feat, test: round gas adjustments in favor of swapper

Uniswap · Oct 1, 2024 · 8dce531 · 8dce531
1 parent b0cd19a
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Showing 2 changed files with 56 additions and 4 deletions.
diff --git a/src/reactors/V3DutchOrderReactor.sol b/src/reactors/V3DutchOrderReactor.sol
@@ -112,15 +112,19 @@ contract V3DutchOrderReactor is BaseReactor {
         // positive means an increase in gas
         int256 gasDeltaGwei = block.basefee.sub(order.startingBaseFee);
 
-        // Gas increase should increase input
-        int256 inputDelta = int256(order.baseInput.adjustmentPerGweiBaseFee) * gasDeltaGwei / 1 gwei;
+        // Gas increase should increase input (round up when positive, down when negative)
+        int256 inputDelta = gasDeltaGwei >= 0
+            ? (int256(order.baseInput.adjustmentPerGweiBaseFee) * gasDeltaGwei + 1 gwei - 1) / 1 gwei
+            : (int256(order.baseInput.adjustmentPerGweiBaseFee) * gasDeltaGwei) / 1 gwei;
         order.baseInput.startAmount = order.baseInput.startAmount.boundedAdd(inputDelta, 0, order.baseInput.maxAmount);
 
-        // Gas increase should decrease output
+        // Gas increase should decrease output (round down when positive, up when negative)
         uint256 outputsLength = order.baseOutputs.length;
         for (uint256 i = 0; i < outputsLength; i++) {
             V3DutchOutput memory output = order.baseOutputs[i];
-            int256 outputDelta = int256(output.adjustmentPerGweiBaseFee) * gasDeltaGwei / 1 gwei;
+            int256 outputDelta = gasDeltaGwei >= 0
+                ? (int256(output.adjustmentPerGweiBaseFee) * gasDeltaGwei) / 1 gwei
+                : (int256(output.adjustmentPerGweiBaseFee) * gasDeltaGwei - 1 gwei + 1) / 1 gwei;
             output.startAmount = output.startAmount.boundedSub(outputDelta, output.minAmount, type(uint256).max);
         }
     }

diff --git a/test/reactors/V3DutchOrderReactor.t.sol b/test/reactors/V3DutchOrderReactor.t.sol
@@ -1401,6 +1401,54 @@ contract V3DutchOrderTest is PermitSignature, DeployPermit2, BaseReactorTest {
         assertEq(resolvedOrder.input.amount, 0);
     }
 
+    function testV3GasAdjustmentRounding() public {
+        uint256 currentBlock = 21212121;
+        vm.roll(currentBlock);
+        vm.fee(1 gwei);
+
+        // Order with 0.8 gwei gas adjustments
+        SignedOrder memory order = generateOrder(
+            TestDutchOrderSpec({
+                currentBlock: currentBlock,
+                startBlock: currentBlock,
+                deadline: currentBlock + 21,
+                input: V3DutchInput(tokenIn, 100 ether, CurveBuilder.emptyCurve(), 101 ether, 0.8 gwei),
+                outputs: OutputsBuilder.singleV3Dutch(
+                    V3DutchOutput(address(tokenOut), 100 ether, CurveBuilder.emptyCurve(), address(0), 99 ether, 0.8 gwei)
+                )
+            })
+        );
+
+        // Test gas increase
+        vm.fee(2 gwei);
+        ResolvedOrder memory resolvedOrder = quoter.quote(order.order, order.sig);
+        assertEq(resolvedOrder.input.amount, 100 ether + 0.8 gwei, "Input should round up for positive gas change");
+        assertEq(resolvedOrder.outputs[0].amount, 100 ether - 0.8 gwei, "Output should round down for positive gas change");
+
+        // Test gas decrease
+        vm.fee(0.5 gwei);
+        resolvedOrder = quoter.quote(order.order, order.sig);
+        assertEq(resolvedOrder.input.amount, 100 ether - 0.4 gwei, "Input should round down for negative gas change");
+        assertEq(resolvedOrder.outputs[0].amount, 100 ether + 0.4 gwei, "Output should round up for negative gas change");
+
+        // Test gas half
+        vm.fee(0.5 gwei);
+        resolvedOrder = quoter.quote(order.order, order.sig);
+        assertEq(resolvedOrder.input.amount, 100 ether - 0.4 gwei, "Input should round down for gas halving change");
+        assertEq(resolvedOrder.outputs[0].amount, 100 ether + 0.4 gwei, "Output should round up for exact gas halving change");
+
+        // Test smaller gas changes
+        vm.fee(1.1 gwei);
+        resolvedOrder = quoter.quote(order.order, order.sig);
+        assertEq(resolvedOrder.input.amount, 100 ether + 0.08 gwei, "Input should handle small positive gas changes");
+        assertEq(resolvedOrder.outputs[0].amount, 100 ether - 0.08 gwei, "Output should handle small positive gas changes");
+
+        vm.fee(0.9 gwei);
+        resolvedOrder = quoter.quote(order.order, order.sig);
+        assertEq(resolvedOrder.input.amount, 100 ether - 0.08 gwei, "Input should handle small negative gas changes");
+        assertEq(resolvedOrder.outputs[0].amount, 100 ether + 0.08 gwei, "Output should handle small negative gas changes");
+    }
+
     /* Test helpers */
 
     struct TestDutchOrderSpec {