Merge pull request #54 from Gearbox-protocol/fix--zapper-weth-fix

feat(zappers): `tokenOut` + approval fix

contracts/interfaces/zappers/IZapper.sol

@@ -6,6 +6,8 @@ pragma solidity ^0.8.17;
 interface IZapper {
     function pool() external view returns (address);
 
+    function tokenOut() external view returns (address);
+
     function unwrappedToken() external view returns (address);
 
     function wrappedToken() external view returns (address);

contracts/test/live/zappers/ZapperPlay.sol

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: UNLICENSED
+// Gearbox Protocol. Generalized leverage for DeFi protocols
+// (c) Gearbox Foundation, 2023.
+pragma solidity ^0.8.17;
+
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+import {IERC20Metadata} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
+import {WETHZapper} from "../../../zappers/WETHZapper.sol";
+import {NetworkDetector} from "@gearbox-protocol/sdk-gov/contracts/NetworkDetector.sol";
+import "@gearbox-protocol/core-v3/contracts/test/lib/constants.sol";
+
+import {Test} from "forge-std/Test.sol";
+import "forge-std/console.sol";
+
+address constant ap = 0x0Bf1626d4925F8A872801968be11c052862AC2D3;
+
+contract ZapperTest is Test {
+    uint256 chainId;
+    WETHZapper wethZapper;
+
+    address weth = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
+
+    constructor() {
+        NetworkDetector nd = new NetworkDetector();
+        chainId = nd.chainId();
+    }
+
+    modifier liveTestOnly() {
+        if (chainId == 1) {
+            _;
+        }
+    }
+
+    function setUp() public liveTestOnly {
+        wethZapper = new WETHZapper(0x9357C9b42b9a555fCcF94cA5C702d72782865B71);
+    }
+
+    function test_weth_zapper() public liveTestOnly {
+        console.log("Allowance", IERC20(weth).allowance(address(wethZapper), wethZapper.pool()));
+        vm.prank(USER);
+        wethZapper.deposit{value: 10 ether}(USER);
+    }
+}

contracts/zappers/WATokenZapper.sol

@@ -20,7 +20,7 @@ contract WATokenZapper is WERC20ZapperBase {
     /// @param pool_ Pool to connect this zapper to
     constructor(address pool_) WERC20ZapperBase(pool_) {
         _aToken = WrappedAToken(wrappedToken).aToken();
-        _resetWrapperAllowance();
+        super._resetWrapperAllowance();
     }
 
     /// @notice aToken address

contracts/zappers/WERC20ZapperBase.sol

@@ -13,8 +13,8 @@ import {ZapperBase} from "./ZapperBase.sol";
 /// @notice Base contract for zappers allowing users to deposit/withdraw an ERC20 token
 ///         to/from a Gearbox pool with its wrapper as underlying in a single operation
 /// @dev Default implementation assumes that unwrapped token has no transfer fees
-/// @dev Derived zappers must call `_resetWrapperAllowance` in their constructor after
-///      initializing `unwrappedToken()`
+/// @dev Derived zappers must call `super._resetWrapperAllowance()` in their constructor
+///      after initializing `unwrappedToken()`
 abstract contract WERC20ZapperBase is ZapperBase, IWERC20Zapper {
     using SafeERC20 for IERC20;
 

contracts/zappers/WstETHZapper.sol

@@ -18,7 +18,7 @@ contract WstETHZapper is WERC20ZapperBase {
     /// @param pool_ Pool to connect this zapper to
     constructor(address pool_) WERC20ZapperBase(pool_) {
         _stETH = IwstETH(wrappedToken).stETH();
-        _resetWrapperAllowance();
+        super._resetWrapperAllowance();
     }
 
     /// @notice stETH address

contracts/zappers/ZapperBase.sol

@@ -18,6 +18,7 @@ abstract contract ZapperBase is IZapper {
 
     /// @notice Pool this zapper is connected to
     address public immutable override pool;
+
     /// @notice Underlying token of the pool
     address public immutable override wrappedToken;
 
@@ -26,7 +27,12 @@ abstract contract ZapperBase is IZapper {
     constructor(address pool_) {
         pool = pool_;
         wrappedToken = IPoolV3(pool_).asset();
-        _resetPoolAllowance();
+        ZapperBase._resetPoolAllowance();
+    }
+
+    /// @notice Token that this zapper produces (might differ from the pool share token)
+    function tokenOut() public view virtual override returns (address) {
+        return pool;
     }
 
     /// @notice Returns number of pool shares one would receive for depositing `amount` of unwrapped token