUsers(the first deposit)": "248116",
-  "executeSwap(): testLeaveOneWeiWithMultipleUsers(the second deposit)": "204470",
-  "executeSwap(): testSwapWithETHInput": "97797",
-  "executeSwap(): testSwapWithETHOutput": "127948",
-  "executeSwap(): testSwapWithLessOutputButWithinTolerance": "157404",
-  "executeSwapWithSig(): testGenericSwapRelayed": "279447"
+  "executeSwap(): testGenericSwapWithUniswap": "248141",
+  "executeSwap(): testLeaveOneWeiWithMultipleUsers(the first deposit)": "248141",
+  "executeSwap(): testLeaveOneWeiWithMultipleUsers(the second deposit)": "204495",
+  "executeSwap(): testSwapWithETHInput": "97813",
+  "executeSwap(): testSwapWithETHOutput": "127973",
+  "executeSwap(): testSwapWithLessOutputButWithinTolerance": "157429",
+  "executeSwapWithSig(): testGenericSwapRelayed": "279472"
 }

test/forkMainnet/GenericSwap.t.sol

@@ -321,6 +321,16 @@ contract GenericSwapTest is Test, Tokens, BalanceUtil, Permit2Helper, SigHelper
         vm.stopPrank();
     }
 
+    function testCannotSwapWithZeroAmount() public {
+        GenericSwapData memory gsData = defaultGSData;
+        gsData.takerTokenAmount = 0;
+
+        vm.startPrank(taker);
+        vm.expectRevert(IGenericSwap.SwapWithZeroAmount.selector);
+        genericSwap.executeSwap(gsData, defaultTakerPermit);
+        vm.stopPrank();
+    }
+
     function testGenericSwapRelayed() public {
         Snapshot memory takerTakerToken = BalanceSnapshot.take({ owner: taker, token: defaultGSData.takerToken });
         Snapshot memory takerMakerToken = BalanceSnapshot.take({ owner: taker, token: defaultGSData.makerToken });