Fix: tend() can fail if Hyperdrive vault has deposit caps #18 (#51)

* fix: make _openLong use try-catch to prevent tend() from reverting when hitting deposit caps

* Bug fix: call external IHyperdrive directly instead of the wrapper in HyperdriveExecution lib which is an internal call and blocks try/catch

* Manually add the event emission

* Update test cases according to the new try/catch code

Author: Sean329

contracts/EverlongStrategy.sol

@@ -8,9 +8,10 @@ import { SafeERC20 } from "openzeppelin/token/ERC20/utils/SafeERC20.sol";
 import { BaseStrategy, ERC20 } from "tokenized-strategy/BaseStrategy.sol";
 import { IEverlongStrategy } from "./interfaces/IEverlongStrategy.sol";
 import { IERC20Wrappable } from "./interfaces/IERC20Wrappable.sol";
-import { EVERLONG_STRATEGY_KIND, EVERLONG_VERSION, MAX_BPS, ONE } from "./libraries/Constants.sol";
+import { EVERLONG_STRATEGY_KIND, EVERLONG_VERSION, ONE } from "./libraries/Constants.sol";
 import { EverlongPortfolioLibrary } from "./libraries/EverlongPortfolio.sol";
 import { HyperdriveExecutionLibrary } from "./libraries/HyperdriveExecution.sol";
+import { IEverlongEvents } from "./interfaces/IEverlongEvents.sol";
 
 //           ,---..-.   .-.,---.  ,---.   ,-.    .---.  .-. .-.  ,--,
 //           | .-' \ \ / / | .-'  | .-.\  | |   / .-. ) |  \| |.' .'
@@ -344,8 +345,11 @@ contract EverlongStrategy is BaseStrategy {
                 tendConfig.extraData
             );
 
-            // Account for the new position in the portfolio.
-            _portfolio.handleOpenPosition(maturityTime, bondAmount);
+            // Only update the portfolio if _openLong was successful (indicated by non-zero bondAmount)
+            if (bondAmount > 0) {
+                // Account for the new position in the portfolio.
+                _portfolio.handleOpenPosition(maturityTime, bondAmount);
+            }
         }
     }
 
@@ -708,14 +712,35 @@ contract EverlongStrategy is BaseStrategy {
             ERC20(asset).forceApprove(address(hyperdrive), _toSpend + 1);
         }
 
-        // Open the long. Return the maturity time and amount of bonds received.
-        (maturityTime, bondAmount) = IHyperdrive(hyperdrive).openLong(
-            asBase,
-            _toSpend,
-            _minOutput,
-            _minVaultSharePrice,
-            _extraData
-        );
+        // Open the long using a try-catch to handle potential failures
+        // (e.g., deposit caps) gracefully.
+        try 
+            IHyperdrive(hyperdrive).openLong(
+                _toSpend,
+                _minOutput,
+                _minVaultSharePrice,
+                IHyperdrive.Options({
+                    destination: address(this),
+                    asBase: asBase,
+                    extraData: _extraData
+                })
+            ) 
+        returns (uint256 _maturityTime, uint256 _bondAmount) {
+            maturityTime = _maturityTime;
+            bondAmount = _bondAmount;
+            
+            // Emit the position opened event as the library function would
+            emit IEverlongEvents.PositionOpened(
+                maturityTime.toUint128(),
+                bondAmount.toUint128()
+            );
+        } catch {
+            // If the openLong fails (e.g., due to deposit caps), return zeros
+            // to indicate no position was opened. The calling function (_tend)
+            // will not update the portfolio in this case.
+            maturityTime = 0;
+            bondAmount = 0;
+        }
     }
 
     /// @dev Preview the amount of assets received from closing the specified

test/everlong/units/Tend.t.sol

@@ -227,8 +227,11 @@ contract TestTend is EverlongTest {
         // Set minOutput to a very high value.
         uint256 minOutput = type(uint256).max;
 
-        // Ensure `tend()` reverts.
-        vm.expectRevert();
+        // Record the initial position count and portfolio state
+        uint256 initialPositionCount = IEverlongStrategy(address(strategy)).positionCount();
+        uint256 initialTotalBonds = IEverlongStrategy(address(strategy)).totalBonds();
+
+        // Call tend() with extreme minOutput - should not revert with try/catch in place
         keeperContract.tend(
             address(strategy),
             IEverlongStrategy.TendConfig({
@@ -239,6 +242,18 @@ contract TestTend is EverlongTest {
             })
         );
 
+        // Verify that no new position was opened (portfolio was not updated)
+        assertEq(
+            IEverlongStrategy(address(strategy)).positionCount(),
+            initialPositionCount,
+            "Position count should not change with impossible minOutput"
+        );
+        assertEq(
+            IEverlongStrategy(address(strategy)).totalBonds(),
+            initialTotalBonds,
+            "Total bonds should not change with impossible minOutput"
+        );
+
         // Stop the prank.
         vm.stopPrank();
     }
@@ -257,8 +272,11 @@ contract TestTend is EverlongTest {
         // Set minVaultSharePrice to a very high value.
         uint256 minVaultSharePrice = type(uint256).max;
 
-        // Ensure `tend()` reverts.
-        vm.expectRevert();
+        // Record the initial position count and portfolio state
+        uint256 initialPositionCount = IEverlongStrategy(address(strategy)).positionCount();
+        uint256 initialTotalBonds = IEverlongStrategy(address(strategy)).totalBonds();
+
+        // Call tend() with extreme minVaultSharePrice - should not revert with try/catch in place
         keeperContract.tend(
             address(strategy),
             IEverlongStrategy.TendConfig({
@@ -269,6 +287,18 @@ contract TestTend is EverlongTest {
             })
         );
 
+        // Verify that no new position was opened (portfolio was not updated)
+        assertEq(
+            IEverlongStrategy(address(strategy)).positionCount(),
+            initialPositionCount,
+            "Position count should not change with impossible minVaultSharePrice"
+        );
+        assertEq(
+            IEverlongStrategy(address(strategy)).totalBonds(),
+            initialTotalBonds,
+            "Total bonds should not change with impossible minVaultSharePrice"
+        );
+
         // Stop the prank.
         vm.stopPrank();
     }