feat: Add TokenTransfer class to BalancerV2

- This needed to be in BalancerV2 so that the executor can also take care of transfers from the user into the tycho router, to avoid having transfer actions mixed between the router and executors

foundry/src/executors/BalancerV2Executor.sol

@@ -10,14 +10,17 @@ import {
 import {IAsset} from "@balancer-labs/v2-interfaces/contracts/vault/IAsset.sol";
 // slither-disable-next-line solc-version
 import {IVault} from "@balancer-labs/v2-interfaces/contracts/vault/IVault.sol";
+import {TokenTransfer} from "./TokenTransfer.sol";
 
 error BalancerV2Executor__InvalidDataLength();
 
-contract BalancerV2Executor is IExecutor {
+contract BalancerV2Executor is IExecutor, TokenTransfer {
     using SafeERC20 for IERC20;
 
     address private constant VAULT = 0xBA12222222228d8Ba445958a75a0704d566BF2C8;
 
+    constructor(address _permit2) TokenTransfer(_permit2) {}
+
     // slither-disable-next-line locked-ether
     function swap(uint256 givenAmount, bytes calldata data)
         external
@@ -29,9 +32,20 @@ contract BalancerV2Executor is IExecutor {
             IERC20 tokenOut,
             bytes32 poolId,
             address receiver,
-            bool needsApproval
+            bool needsApproval,
+            TransferType transferType
         ) = _decodeData(data);
 
+        _transfer(
+            address(tokenIn),
+            msg.sender,
+            // Receiver can never be the pool, since the pool expects funds in the router contract
+            // Thus, this call will only ever be used to transfer funds from the user into the router.
+            address(this),
+            givenAmount,
+            transferType
+        );
+
         if (needsApproval) {
             // slither-disable-next-line unused-return
             tokenIn.approve(VAULT, type(uint256).max);
@@ -67,10 +81,11 @@ contract BalancerV2Executor is IExecutor {
             IERC20 tokenOut,
             bytes32 poolId,
             address receiver,
-            bool needsApproval
+            bool needsApproval,
+            TransferType transferType
         )
     {
-        if (data.length != 93) {
+        if (data.length != 94) {
             revert BalancerV2Executor__InvalidDataLength();
         }
 
@@ -79,5 +94,6 @@ contract BalancerV2Executor is IExecutor {
         poolId = bytes32(data[40:72]);
         receiver = address(bytes20(data[72:92]));
         needsApproval = uint8(data[92]) > 0;
+        transferType = TransferType(uint8(data[93]));
     }
 }

foundry/src/executors/CurveExecutor.sol

@@ -64,7 +64,15 @@ contract CurveExecutor is IExecutor, TokenTransfer {
             TransferType transferType
         ) = _decodeData(data);
 
-        _transfer(tokenIn, msg.sender, pool, amountIn, transferType);
+        _transfer(
+            tokenIn,
+            msg.sender,
+            // Receiver can never be the pool, since the pool expects funds in the router contract
+            // Thus, this call will only ever be used to transfer funds from the user into the router.
+            address(this),
+            amountIn,
+            transferType
+        );
 
         if (tokenApprovalNeeded && tokenIn != nativeToken) {
             // slither-disable-next-line unused-return

foundry/src/executors/UniswapV4Executor.sol

@@ -53,7 +53,9 @@ contract UniswapV4Executor is IExecutor, V4Router, ICallback, TokenTransfer {
         _transfer(
             tokenIn,
             msg.sender,
-            address(this), // irrelevant attribute
+            // Receiver can never be the pool, since the pool expects funds in the router contract
+            // Thus, this call will only ever be used to transfer funds from the user into the router.
+            address(this),
             amountIn,
             transferType
         );

foundry/test/TychoRouterTestSetup.sol

@@ -106,7 +106,7 @@ contract TychoRouterTestSetup is Constants, Permit2TestHelper {
         pancakev3Executor = new UniswapV3Executor(
             factoryPancakeV3, initCodePancakeV3, PERMIT2_ADDRESS
         );
-        balancerv2Executor = new BalancerV2Executor();
+        balancerv2Executor = new BalancerV2Executor(PERMIT2_ADDRESS);
         ekuboExecutor = new EkuboExecutor(ekuboCore);
         curveExecutor = new CurveExecutor(ETH_ADDR_FOR_CURVE, PERMIT2_ADDRESS);
 

foundry/test/executors/BalancerV2Executor.t.sol

@@ -6,6 +6,8 @@ import {Test} from "../../lib/forge-std/src/Test.sol";
 import {Constants} from "../Constants.sol";
 
 contract BalancerV2ExecutorExposed is BalancerV2Executor {
+    constructor(address _permit2) BalancerV2Executor(_permit2) {}
+
     function decodeParams(bytes calldata data)
         external
         pure
@@ -14,18 +16,15 @@ contract BalancerV2ExecutorExposed is BalancerV2Executor {
             IERC20 tokenOut,
             bytes32 poolId,
             address receiver,
-            bool needsApproval
+            bool needsApproval,
+            TransferType transferType
         )
     {
         return _decodeData(data);
     }
 }
 
-contract BalancerV2ExecutorTest is
+contract BalancerV2ExecutorTest is Test, Constants {
-    BalancerV2ExecutorExposed,
-    Test,
-    Constants
-{
     using SafeERC20 for IERC20;
 
     BalancerV2ExecutorExposed balancerV2Exposed;
@@ -37,12 +36,17 @@ contract BalancerV2ExecutorTest is
     function setUp() public {
         uint256 forkBlock = 17323404;
         vm.createSelectFork(vm.rpcUrl("mainnet"), forkBlock);
-        balancerV2Exposed = new BalancerV2ExecutorExposed();
+        balancerV2Exposed = new BalancerV2ExecutorExposed(PERMIT2_ADDRESS);
     }
 
     function testDecodeParams() public view {
         bytes memory params = abi.encodePacked(
-            WETH_ADDR, BAL_ADDR, WETH_BAL_POOL_ID, address(2), true
+            WETH_ADDR,
+            BAL_ADDR,
+            WETH_BAL_POOL_ID,
+            address(2),
+            true,
+            TokenTransfer.TransferType.NONE
         );
 
         (
@@ -50,7 +54,8 @@ contract BalancerV2ExecutorTest is
             IERC20 tokenOut,
             bytes32 poolId,
             address receiver,
-            bool needsApproval
+            bool needsApproval,
+            TokenTransfer.TransferType transferType
         ) = balancerV2Exposed.decodeParams(params);
 
         assertEq(address(tokenIn), WETH_ADDR);
@@ -58,6 +63,7 @@ contract BalancerV2ExecutorTest is
         assertEq(poolId, WETH_BAL_POOL_ID);
         assertEq(receiver, address(2));
         assertEq(needsApproval, true);
+        assertEq(uint8(transferType), uint8(TokenTransfer.TransferType.NONE));
     }
 
     function testDecodeParamsInvalidDataLength() public {
@@ -70,8 +76,14 @@ contract BalancerV2ExecutorTest is
 
     function testSwap() public {
         uint256 amountIn = 10 ** 18;
-        bytes memory protocolData =
+        bytes memory protocolData = abi.encodePacked(
-            abi.encodePacked(WETH_ADDR, BAL_ADDR, WETH_BAL_POOL_ID, BOB, true);
+            WETH_ADDR,
+            BAL_ADDR,
+            WETH_BAL_POOL_ID,
+            BOB,
+            true,
+            TokenTransfer.TransferType.NONE
+        );
 
         deal(WETH_ADDR, address(balancerV2Exposed), amountIn);
         uint256 balanceBefore = BAL.balanceOf(BOB);
@@ -86,14 +98,15 @@ contract BalancerV2ExecutorTest is
     function testDecodeIntegration() public view {
         // Generated by the SwapEncoder - test_encode_balancer_v2
         bytes memory protocolData =
-            hex"c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2ba100000625a3754423978a60c9317c58a424e3d5c6ee304399dbdb9c8ef030ab642b10820db8f560002000000000000000000141d96f2f6bef1202e4ce1ff6dad0c2cb002861d3e01";
+            hex"c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2ba100000625a3754423978a60c9317c58a424e3d5c6ee304399dbdb9c8ef030ab642b10820db8f560002000000000000000000141d96f2f6bef1202e4ce1ff6dad0c2cb002861d3e0105";
 
         (
             IERC20 tokenIn,
             IERC20 tokenOut,
             bytes32 poolId,
             address receiver,
-            bool needsApproval
+            bool needsApproval,
+            TokenTransfer.TransferType transferType
         ) = balancerV2Exposed.decodeParams(protocolData);
 
         assertEq(address(tokenIn), WETH_ADDR);
@@ -101,12 +114,13 @@ contract BalancerV2ExecutorTest is
         assertEq(poolId, WETH_BAL_POOL_ID);
         assertEq(receiver, BOB);
         assertEq(needsApproval, true);
+        assertEq(uint8(transferType), uint8(TokenTransfer.TransferType.NONE));
     }
 
     function testSwapIntegration() public {
         // Generated by the SwapEncoder - test_encode_balancer_v2
         bytes memory protocolData =
-            hex"c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2ba100000625a3754423978a60c9317c58a424e3d5c6ee304399dbdb9c8ef030ab642b10820db8f560002000000000000000000141d96f2f6bef1202e4ce1ff6dad0c2cb002861d3e01";
+            hex"c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2ba100000625a3754423978a60c9317c58a424e3d5c6ee304399dbdb9c8ef030ab642b10820db8f560002000000000000000000141d96f2f6bef1202e4ce1ff6dad0c2cb002861d3e0105";
 
         uint256 amountIn = 10 ** 18;
         deal(WETH_ADDR, address(balancerV2Exposed), amountIn);

src/encoding/evm/swap_encoder/swap_encoders.rs

@@ -281,6 +281,7 @@ impl SwapEncoder for BalancerV2SwapEncoder {
             component_id,
             bytes_to_address(&encoding_context.receiver)?,
             approval_needed,
+            (encoding_context.transfer_type as u8).to_be_bytes(),
         );
         Ok(args.abi_encode_packed())
     }
@@ -703,7 +704,7 @@ mod tests {
             router_address: Some(Bytes::zero(20)),
             group_token_in: token_in.clone(),
             group_token_out: token_out.clone(),
-            transfer_type: TransferType::Transfer,
+            transfer_type: TransferType::None,
         };
         let encoder = BalancerV2SwapEncoder::new(
             String::from("0x543778987b293C7E8Cf0722BB2e935ba6f4068D4"),
@@ -731,7 +732,9 @@ mod tests {
                 // receiver
                 "1d96f2f6bef1202e4ce1ff6dad0c2cb002861d3e",
                 // approval needed
-                "01"
+                "01",
+                // transfer type
+                "05"
             ))
         );
     }