refactor: add shares

src/contracts/core/DelegationManager.sol

@@ -636,7 +636,7 @@ contract DelegationManager is
     ) internal {
         // Finalize action by converting scaled shares to tokens for each strategy, or
         // by re-awarding shares in each strategy.
-        for (uint256 i = 0; i < withdrawal.strategies.length; ++i) {
+        for (uint256 i = 0; i < withdrawal.strategies.length;) {
             uint256 sharesToWithdraw;
             if (isLegacyWithdrawal) {
                 // This is a legacy M2 withdrawal. There is no slashing applied to the withdrawn shares.
@@ -666,6 +666,10 @@ contract DelegationManager is
                     token: tokens[i]
                 });
             }
+
+            unchecked {
+                ++i;
+            }
         }
     }
 
@@ -685,7 +689,7 @@ contract DelegationManager is
         // read delegated operator for scaling and adding shares back if needed
         address currentOperator = delegatedTo[msg.sender];
 
-        for (uint256 i = 0; i < withdrawal.strategies.length; ++i) {
+        for (uint256 i = 0; i < withdrawal.strategies.length;) {
             // store existing shares to calculate new staker scaling factor later
             uint256 existingShares;
             uint256 shares;
@@ -704,6 +708,8 @@ contract DelegationManager is
              * Other strategy shares can + will be awarded to the withdrawer.
              */
             if (withdrawal.strategies[i] == beaconChainETHStrategy) {
+                // TODO: REFACTOR EPM AND NEGATIVE SHARES
+
                 address staker = withdrawal.staker;
                 /**
                  * Update shares amount depending upon the returned value.
@@ -723,29 +729,12 @@ contract DelegationManager is
                     });
                 }
             } else {
-                existingShares = strategyManager.addShares(msg.sender, tokens[i], withdrawal.strategies[i], shares);
-                // Similar to `isDelegated` logic
-                if (currentOperator != address(0)) {
-                    _increaseOperatorScaledShares({
-                        operator: currentOperator,
-                        // the 'staker' here is the address receiving new shares
-                        staker: msg.sender,
-                        strategy: withdrawal.strategies[i],
-                        shares: shares,
-                        totalMagnitude: totalMagnitudes[i]
-                    });
-                }
+                strategyManager.addShares(msg.sender, tokens[i], withdrawal.strategies[i], shares);
             }
 
-            // update stakers scaling deposit scaling factor
-            uint256 newStakerScalingFactor = SlashingLib.calculateStakerScalingFactor({
-                staker: withdrawal.staker,
-                currStakerScalingFactor: _getStakerScalingFactor(withdrawal.staker, withdrawal.strategies[i]),
-                totalMagnitude: totalMagnitudes[i],
-                existingShares: existingShares,
-                addedShares: shares
-            });
-            stakerScalingFactors[withdrawal.staker][withdrawal.strategies[i]] = newStakerScalingFactor;
+            unchecked {
+                ++i;
+            }
         }
     }
 

src/contracts/core/StrategyManager.sol

@@ -168,9 +168,8 @@ contract StrategyManager is
         IERC20 token,
         IStrategy strategy,
         uint256 shares
-    ) external onlyDelegationManager returns (uint256 existingShares) {
-        uint256 existingShares = _addShares(staker, token, strategy, shares);
-        return existingShares;
+    ) external onlyDelegationManager {
+        _addShares(staker, token, strategy, shares);
     }
 
     /// @notice Used by the DelegationManager to convert withdrawn shares to tokens and send them to a recipient
@@ -241,12 +240,7 @@ contract StrategyManager is
      * delegated shares are tracked, increases the stored share amount in `stakerStrategyShares[staker][strategy]`, and adds `strategy`
      * to the `staker`'s list of strategies, if it is not in the list already.
      */
-    function _addShares(
-        address staker,
-        IERC20 token,
-        IStrategy strategy,
-        uint256 shares
-    ) internal returns (uint256 existingShares) {
+    function _addShares(address staker, IERC20 token, IStrategy strategy, uint256 shares) internal {
         // sanity checks on inputs
         require(staker != address(0), StakerAddressZero());
         require(shares != 0, SharesAmountZero());
@@ -258,11 +252,18 @@ contract StrategyManager is
         }
 
         // add the returned shares to their existing shares for this strategy
-        existingShares = stakerStrategyShares[staker][strategy];
+        uint256 existingShares = stakerStrategyShares[staker][strategy];
         stakerStrategyShares[staker][strategy] += shares;
 
+        // Increase shares delegated to operator, if needed
+        delegation.increaseDelegatedShares({
+            staker: staker,
+            strategy: strategy,
+            existingShares: existingShares,
+            addedShares: shares
+        });
+
         emit Deposit(staker, token, strategy, shares);
-        return existingShares;
     }
 
     /**
@@ -287,15 +288,7 @@ contract StrategyManager is
         uint256 shares = strategy.deposit(token, amount);
 
         // add the returned shares to the staker's existing shares for this strategy
-        uint256 existingShares = _addShares(staker, token, strategy, shares);
-
-        // Increase shares delegated to operator, if needed
-        delegation.increaseDelegatedShares({
-            staker: staker,
-            strategy: strategy,
-            existingShares: existingShares,
-            addedShares: shares
-        });
+        _addShares(staker, token, strategy, shares);
 
         return shares;
     }

src/contracts/interfaces/IStrategyManager.sol

@@ -99,12 +99,7 @@ interface IStrategyManager {
     function removeShares(address staker, IStrategy strategy, uint256 shares) external;
 
     /// @notice Used by the DelegationManager to award a Staker some shares that have passed through the withdrawal queue
-    function addShares(
-        address staker,
-        IERC20 token,
-        IStrategy strategy,
-        uint256 shares
-    ) external returns (uint256 existingShares);
+    function addShares(address staker, IERC20 token, IStrategy strategy, uint256 shares) external;
 
     /// @notice Used by the DelegationManager to convert withdrawn descaled shares to tokens and send them to a recipient
     function withdrawSharesAsTokens(address recipient, IStrategy strategy, uint256 shares, IERC20 token) external;

src/test/mocks/StrategyManagerMock.sol

@@ -110,7 +110,7 @@ contract StrategyManagerMock is
 
     function removeShares(address staker, IStrategy strategy, uint256 shares) external {}
 
-    function addShares(address staker, IERC20 token, IStrategy strategy, uint256 shares) external returns (uint256 existingShares) {}
+    function addShares(address staker, IERC20 token, IStrategy strategy, uint256 shares) external {}
 
     function withdrawSharesAsTokens(address recipient, IStrategy strategy, uint256 shares, IERC20 token) external {}