fix: debt withdraw

contracts/VaultV3.vy

@@ -41,7 +41,6 @@ interface IStrategy:
     def balanceOf(owner: address) -> uint256: view
     def maxDeposit(receiver: address) -> uint256: view
     def maxWithdraw(owner: address) -> uint256: view
-    def withdraw(amount: uint256, receiver: address, owner: address) -> uint256: nonpayable
     def redeem(shares: uint256, receiver: address, owner: address) -> uint256: nonpayable
     def deposit(assets: uint256, receiver: address) -> uint256: nonpayable
     def totalAssets() -> (uint256): view
@@ -640,6 +639,18 @@ def _assess_share_of_unrealised_losses(strategy: address, assets_needed: uint256
 
     return losses_user_share
 
+@internal
+def _withdraw_from_strategy(strategy: address, assets_to_withdraw: uint256):
+    # WITHDRAW FROM STRATEGY
+    # Need to get shares since we use redeem to be able to take on losses.
+    shares_to_withdraw: uint256 = min(
+        # Use previewWithdraw since it should round up.
+        IStrategy(strategy).previewWithdraw(assets_to_withdraw), 
+        # And check against our actual balance.
+        IStrategy(strategy).balanceOf(self)
+    )
+    IStrategy(strategy).redeem(shares_to_withdraw, self, self)
+
 @internal
 def _redeem(
     sender: address, 
@@ -943,7 +954,7 @@ def _update_debt(strategy: address, target_debt: uint256) -> uint256:
 
         # Always check the actual amount withdrawn.
         pre_balance: uint256 = ASSET.balanceOf(self)
-        IStrategy(strategy).withdraw(assets_to_withdraw, self, self)
+        self._withdraw_from_strategy(strategy, assets_to_withdraw)
         post_balance: uint256 = ASSET.balanceOf(self)
 
         # making sure we are changing according to the real result no matter what. 

contracts/test/mocks/ERC4626/FaultyStrategy.sol

@@ -58,4 +58,22 @@ contract ERC4626FaultyStrategy is ERC4626BaseStrategyMock {
 
         return shares;
     }
+
+    function redeem(
+        uint256 _shares,
+        address _receiver,
+        address _owner
+    ) public override returns (uint256) {
+        require(
+            _shares <= maxRedeem(_owner),
+            "ERC4626: withdraw more than max"
+        );
+
+        // this will simulate withdrawing less than the vault wanted to
+        uint256 toRedeem = _shares / 2;
+        uint256 assets = previewRedeem(toRedeem);
+        _withdraw(_msgSender(), _receiver, _owner, toRedeem, assets);
+
+        return assets;
+    }
 }

contracts/test/mocks/ERC4626/LockedStrategy.sol

@@ -49,6 +49,16 @@ contract ERC4626LockedStrategy is ERC4626BaseStrategyMock {
         }
     }
 
+    function maxRedeem(address) public view override returns (uint256) {
+        uint256 balance = IERC20(asset()).balanceOf(address(this));
+        if (block.timestamp < lockedUntil) {
+            return convertToShares(balance - lockedBalance);
+        } else {
+            // no locked assets, withdraw all
+            return convertToShares(balance);
+        }
+    }
+
     function migrate(address _newStrategy) external override {
         require(lockedBalance == 0, "strat not liquid");
         IERC20(asset()).safeTransfer(