fix: Add method to exit collateral position after disengaging

contracts/adapters/MorphoLeverageStrategyExtension.sol

@@ -189,6 +189,7 @@ contract MorphoLeverageStrategyExtension is BaseExtension {
     event ExchangeRemoved(
         string _exchangeName
     );
+    event CollateralWithdrawn();
 
     /* ============ Modifiers ============ */
 
@@ -457,6 +458,16 @@ contract MorphoLeverageStrategyExtension is BaseExtension {
         );
     }
 
+    /**
+     * OPERATOR ONLY: Withdraw all collateral from morpho
+     * 
+     * Note: Can only be executed after fully deleveraging / disengaging the strategy. Will revert otherwise.
+     */
+    function exitCollateralPosition() external onlyOperator {
+        _exitCollateralPosition();
+        emit CollateralWithdrawn();
+    }
+
     /**
      * OPERATOR ONLY: Set methodology settings and check new settings are valid. Note: Need to pass in existing parameters if only changing a few settings. Must not be
      * in a rebalance.
@@ -770,6 +781,17 @@ contract MorphoLeverageStrategyExtension is BaseExtension {
         invokeManager(address(strategy.leverageModule), enterPositionCallData);
     }
 
+    function _exitCollateralPosition()
+        internal
+    {
+        bytes memory exitPositionCallData = abi.encodeWithSignature(
+            "exitCollateralPosition(address)",
+            address(strategy.setToken)
+        );
+
+        invokeManager(address(strategy.leverageModule), exitPositionCallData);
+    }
+
     /**
      * Calculate notional rebalance quantity, whether to chunk rebalance based on max trade size and max borrow and invoke lever on MorphoLeverageModule
      *

test/integration/ethereum/morphoLeverageStrategyExtension.spec.ts

@@ -270,7 +270,7 @@ if (process.env.INTEGRATIONTEST) {
       const [, borrowShares, collateral] = await morpho.position(marketId, setToken.address);
       const collateralTokenBalance = await wsteth.balanceOf(setToken.address);
       const collateralTotalBalance = collateralTokenBalance.add(collateral);
-      const [, , totalBorrowAssets, totalBorrowShares, , ] = await morpho.market(marketId);
+      const [, , totalBorrowAssets, totalBorrowShares, ,] = await morpho.market(marketId);
       const borrowAssets = sharesToAssetsUp(borrowShares, totalBorrowAssets, totalBorrowShares);
       return { collateralTotalBalance, borrowAssets };
     }
@@ -3606,6 +3606,22 @@ if (process.env.INTEGRATIONTEST) {
             expect(BigNumber.from(newSecondPosition.unit)).to.gt(ZERO);
             expect(newSecondPosition.module).to.eq(ADDRESS_ZERO);
           });
+
+          it("can run exitCollateralPosition afterwards", async () => {
+            await subject();
+
+            const [, , collateralBefore] = await morpho.position(marketId, setToken.address);
+            await leverageStrategyExtension.exitCollateralPosition();
+            const [, , collateralAfter] = await morpho.position(marketId, setToken.address);
+            expect(await wsteth.balanceOf(setToken.address)).to.eq(collateralBefore);
+            expect(collateralAfter).to.eq(ZERO);
+          });
+
+          it("can't run exitCollateralPosition without disengaging", async () => {
+            await expect(leverageStrategyExtension.exitCollateralPosition()).to.be.revertedWith(
+              "Borrow balance must be 0",
+            );
+          });
         },
       );
     });