fix: Update SP pending yields if deposit makes it reach threshold

contracts/src/StabilityPool.sol

@@ -270,10 +270,16 @@ contract StabilityPool is LiquityBase, IStabilityPool, IStabilityPoolEvents {
 
         _updateDepositAndSnapshots(msg.sender, newDeposit, newStashedColl);
         boldToken.sendToPool(msg.sender, address(this), _topUp);
-        _updateTotalBoldDeposits(_topUp + keptYieldGain, 0);
+        uint256 totalBoldDepositsCached = _updateTotalBoldDeposits(_topUp + keptYieldGain, 0);
         _decreaseYieldGainsOwed(currentYieldGain);
         _sendBoldtoDepositor(msg.sender, yieldGainToSend);
         _sendCollGainToDepositor(collToSend);
+
+        // If there were pending yields and with the new deposit we are reaching the threshold, let’s move the yield to owed
+        uint256 yieldGainsPendingCached = yieldGainsPending;
+        if (yieldGainsPendingCached > 0 && totalBoldDepositsCached >= DECIMAL_PRECISION) {
+            _updateYieldRewardsSum(yieldGainsPendingCached, totalBoldDepositsCached);
+        }
     }
 
     function _getYieldToKeepOrSend(uint256 _currentYieldGain, bool _doClaim) internal pure returns (uint256, uint256) {
@@ -365,22 +371,27 @@ contract StabilityPool is LiquityBase, IStabilityPool, IStabilityPoolEvents {
 
     function triggerBoldRewards(uint256 _boldYield) external {
         _requireCallerIsActivePool();
+        assert(_boldYield > 0); // TODO: remove before deploying
 
         uint256 totalBoldDepositsCached = totalBoldDeposits; // cached to save an SLOAD
 
-        assert(_boldYield > 0); // TODO: remove before deploying
-
         // When total deposits is very small, B is not updated. In this case, the BOLD issued can not be obtained by later
         // depositors - it is missed out on, and remains in the balance of the SP.
         if (totalBoldDepositsCached < DECIMAL_PRECISION) {
             yieldGainsPending += _boldYield;
             return;
         }
 
-        yieldGainsOwed += yieldGainsPending + _boldYield;
+        _updateYieldRewardsSum(yieldGainsPending + _boldYield, totalBoldDepositsCached);
+    }
+
+    function _updateYieldRewardsSum(uint256 _accumulatedYield, uint256 _totalBoldDeposits) internal {
+        assert(_accumulatedYield > 0); // TODO: remove before deploying
+
+        yieldGainsOwed += _accumulatedYield;
         yieldGainsPending = 0;
 
-        uint256 yieldPerUnitStaked = _computeYieldPerUnitStaked(_boldYield, totalBoldDepositsCached);
+        uint256 yieldPerUnitStaked = _computeYieldPerUnitStaked(_accumulatedYield, _totalBoldDeposits);
 
         uint256 marginalYieldGain = yieldPerUnitStaked * P;
         epochToScaleToB[currentEpoch][currentScale] = epochToScaleToB[currentEpoch][currentScale] + marginalYieldGain;
@@ -544,11 +555,13 @@ contract StabilityPool is LiquityBase, IStabilityPool, IStabilityPoolEvents {
         emit StabilityPoolCollBalanceUpdated(newCollBalance);
     }
 
-    function _updateTotalBoldDeposits(uint256 _depositIncrease, uint256 _depositDecrease) internal {
-        if (_depositIncrease == 0 && _depositDecrease == 0) return;
+    function _updateTotalBoldDeposits(uint256 _depositIncrease, uint256 _depositDecrease) internal returns (uint256) {
+        if (_depositIncrease == 0 && _depositDecrease == 0) return totalBoldDeposits;
         uint256 newTotalBoldDeposits = totalBoldDeposits + _depositIncrease - _depositDecrease;
         totalBoldDeposits = newTotalBoldDeposits;
         emit StabilityPoolBoldBalanceUpdated(newTotalBoldDeposits);
+
+        return newTotalBoldDeposits;
     }
 
     function _decreaseYieldGainsOwed(uint256 _amount) internal {