feat: sweep from loss checker

feat: sweep from loss checker

Author: wavey0x

contracts/LossOnFeeChecker.sol

@@ -1,6 +1,11 @@
 pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
+import {
+    SafeERC20,
+    IERC20
+} from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
+
 interface IVault {
     struct StrategyParams {
         uint performanceFee;
@@ -27,9 +32,11 @@ interface IStrategy {
 /// @notice Designed to prevent Management fees from creating lossy reports on Yearn vaults with API < 0.3.5
 /// @dev Begining with vaults API v0.3.5 management fees are adjust dynamically on report to prevent loss
 contract LossOnFeeChecker {
+    using SafeERC20 for IERC20;
 
     uint constant MAX_BPS = 10_000;
     uint constant SECS_PER_YEAR = 31_557_600;
+    mapping(address=>bool) public approvedSweepers;
 
     /// @notice Check if harvest does not contain a loss after fees
     /// @dev should be called automically report transaction
@@ -83,5 +90,17 @@ contract LossOnFeeChecker {
             return governanceFee + grossLoss;
         }
     }
+
+    function sweep(address _token, uint _amount) external {
+        require(approvedSweepers[msg.sender], "!approved");
+        IERC20(_token).transfer(msg.sender, _amount);
+    }
+
+    function approveSweepers(address _sweeper, bool _approved) external {
+        address ychad = 0xFEB4acf3df3cDEA7399794D0869ef76A6EfAff52;
+        address brain = 0x16388463d60FFE0661Cf7F1f31a7D658aC790ff7;
+        require(msg.sender == ychad || msg.sender == brain);
+        approvedSweepers[_sweeper] = _approved;
+    }
 }
 

contracts/RouterStrategy.sol

@@ -14,6 +14,7 @@ import "@openzeppelin/contracts/math/Math.sol";
 
 interface ILossChecker {
     function checkLoss(uint, uint) external view returns (uint);
+    function sweep(address, uint) external;
 }
 
 interface IVault is IERC20 {
@@ -169,7 +170,11 @@ contract RouterStrategy is BaseStrategy {
             _loss = 0;
         }
 
-        require(lossChecker.checkLoss(_profit, _loss) <= feeLossTolerance, "TooLossy!");
+        uint expectedLoss = lossChecker.checkLoss(_profit, _loss);
+        if (expectedLoss > feeLossTolerance){
+            require(want.balanceOf(address(lossChecker)) > expectedLoss, "LossyWithFees");
+            lossChecker.sweep(address(want), expectedLoss);
+        }
     }
 
     function adjustPosition(uint256 _debtOutstanding)

tests/test_operation_steth.py

@@ -26,15 +26,13 @@ def test_migrate(origin_vault, destination_vault, strategy, gov, loss_checker):
     whale = accounts.at('0x99ac10631F69C753DDb595D074422a0922D9056B', force=True)
     want = Contract(origin_vault.token(),owner=whale)
     # want.transfer(strategy, expected_loss + 1e17)
-    assert False
 
     totalShares = origin_vault.totalSupply()
     tx = strategy.harvest({"from": gov})
     totalSharesAfter = origin_vault.totalSupply()
     assert totalSharesAfter <= totalShares
 
     print(tx.events['Harvested'])
-    assert False
     # origin_vault.updateStrategyDebtRatio(strategy, 10_000, {'from':gov})