leave 1 wei in GS

consenlabs · Nov 30, 2023 · c7cdde6 · c7cdde6
1 parent 75449d1
commit c7cdde6
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/contracts/GenericSwap.sol b/contracts/GenericSwap.sol
@@ -67,16 +67,19 @@ contract GenericSwap is IGenericSwap, TokenCollector, EIP712 {
 
         if (_inputToken.isETH()) {
             if (msg.value != _swapData.takerTokenAmount) revert InvalidMsgValue();
-        }
-
-        if (!_inputToken.isETH()) {
+        } else {
             if (msg.value != 0) revert InvalidMsgValue();
             _collect(_inputToken, _authorizedUser, _swapData.maker, _swapData.takerTokenAmount, _takerTokenPermit);
         }
 
         IStrategy(_swapData.maker).executeStrategy{ value: msg.value }(_inputToken, _outputToken, _swapData.takerTokenAmount, _swapData.strategyData);
 
         returnAmount = _outputToken.getBalance(address(this));
+        if (returnAmount > 1) {
+            unchecked {
+                --returnAmount;
+            }
+        }
         if (returnAmount < _swapData.minMakerTokenAmount) revert InsufficientOutput();
 
         _outputToken.transferTo(_swapData.recipient, returnAmount);

diff --git a/test/forkMainnet/GenericSwap.t.sol b/test/forkMainnet/GenericSwap.t.sol
@@ -63,7 +63,10 @@ contract GenericSwapTest is Test, Tokens, BalanceUtil, Permit2Helper, SigHelper
         genericSwap = new GenericSwap(UNISWAP_PERMIT2_ADDRESS, address(allowanceTarget));
         smartStrategy = new SmartOrderStrategy(strategyAdmin, address(genericSwap), WETH_ADDRESS);
 
+        // deposit 1 wei in SOR and GS
         deal(DAI_ADDRESS, address(smartStrategy), 1 wei);
+        deal(DAI_ADDRESS, address(genericSwap), 1 wei);
+        deal(address(genericSwap), 1 wei);
 
         mockStrategy = new MockStrategy();
         vm.prank(strategyAdmin);