beforeSwap returns dynamic fee

.forge-snapshots/poolManager bytecode size.snap

@@ -1 +1 @@
-22114
+22121

.forge-snapshots/simple swap with native.snap

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-117426
+117431

.forge-snapshots/simple swap.snap

@@ -1 +1 @@
-132587
+132592

.forge-snapshots/swap CA custom curve + swap noop.snap

@@ -1 +1 @@
-134706
+134711

.forge-snapshots/swap CA fee on unspecified.snap

@@ -1 +1 @@
-183725
+183730

.forge-snapshots/swap against liquidity with native token.snap

@@ -1 +1 @@
-113051
+113056

.forge-snapshots/swap against liquidity.snap

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-124394
+124399

.forge-snapshots/swap burn 6909 for input.snap

@@ -1 +1 @@
-136447
+136452

.forge-snapshots/swap burn native 6909 for input.snap

@@ -1 +1 @@
-125575
+125580

.forge-snapshots/swap mint native output as 6909.snap

@@ -1 +1 @@
-147636
+147641

.forge-snapshots/swap mint output as 6909.snap

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-164441
+164446

.forge-snapshots/swap skips hook call if hook is caller.snap

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-223302
+223312

.forge-snapshots/swap with dynamic fee.snap

@@ -1 +1 @@
-148642
+148647

.forge-snapshots/swap with hooks.snap

@@ -1 +1 @@
-124406
+124411

.forge-snapshots/swap with lp fee and protocol fee.snap

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-180879
+180884

.forge-snapshots/swap with return dynamic fee.snap

@@ -1 +1 @@
-156492
+156577

.forge-snapshots/update dynamic fee in before swap.snap

@@ -1 +1 @@
-159116
+159121

src/libraries/LPFeeLibrary.sol

@@ -49,4 +49,11 @@ library LPFeeLibrary {
     function removeOverrideFlag(uint24 self) internal pure returns (uint24) {
         return self & FEE_MASK;
     }
+
+    /// @notice Removes the override flag and validates the fee (reverts if the fee is too large)
+    function removeOverrideAndValidate(uint24 self) internal pure returns (uint24) {
+        uint24 fee = self.removeOverrideFlag();
+        fee.validate();
+        return fee;
+    }
 }

src/libraries/Pool.sol

@@ -320,13 +320,8 @@ library Pool {
         state.liquidity = cache.liquidityStart;
 
         // if the beforeSwap hook returned a valid fee override, use that as the LP fee, otherwise load from storage
-        uint24 lpFee;
-        if (!params.lpFeeOverride.isOverride()) {
-            lpFee = slot0Start.lpFee;
-        } else {
-            lpFee = params.lpFeeOverride.removeOverrideFlag();
-            if (!lpFee.isValid()) lpFee = slot0Start.lpFee;
-        }
+        uint24 lpFee =
+            params.lpFeeOverride.isOverride() ? params.lpFeeOverride.removeOverrideAndValidate() : slot0Start.lpFee;
 
         swapFee = cache.protocolFee == 0 ? lpFee : uint24(cache.protocolFee).calculateSwapFee(lpFee);
 

test/DynamicReturnFees.t.sol

@@ -60,14 +60,23 @@ contract TestDynamicReturnFees is Test, Deployers, GasSnapshot {
     }
 
     function test_fuzz_dynamicReturnSwapFee(uint24 fee) public {
+        // hook will handle adding the override flag
         dynamicReturnFeesHook.setFee(fee);
 
-        int256 amountSpecified = -10000;
-        BalanceDelta result = swap(key, true, amountSpecified, ZERO_BYTES);
+        uint24 actualFee = fee.removeOverrideFlag();
 
+        int256 amountSpecified = -10000;
+        BalanceDelta result;
+        if (actualFee > LPFeeLibrary.MAX_LP_FEE) {
+            vm.expectRevert(LPFeeLibrary.FeeTooLarge.selector);
+            result = swap(key, true, amountSpecified, ZERO_BYTES);
+            return;
+        } else {
+            result = swap(key, true, amountSpecified, ZERO_BYTES);
+        }
+        // BalanceDelta result = swap(key, true, amountSpecified, ZERO_BYTES);
         assertEq(result.amount0(), amountSpecified);
 
-        uint24 actualFee = fee.removeOverrideFlag();
         if (actualFee > LPFeeLibrary.MAX_LP_FEE) {
             // if the fee is too large, the fee from beforeSwap is not used (and remains at 0 -- the default value)
             assertApproxEqAbs(uint256(int256(result.amount1())), uint256(int256(-result.amount0())), 1 wei);
@@ -150,18 +159,16 @@ contract TestDynamicReturnFees is Test, Deployers, GasSnapshot {
         assertEq(_fetchPoolSwapFee(key), initialFee);
     }
 
-    function test_dynamicReturnSwapFee_notUsedWithTooLargeFee() public {
+    function test_dynamicReturnSwapFee_revertIfFeeTooLarge() public {
         assertEq(_fetchPoolSwapFee(key), 0);
 
+        // hook adds the override flag
         dynamicReturnFeesHook.setFee(1000001);
 
         // a large fee is not used
         int256 amountSpecified = -10000;
-        BalanceDelta result = swap(key, true, amountSpecified, ZERO_BYTES);
-
-        // after swapping ~1:1 on 0% fee, the amount out (amount1) should be equal to amount specified
-        assertEq(result.amount0(), amountSpecified);
-        assertApproxEqAbs(uint256(int256(result.amount1())), uint256(int256(-result.amount0())), 1 wei);
+        vm.expectRevert(LPFeeLibrary.FeeTooLarge.selector);
+        swap(key, true, amountSpecified, ZERO_BYTES);
     }
 
     function _fetchPoolSwapFee(PoolKey memory _key) internal view returns (uint256 swapFee) {

test/libraries/Pool.t.sol

@@ -119,11 +119,15 @@ contract PoolTest is Test {
         );
         Pool.Slot0 memory slot0 = state.slot0;
 
-        uint24 _lpFee = params.lpFeeOverride.isValid() ? params.lpFeeOverride : lpFee;
+        uint24 _lpFee = params.lpFeeOverride.isOverride() ? params.lpFeeOverride.removeOverrideFlag() : lpFee;
         uint24 swapFee = protocolFee == 0 ? _lpFee : uint24(protocolFee).calculateSwapFee(_lpFee);
-        if (params.amountSpecified > 0 && swapFee == MAX_LP_FEE) {
+
+        if (params.amountSpecified >= 0 && swapFee == MAX_LP_FEE) {
             vm.expectRevert(Pool.InvalidFeeForExactOut.selector);
             state.swap(params);
+        } else if (!swapFee.isValid()) {
+            vm.expectRevert(LPFeeLibrary.FeeTooLarge.selector);
+            state.swap(params);
         } else if (params.zeroForOne && params.amountSpecified != 0) {
             if (params.sqrtPriceLimitX96 >= slot0.sqrtPriceX96) {
                 vm.expectRevert(