Merge remote-tracking branch 'origin/feat/3.0.1' into feat/723-optimi…

…zation

contracts/interfaces/IACLManager.sol

@@ -123,7 +123,7 @@ interface IACLManager {
   function addFlashBorrower(address borrower) external;
 
   /**
-   * @notice Removes an admin as FlashBorrower
+   * @notice Removes an address as FlashBorrower
    * @param borrower The address of the FlashBorrower to remove
    */
   function removeFlashBorrower(address borrower) external;

contracts/interfaces/IPool.sol

@@ -211,7 +211,7 @@ interface IPool {
   event MintedToTreasury(address indexed reserve, uint256 amountMinted);
 
   /**
-   * @dev Mints an `amount` of aTokens to the `onBehalfOf`
+   * @notice Mints an `amount` of aTokens to the `onBehalfOf`
    * @param asset The address of the underlying asset to mint
    * @param amount The amount to mint
    * @param onBehalfOf The address that will receive the aTokens
@@ -226,16 +226,17 @@ interface IPool {
   ) external;
 
   /**
-   * @dev Back the current unbacked underlying with `amount` and pay `fee`.
+   * @notice Back the current unbacked underlying with `amount` and pay `fee`.
    * @param asset The address of the underlying asset to back
    * @param amount The amount to back
    * @param fee The amount paid in fees
+   * @return The backed amount
    **/
   function backUnbacked(
     address asset,
     uint256 amount,
     uint256 fee
-  ) external;
+  ) external returns (uint256);
 
   /**
    * @notice Supplies an `amount` of underlying asset into the reserve, receiving in return overlying aTokens.

contracts/protocol/libraries/helpers/Errors.sol

@@ -54,7 +54,6 @@ library Errors {
   string public constant HEALTH_FACTOR_NOT_BELOW_THRESHOLD = '45'; // 'Health factor is not below the threshold'
   string public constant COLLATERAL_CANNOT_BE_LIQUIDATED = '46'; // 'The collateral chosen cannot be liquidated'
   string public constant SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER = '47'; // 'User did not borrow the specified currency'
-  string public constant SAME_BLOCK_BORROW_REPAY = '48'; // 'Borrow and repay in same block is not allowed'
   string public constant INCONSISTENT_FLASHLOAN_PARAMS = '49'; // 'Inconsistent flashloan parameters'
   string public constant BORROW_CAP_EXCEEDED = '50'; // 'Borrow cap is exceeded'
   string public constant SUPPLY_CAP_EXCEEDED = '51'; // 'Supply cap is exceeded'

contracts/protocol/libraries/logic/BridgeLogic.sol

@@ -100,20 +100,22 @@ library BridgeLogic {
 
   /**
    * @notice Back the current unbacked with `amount` and pay `fee`.
+   * @dev It is not possible to back more than the existing unbacked amount of the reserve
    * @dev Emits the `BackUnbacked` event
    * @param reserve The reserve to back unbacked for
    * @param asset The address of the underlying asset to repay
    * @param amount The amount to back
    * @param fee The amount paid in fees
    * @param protocolFeeBps The fraction of fees in basis points paid to the protocol
+   * @return The backed amount
    **/
   function executeBackUnbacked(
     DataTypes.ReserveData storage reserve,
     address asset,
     uint256 amount,
     uint256 fee,
     uint256 protocolFeeBps
-  ) external {
+  ) external returns (uint256) {
     DataTypes.ReserveCache memory reserveCache = reserve.cache();
 
     reserve.updateState(reserveCache);
@@ -137,5 +139,7 @@ library BridgeLogic {
     IERC20(asset).safeTransferFrom(msg.sender, reserveCache.aTokenAddress, added);
 
     emit BackUnbacked(asset, msg.sender, backingAmount, fee);
+
+    return backingAmount;
   }
 }

contracts/protocol/libraries/logic/LiquidationLogic.sol

@@ -166,6 +166,13 @@ library LiquidationLogic {
       userConfig.setBorrowing(debtReserve.id, false);
     }
 
+    // If the collateral being liquidated is equal to the user balance,
+    // we set the currency as not being used as collateral anymore
+    if (vars.actualCollateralToLiquidate == vars.userCollateralBalance) {
+      userConfig.setUsingAsCollateral(collateralReserve.id, false);
+      emit ReserveUsedAsCollateralDisabled(params.collateralAsset, params.user);
+    }
+
     _burnDebtTokens(params, vars);
 
     debtReserve.updateInterestRates(
@@ -197,14 +204,7 @@ library LiquidationLogic {
         vars.liquidationProtocolFeeAmount
       );
     }
-
-    // If the collateral being liquidated is equal to the user balance,
-    // we set the currency as not being used as collateral anymore
-    if (vars.actualCollateralToLiquidate == vars.userCollateralBalance) {
-      userConfig.setUsingAsCollateral(collateralReserve.id, false);
-      emit ReserveUsedAsCollateralDisabled(params.collateralAsset, params.user);
-    }
-
+
     // Transfers the debt asset being repaid to the aToken, where the liquidity is kept
     IERC20(params.debtAsset).safeTransferFrom(
       msg.sender,

contracts/protocol/libraries/logic/ReserveLogic.sol

@@ -292,7 +292,9 @@ library ReserveLogic {
     DataTypes.ReserveData storage reserve,
     DataTypes.ReserveCache memory reserveCache
   ) internal {
-    //only cumulating if there is any income being produced
+    // Only cumulating on the supply side if there is any income being produced
+    // The case of Reserve Factor 100% is not a problem (currentLiquidityRate == 0),
+    // as liquidity index should not be updated
     if (reserveCache.currLiquidityRate != 0) {
       uint256 cumulatedLiquidityInterest = MathUtils.calculateLinearInterest(
         reserveCache.currLiquidityRate,
@@ -302,19 +304,21 @@ library ReserveLogic {
         reserveCache.currLiquidityIndex
       );
       reserve.liquidityIndex = reserveCache.nextLiquidityIndex.toUint128();
+    }
 
-      //as the liquidity rate might come only from stable rate loans, we need to ensure
-      //that there is actual variable debt before accumulating
-      if (reserveCache.currScaledVariableDebt != 0) {
-        uint256 cumulatedVariableBorrowInterest = MathUtils.calculateCompoundedInterest(
-          reserveCache.currVariableBorrowRate,
-          reserveCache.reserveLastUpdateTimestamp
-        );
-        reserveCache.nextVariableBorrowIndex = cumulatedVariableBorrowInterest.rayMul(
-          reserveCache.currVariableBorrowIndex
-        );
-        reserve.variableBorrowIndex = reserveCache.nextVariableBorrowIndex.toUint128();
-      }
+    // Variable borrow index only gets updated if there is any variable debt.
+    // reserveCache.currVariableBorrowRate != 0 is not a correct validation,
+    // because a positive base variable rate can be stored on
+    // reserveCache.currVariableBorrowRate, but the index should not increase
+    if (reserveCache.currScaledVariableDebt != 0) {
+      uint256 cumulatedVariableBorrowInterest = MathUtils.calculateCompoundedInterest(
+        reserveCache.currVariableBorrowRate,
+        reserveCache.reserveLastUpdateTimestamp
+      );
+      reserveCache.nextVariableBorrowIndex = cumulatedVariableBorrowInterest.rayMul(
+        reserveCache.currVariableBorrowIndex
+      );
+      reserve.variableBorrowIndex = reserveCache.nextVariableBorrowIndex.toUint128();
     }
   }
 

contracts/protocol/libraries/logic/SupplyLogic.sol

@@ -128,32 +128,32 @@ library SupplyLogic {
 
     reserve.updateInterestRates(reserveCache, params.asset, 0, amountToWithdraw);
 
+    bool isCollateral = userConfig.isUsingAsCollateral(reserve.id);
+
+    if (isCollateral && amountToWithdraw == userBalance) {
+      userConfig.setUsingAsCollateral(reserve.id, false);
+      emit ReserveUsedAsCollateralDisabled(params.asset, msg.sender);
+    }
+
     IAToken(reserveCache.aTokenAddress).burn(
       msg.sender,
       params.to,
       amountToWithdraw,
       reserveCache.nextLiquidityIndex
     );
 
-    if (userConfig.isUsingAsCollateral(reserve.id)) {
-      if (userConfig.isBorrowingAny()) {
-        ValidationLogic.validateHFAndLtv(
-          reservesData,
-          reservesList,
-          eModeCategories,
-          userConfig,
-          params.asset,
-          msg.sender,
-          params.reservesCount,
-          params.oracle,
-          params.userEModeCategory
-        );
-      }
-
-      if (amountToWithdraw == userBalance) {
-        userConfig.setUsingAsCollateral(reserve.id, false);
-        emit ReserveUsedAsCollateralDisabled(params.asset, msg.sender);
-      }
+    if (isCollateral && userConfig.isBorrowingAny()) {
+      ValidationLogic.validateHFAndLtv(
+        reservesData,
+        reservesList,
+        eModeCategories,
+        userConfig,
+        params.asset,
+        msg.sender,
+        params.reservesCount,
+        params.oracle,
+        params.userEModeCategory
+      );
     }
 
     emit Withdraw(params.asset, msg.sender, params.to, amountToWithdraw);
@@ -264,7 +264,12 @@ library SupplyLogic {
 
     if (useAsCollateral) {
       require(
-        ValidationLogic.validateUseAsCollateral(reservesData, reservesList, userConfig, reserveCache.reserveConfiguration),
+        ValidationLogic.validateUseAsCollateral(
+          reservesData,
+          reservesList,
+          userConfig,
+          reserveCache.reserveConfiguration
+        ),
         Errors.USER_IN_ISOLATION_MODE
       );
 

contracts/protocol/libraries/logic/ValidationLogic.sol

@@ -327,20 +327,6 @@ library ValidationLogic {
     require(isActive, Errors.RESERVE_INACTIVE);
     require(!isPaused, Errors.RESERVE_PAUSED);
 
-    uint256 variableDebtPreviousIndex = IScaledBalanceToken(reserveCache.variableDebtTokenAddress)
-      .getPreviousIndex(onBehalfOf);
-
-    uint40 stableRatePreviousTimestamp = IStableDebtToken(reserveCache.stableDebtTokenAddress)
-      .getUserLastUpdated(onBehalfOf);
-
-    require(
-      (stableRatePreviousTimestamp < uint40(block.timestamp) &&
-        interestRateMode == DataTypes.InterestRateMode.STABLE) ||
-        (variableDebtPreviousIndex < reserveCache.nextVariableBorrowIndex &&
-          interestRateMode == DataTypes.InterestRateMode.VARIABLE),
-      Errors.SAME_BLOCK_BORROW_REPAY
-    );
-
     require(
       (stableDebt != 0 && interestRateMode == DataTypes.InterestRateMode.STABLE) ||
         (variableDebt != 0 && interestRateMode == DataTypes.InterestRateMode.VARIABLE),

contracts/protocol/pool/Pool.sol

@@ -136,8 +136,9 @@ contract Pool is VersionedInitializable, PoolStorage, IPool {
     address asset,
     uint256 amount,
     uint256 fee
-  ) external virtual override onlyBridge {
-    BridgeLogic.executeBackUnbacked(_reserves[asset], asset, amount, fee, _bridgeProtocolFee);
+  ) external virtual override onlyBridge returns (uint256) {
+    return
+      BridgeLogic.executeBackUnbacked(_reserves[asset], asset, amount, fee, _bridgeProtocolFee);
   }
 
   /// @inheritdoc IPool

contracts/protocol/tokenization/AToken.sol

@@ -107,7 +107,7 @@ contract AToken is VersionedInitializable, ScaledBalanceTokenBase, EIP712Base, I
   }
 
   /// @inheritdoc IAToken
-  function mintToTreasury(uint256 amount, uint256 index) external override onlyPool {
+  function mintToTreasury(uint256 amount, uint256 index) external virtual override onlyPool {
     if (amount == 0) {
       return;
     }
@@ -119,7 +119,7 @@ contract AToken is VersionedInitializable, ScaledBalanceTokenBase, EIP712Base, I
     address from,
     address to,
     uint256 value
-  ) external override onlyPool {
+  ) external virtual override onlyPool {
     // Being a normal transfer, the Transfer() and BalanceTransfer() are emitted
     // so no need to emit a specific event here
     _transfer(from, to, value, false);

helpers/types.ts

@@ -118,7 +118,6 @@ export enum ProtocolErrors {
   HEALTH_FACTOR_NOT_BELOW_THRESHOLD = '45', // 'Health factor is not below the threshold'
   COLLATERAL_CANNOT_BE_LIQUIDATED = '46', // 'The collateral chosen cannot be liquidated'
   SPECIFIED_CURRENCY_NOT_BORROWED_BY_USER = '47', // 'User did not borrow the specified currency'
-  SAME_BLOCK_BORROW_REPAY = '48', // 'Borrow and repay in same block is not allowed'
   INCONSISTENT_FLASHLOAN_PARAMS = '49', // 'Inconsistent flashloan parameters'
   BORROW_CAP_EXCEEDED = '50', // 'Borrow cap is exceeded'
   SUPPLY_CAP_EXCEEDED = '51', // 'Supply cap is exceeded'