feat: hardcode callback and swap selection in dispatcher

foundry/src/Dispatcher.sol

@@ -55,7 +55,6 @@ contract Dispatcher {
     // slither-disable-next-line delegatecall-loop
     function _callExecutor(
         address executor,
-        bytes4 selector,
         uint256 amount,
         bytes calldata data
     ) internal returns (uint256 calculatedAmount) {
@@ -63,10 +62,9 @@ contract Dispatcher {
             revert Dispatcher__UnapprovedExecutor();
         }
 
-        selector = selector == bytes4(0) ? IExecutor.swap.selector : selector;
         // slither-disable-next-line controlled-delegatecall,low-level-calls
         (bool success, bytes memory result) = executor.delegatecall(
-            abi.encodeWithSelector(selector, amount, data)
+            abi.encodeWithSelector(IExecutor.swap.selector, amount, data)
         );
 
         if (!success) {
@@ -83,18 +81,16 @@ contract Dispatcher {
     }
 
     function _handleCallback(bytes calldata data) internal {
-        bytes4 selector = bytes4(data[data.length - 4:]);
         address executor = address(uint160(bytes20(data[data.length - 24:])));
 
         if (!executors[executor]) {
             revert Dispatcher__UnapprovedExecutor();
         }
 
-        selector =
-            selector == bytes4(0) ? ICallback.handleCallback.selector : selector;
         // slither-disable-next-line controlled-delegatecall,low-level-calls
-        (bool success, bytes memory result) =
+        (bool success, bytes memory result) = executor.delegatecall(
-            executor.delegatecall(abi.encodeWithSelector(selector, data));
+            abi.encodeWithSelector(ICallback.handleCallback.selector, data)
+        );
 
         if (!success) {
             revert(

foundry/src/TychoRouter.sol

@@ -286,10 +286,7 @@ contract TychoRouter is AccessControl, Dispatcher, Pausable, ReentrancyGuard {
                 : remainingAmounts[tokenInIndex];
 
             currentAmountOut = _callExecutor(
-                swapData.executor(),
+                swapData.executor(), currentAmountIn, swapData.protocolData()
-                swapData.executorSelector(),
-                currentAmountIn,
-                swapData.protocolData()
             );
             amounts[tokenOutIndex] += currentAmountOut;
             remainingAmounts[tokenOutIndex] += currentAmountOut;

foundry/src/executors/UniswapV4Executor.sol

@@ -16,10 +16,11 @@ import {V4Router} from "@uniswap/v4-periphery/src/V4Router.sol";
 import {Actions} from "@uniswap/v4-periphery/src/libraries/Actions.sol";
 import {IV4Router} from "@uniswap/v4-periphery/src/interfaces/IV4Router.sol";
 import {PathKey} from "@uniswap/v4-periphery/src/libraries/PathKey.sol";
+import {ICallback} from "@interfaces/ICallback.sol";
 
 error UniswapV4Executor__InvalidDataLength();
 
-contract UniswapV4Executor is IExecutor, V4Router {
+contract UniswapV4Executor is IExecutor, V4Router, ICallback {
     using SafeERC20 for IERC20;
     using CurrencyLibrary for Currency;
 
@@ -176,6 +177,16 @@ contract UniswapV4Executor is IExecutor, V4Router {
         }
     }
 
+    function handleCallback(bytes calldata data)
+        external
+        returns (bytes memory)
+    {
+        verifyCallback(data);
+        return _unlockCallback(data);
+    }
+
+    function verifyCallback(bytes calldata) public view onlyPoolManager {}
+
     function _pay(Currency token, address, uint256 amount) internal override {
         IERC20(Currency.unwrap(token)).safeTransfer(
             address(poolManager), amount

foundry/test/ExecutionDispatcher.t.sol

@@ -7,11 +7,10 @@ import "./TychoRouterTestSetup.sol";
 contract DispatcherExposed is Dispatcher {
     function exposedCallExecutor(
         address executor,
-        bytes4 selector,
         uint256 amount,
         bytes calldata data
     ) external returns (uint256 calculatedAmount) {
-        return _callExecutor(executor, selector, amount, data);
+        return _callExecutor(executor, amount, data);
     }
 
     function exposedSetExecutor(address target) external {
@@ -83,10 +82,7 @@ contract DispatcherTest is Constants {
             hex"5615dEB798BB3E4dFa0139dFa1b3D433Cc23b72fc8c39af7983bf329086de522229a7be5fc4e41cc51c72848c68a965f66fa7a88855f9f7784502a7f2606beffe61000613d6a25b5bfef4cd7652aa94777d4a46b39f2e206411280a12c9344b769ff1066c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2a0b86991c6218b36c1d19d4a2e9eb0ce3606eb48000000000000000000000000000000000000000000000000d02ab486cedc0000000000000000000000000000000000000000000000000000000000082ec8ad1b0000000000000000000000000000000000000000000000000000000066d7b65800000000000000000000000000000000000000000000000000000191ba9f843c125000064000640000d52de09955f0ffffffffffffff00225c389e595fe9000001fcc910754b349f821e4bb5d8444822a63920be943aba6f1b31ee14ef0fc6840b6d28d604e04a78834b668dba24a6c082ffb901e4fffa9600649e8d991af593c81c";
         uint256 givenAmount = 15 ether;
         uint256 amount = dispatcherExposed.exposedCallExecutor(
-            0xe592557AB9F4A75D992283fD6066312FF013ba3d,
+            0xe592557AB9F4A75D992283fD6066312FF013ba3d, givenAmount, data
-            IExecutor.swap.selector,
-            givenAmount,
-            data
         );
         assert(amount == 35144641819);
     }
@@ -110,10 +106,7 @@ contract DispatcherTest is Constants {
             hex"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";
         uint256 givenAmount = 15 ether;
         uint256 amount = dispatcherExposed.exposedCallExecutor(
-            0xe592557AB9F4A75D992283fD6066312FF013ba3d,
+            0xe592557AB9F4A75D992283fD6066312FF013ba3d, givenAmount, data
-            bytes4(0),
-            givenAmount,
-            data
         );
         assert(amount == 35144641819);
     }
@@ -127,10 +120,7 @@ contract DispatcherTest is Constants {
             hex"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";
         vm.expectRevert();
         dispatcherExposed.exposedCallExecutor(
-            0xe592557AB9F4A75D992283fD6066312FF013ba3d,
+            0xe592557AB9F4A75D992283fD6066312FF013ba3d, 0, data
-            IExecutor.swap.selector,
-            0,
-            data
         );
     }
 
@@ -138,7 +128,7 @@ contract DispatcherTest is Constants {
         bytes memory data = hex"aabbccdd1111111111111111";
         vm.expectRevert();
         dispatcherExposed.exposedCallExecutor(
-            0x5d622C9053b8FFB1B3465495C8a42E603632bA70, bytes4(0), 0, data
+            0x5d622C9053b8FFB1B3465495C8a42E603632bA70, 0, data
         );
     }
 }