fix(protocol-contracts): add fees event in OperatorStaking constructor and revert PR #1720 (#1731)

Author: melanciani

protocol-contracts/staking/contracts/OperatorRewarder.sol

@@ -164,15 +164,14 @@ contract OperatorRewarder {
         _protocolStaking = protocolStaking_;
         _operatorStaking = operatorStaking_;
 
-        // Set fee values directly without calling `setFee()` or `setMaxFee()`, which would snapshot
+        // Since `feeBasisPoints()` is not initialized and thus null, calling `_setMaxFee` only sets
+        // the max fee value without calling `_setFee` internally, so there is no need to define a
+        // new `_setInitialMaxFee` as opposed to setting fees
+        _setMaxFee(initialMaxFeeBasisPoints_);
+
+        // Set fee value directly without claiming fees, which would snapshot
         // `_lastClaimTotalAssetsPlusPaidRewards` via `claimFee()` with potentially stale pending rewards.
-        require(initialMaxFeeBasisPoints_ <= 10000, InvalidBasisPoints(initialMaxFeeBasisPoints_));
-        require(
-            initialFeeBasisPoints_ <= initialMaxFeeBasisPoints_,
-            MaxBasisPointsExceeded(initialFeeBasisPoints_, initialMaxFeeBasisPoints_)
-        );
-        _maxFeeBasisPoints = initialMaxFeeBasisPoints_;
-        _feeBasisPoints = initialFeeBasisPoints_;
+        _setInitialFee(initialFeeBasisPoints_);
     }
 
     /**
@@ -200,9 +199,11 @@ contract OperatorRewarder {
      * @notice Claims rewards for a delegator. The caller must be authorized to claim rewards on
      * behalf of the delegator. By default, the caller is authorized to claim rewards on behalf of
      * themselves.
+     * @dev It can only be called once the rewarder has started to avoid allowing anyone to drain
+     * rewards generated by donations sent beforehand.
      * @param receiver The delegator's address that will receive the rewards.
      */
-    function claimRewards(address receiver) public virtual onlyClaimer(receiver) {
+    function claimRewards(address receiver) public virtual whenStarted onlyClaimer(receiver) {
         uint256 earned_ = earned(receiver);
         if (earned_ > 0) {
             _rewardsPaid[receiver] += SafeCast.toInt256(earned_);
@@ -496,6 +497,19 @@ contract OperatorRewarder {
         _feeBasisPoints = basisPoints;
     }
 
+    /**
+     * @notice Sets the initial fee in basis points (1/100th of a percent) without claiming fees.
+     * @param basisPoints Fee in basis points (cannot be greater than the maximum fee).
+     */
+    function _setInitialFee(uint16 basisPoints) internal virtual {
+        // The following statement also makes sure the basis points is not greater than 10000, as
+        // the max fee basis points also follows this constraint.
+        require(basisPoints <= maxFeeBasisPoints(), MaxBasisPointsExceeded(basisPoints, maxFeeBasisPoints()));
+
+        emit FeeUpdated(feeBasisPoints(), basisPoints);
+        _feeBasisPoints = basisPoints;
+    }
+
     /**
      * @notice Returns the total assets plus earned rewards plus paid rewards.
      * @dev This amount is computed as the sum of: