Merge pull request #184 from Gearbox-protocol/upshift-fix

fix: upshift gateway correctly handles lagDuration == 0

Author: lekhovitsky

contracts/helpers/upshift/UpshiftVaultGateway.sol

@@ -22,7 +22,7 @@ contract UpshiftVaultGateway is ReentrancyGuardTrait, IUpshiftVaultGateway {
     using SafeERC20 for IERC20;
 
     bytes32 public constant override contractType = "GATEWAY::UPSHIFT_VAULT";
-    uint256 public constant override version = 3_10;
+    uint256 public constant override version = 3_11;
 
     address public immutable upshiftVault;
 
@@ -54,15 +54,16 @@ contract UpshiftVaultGateway is ReentrancyGuardTrait, IUpshiftVaultGateway {
             revert("UpshiftVaultGateway: user has a pending redeem");
         }
 
-        (uint256 year, uint256 month, uint256 day, uint256 claimableTimestamp) =
-            IUpshiftVault(upshiftVault).getWithdrawalEpoch();
+        (uint256 year, uint256 month, uint256 day,) = IUpshiftVault(upshiftVault).getWithdrawalEpoch();
 
-        uint256 assets = IERC4626(upshiftVault).previewRedeem(shares);
+        (uint256 assets, uint256 claimableTimestamp) = IUpshiftVault(upshiftVault).requestRedeem({
+            shares: shares,
+            receiverAddr: address(this),
+            holderAddr: msg.sender
+        });
 
         pendingRedeems[msg.sender] =
             PendingRedeem({claimableTimestamp: claimableTimestamp, assets: assets, year: year, month: month, day: day});
-
-        IUpshiftVault(upshiftVault).requestRedeem({shares: shares, receiverAddr: address(this), holderAddr: msg.sender});
     }
 
     function claim(uint256 amount) external nonReentrant {

contracts/integrations/upshift/IUpshiftVault.sol

@@ -2,7 +2,9 @@
 pragma solidity ^0.8.10;
 
 interface IUpshiftVault {
-    function requestRedeem(uint256 shares, address receiverAddr, address holderAddr) external;
+    function requestRedeem(uint256 shares, address receiverAddr, address holderAddr)
+        external
+        returns (uint256 assets, uint256 claimableTimestamp);
 
     function claim(uint256 year, uint256 month, uint256 day, address receiverAddr) external;