fix: taking round down into consideration when calculates swap fee

.forge-snapshots/NonfungiblePositionManager#collect.snap

@@ -1 +1 @@
-196939
+199462

src/pool-cl/NonfungiblePositionManager.sol

@@ -436,6 +436,15 @@ contract NonfungiblePositionManager is
         nftPosition.tokensOwed0 = tokensOwed0 - amount0Collect;
         nftPosition.tokensOwed1 = tokensOwed1 - amount1Collect;
 
+        /// @dev due to rounding down calculation in FullMath, some wei might be loss if the fee is too small
+        /// if that happen we need to ignore the loss part and take the rest of the fee otherwise it will revert whole tx
+        uint128 actualFee0Left = uint128(vault.balanceOf(address(this), poolKey.currency0));
+        uint128 actualFee1Left = uint128(vault.balanceOf(address(this), poolKey.currency1));
+        (amount0Collect, amount1Collect) = (
+            actualFee0Left > amount0Collect ? amount0Collect : actualFee0Left,
+            actualFee1Left > amount1Collect ? amount1Collect : actualFee1Left
+        );
+
         // cash out from vault
         burnAndTake(poolKey.currency0, params.recipient, amount0Collect);
         burnAndTake(poolKey.currency1, params.recipient, amount1Collect);

test/pool-cl/CLSwapRouterInvariant.t.sol

@@ -47,6 +47,9 @@ contract CLSwapRouterHandler is Test {
     uint256 public token1Minted;
     uint256 public nativeTokenMinted;
 
+    uint256 public token0FeeAccrued;
+    uint256 public token1FeeAccrued;
+
     constructor() {
         WETH weth = new WETH();
         vault = new Vault();
@@ -110,6 +113,9 @@ contract CLSwapRouterHandler is Test {
         PoolKey memory pk = isNativePool ? nativePoolKey : poolKey;
         // if native pool, have to ensure call method with value
         uint256 value = isNativePool ? amtIn : 0;
+
+        vm.recordLogs();
+
         vm.prank(alice);
         router.exactInputSingle{value: value}(
             ICLSwapRouterBase.V4CLExactInputSingleParams({
@@ -123,6 +129,8 @@ contract CLSwapRouterHandler is Test {
             }),
             block.timestamp + 100
         );
+
+        _accumulateFee();
     }
 
     function exactSwapInput(uint128 amtIn, bool isNativePool) public {
@@ -138,7 +146,6 @@ contract CLSwapRouterHandler is Test {
 
         // Step 3: swap
         PoolKey memory pk = isNativePool ? nativePoolKey : poolKey;
-        vm.prank(alice);
         ISwapRouterBase.PathKey[] memory path = new ISwapRouterBase.PathKey[](1);
         path[0] = ISwapRouterBase.PathKey({
             intermediateCurrency: Currency.wrap(address(token1)),
@@ -149,8 +156,11 @@ contract CLSwapRouterHandler is Test {
             parameters: pk.parameters
         });
 
+        vm.recordLogs();
+
         // if native pool, have to ensure call method with value
         uint256 value = isNativePool ? amtIn : 0;
+        vm.prank(alice);
         router.exactInput{value: value}(
             ICLSwapRouterBase.V4CLExactInputParams({
                 currencyIn: isNativePool ? CurrencyLibrary.NATIVE : currency0,
@@ -161,6 +171,8 @@ contract CLSwapRouterHandler is Test {
             }),
             block.timestamp + 100
         );
+
+        _accumulateFee();
     }
 
     function exactSwapOutputSingle(uint128 amtIn, bool isNativePool) public {
@@ -174,6 +186,8 @@ contract CLSwapRouterHandler is Test {
         isNativePool ? nativeTokenMinted += amtIn : token0Minted += amtIn;
 
         // Step 3: swap
+        vm.recordLogs();
+
         PoolKey memory pk = isNativePool ? nativePoolKey : poolKey;
         // if native pool, have to ensure call method with value
         uint256 value = isNativePool ? amtIn : 0;
@@ -190,6 +204,8 @@ contract CLSwapRouterHandler is Test {
             }),
             block.timestamp + 100
         );
+
+        _accumulateFee();
     }
 
     function exactSwapOutput(uint128 amtIn, bool isNativePool) public {
@@ -203,8 +219,9 @@ contract CLSwapRouterHandler is Test {
         isNativePool ? nativeTokenMinted += amtIn : token0Minted += amtIn;
 
         // Step 3: swap
+        vm.recordLogs();
+
         PoolKey memory pk = isNativePool ? nativePoolKey : poolKey;
-        vm.prank(alice);
         ISwapRouterBase.PathKey[] memory path = new ISwapRouterBase.PathKey[](1);
         path[0] = ISwapRouterBase.PathKey({
             intermediateCurrency: isNativePool ? CurrencyLibrary.NATIVE : currency0,
@@ -217,6 +234,7 @@ contract CLSwapRouterHandler is Test {
 
         // if native pool, have to ensure call method with value
         uint256 value = isNativePool ? amtIn : 0;
+        vm.prank(alice);
         router.exactOutput{value: value}(
             ICLSwapRouterBase.V4CLExactOutputParams({
                 currencyOut: currency1,
@@ -227,6 +245,8 @@ contract CLSwapRouterHandler is Test {
             }),
             block.timestamp + 60
         );
+
+        _accumulateFee();
     }
 
     function _mint(uint128 amt, bool isNativePool) private {
@@ -239,8 +259,6 @@ contract CLSwapRouterHandler is Test {
         token1Minted += amt;
         token1.mint(alice, amt);
 
-        vm.startPrank(alice);
-
         PoolKey memory pk = isNativePool ? nativePoolKey : poolKey;
         INonfungiblePositionManager.MintParams memory mintParams = INonfungiblePositionManager.MintParams({
             poolKey: pk,
@@ -250,17 +268,41 @@ contract CLSwapRouterHandler is Test {
             amount1Desired: amt,
             amount0Min: 0,
             amount1Min: 0,
-            recipient: address(this),
+            recipient: alice,
             deadline: block.timestamp
         });
 
+        vm.startPrank(alice);
         if (isNativePool) {
             positionManager.mint{value: amt}(mintParams);
         } else {
             positionManager.mint(mintParams);
         }
         vm.stopPrank();
     }
+
+    function _accumulateFee() private {
+        // event Swap(
+        //     PoolId indexed id,
+        //     address indexed sender,
+        //     int128 amount0,
+        //     int128 amount1,
+        //     uint160 sqrtPriceX96,
+        //     uint128 liquidity,
+        //     int24 tick,
+        //     uint24 fee,
+        //     uint256 protocolFee
+        // );
+        Vm.Log[] memory entries = vm.getRecordedLogs();
+        (int128 amount0, int128 amount1,,,,,) =
+            abi.decode(entries[0].data, (int128, int128, uint160, uint128, int24, uint24, uint256));
+
+        if (amount0 < 0) {
+            token1FeeAccrued += uint128(amount1) * 3000 / 1e6;
+        } else {
+            token0FeeAccrued += uint128(amount0) * 3000 / 1e6;
+        }
+    }
 }
 
 contract CLSwapRouterInvariant is Test {
@@ -302,4 +344,32 @@ contract CLSwapRouterInvariant is Test {
         uint256 routerBalance = address(_handler.router()).balance;
         assertEq(nativeTokenInVault + nativeTokenWithAlice + routerBalance, _handler.nativeTokenMinted());
     }
+
+    function invariant_AllSwapFeeGoesToLP() public {
+        INonfungiblePositionManager positionManager = INonfungiblePositionManager(_handler.positionManager());
+
+        uint256 positionTokenAmt = positionManager.balanceOf(_handler.alice());
+
+        uint256 realFee0Accrued = 0;
+        uint256 realFee1Accrued = 0;
+        for (uint256 i = 0; i < positionTokenAmt; i++) {
+            uint256 tokenId = positionManager.tokenOfOwnerByIndex(_handler.alice(), i);
+            vm.prank(_handler.alice());
+            positionManager.approve(address(this), tokenId);
+            (uint256 _realFee0Accrued, uint256 _realFee1Accrued) = positionManager.collect(
+                INonfungiblePositionManager.CollectParams({
+                    tokenId: tokenId,
+                    recipient: _handler.alice(),
+                    amount0Max: type(uint128).max,
+                    amount1Max: type(uint128).max
+                })
+            );
+            realFee0Accrued += _realFee0Accrued;
+            realFee1Accrued += _realFee1Accrued;
+        }
+
+        /// @dev due to the precision loss, fee accrued might not be exactly the same
+        assertLe(_handler.token0FeeAccrued() - realFee0Accrued, 10);
+        assertLe(_handler.token1FeeAccrued() - realFee1Accrued, 10);
+    }
 }