Initial commit

contracts/lendingpool/LendingPoolConfigurator.sol

@@ -14,7 +14,7 @@ import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddresses
 import {ILendingPool} from '../interfaces/ILendingPool.sol';
 import {IERC20Detailed} from '../interfaces/IERC20Detailed.sol';
 import {Errors} from '../libraries/helpers/Errors.sol';
-
+import {PercentageMath} from '../libraries/math/PercentageMath.sol';
 /**
  * @title LendingPoolConfigurator contract
  * @author Aave
@@ -56,25 +56,19 @@ contract LendingPoolConfigurator is VersionedInitializable {
   event BorrowingDisabledOnReserve(address indexed asset);
 
   /**
-   * @dev emitted when a reserve is enabled as collateral.
+   * @dev emitted when a a reserve collateralization risk parameters are updated.
    * @param asset the address of the reserve
    * @param ltv the loan to value of the asset when used as collateral
    * @param liquidationThreshold the threshold at which loans using this asset as collateral will be considered undercollateralized
    * @param liquidationBonus the bonus liquidators receive to liquidate this asset
    **/
-  event ReserveEnabledAsCollateral(
+  event CollateralConfigurationChanged(
     address indexed asset,
     uint256 ltv,
     uint256 liquidationThreshold,
     uint256 liquidationBonus
   );
 
-  /**
-   * @dev emitted when a reserve is disabled as collateral
-   * @param asset the address of the reserve
-   **/
-  event ReserveDisabledAsCollateral(address indexed asset);
-
   /**
    * @dev emitted when stable rate borrowing is enabled on a reserve
    * @param asset the address of the reserve
@@ -326,41 +320,45 @@ contract LendingPoolConfigurator is VersionedInitializable {
   }
 
   /**
-   * @dev enables a reserve to be used as collateral
+   * @dev configures the reserve collateralization parameters 
    * @param asset the address of the reserve
    * @param ltv the loan to value of the asset when used as collateral
    * @param liquidationThreshold the threshold at which loans using this asset as collateral will be considered undercollateralized
    * @param liquidationBonus the bonus liquidators receive to liquidate this asset
    **/
-  function enableReserveAsCollateral(
+  function configureReserveAsCollateral(
     address asset,
     uint256 ltv,
     uint256 liquidationThreshold,
     uint256 liquidationBonus
   ) external onlyAaveAdmin {
+
     ReserveConfiguration.Map memory currentConfig = pool.getConfiguration(asset);
 
+    //validation of the parameters: the LTV can 
+    //only be lower or equal than the liquidation threshold 
+    //(otherwise a loan against the asset would cause instantaneous liquidation)
+    require(ltv <= liquidationThreshold, Errors.INVALID_CONFIGURATION);
+
+    //liquidation bonus must be bigger than 100.00%, otherwise the liquidator would receive less
+    //collateral than needed to repay the debt
+    require(liquidationBonus > PercentageMath.PERCENTAGE_FACTOR, Errors.INVALID_CONFIGURATION);
+    
+
+    //if the liquidation threshold is being set to 0,
+    // the reserve is being disabled as collateral. To do so,
+    //we need to ensure no liquidity is deposited 
+    if(liquidationThreshold == 0) {
+      _checkNoLiquidity(asset);
+    }
+
     currentConfig.setLtv(ltv);
     currentConfig.setLiquidationThreshold(liquidationThreshold);
     currentConfig.setLiquidationBonus(liquidationBonus);
 
     pool.setConfiguration(asset, currentConfig.data);
 
-    emit ReserveEnabledAsCollateral(asset, ltv, liquidationThreshold, liquidationBonus);
-  }
-
-  /**
-   * @dev disables a reserve as collateral
-   * @param asset the address of the reserve
-   **/
-  function disableReserveAsCollateral(address asset) external onlyAaveAdmin {
-    ReserveConfiguration.Map memory currentConfig = pool.getConfiguration(asset);
-
-    currentConfig.setLtv(0);
-
-    pool.setConfiguration(asset, currentConfig.data);
-
-    emit ReserveDisabledAsCollateral(asset);
+    emit CollateralConfigurationChanged(asset, ltv, liquidationThreshold, liquidationBonus);
   }
 
   /**
@@ -410,22 +408,8 @@ contract LendingPoolConfigurator is VersionedInitializable {
    * @param asset the address of the reserve
    **/
   function deactivateReserve(address asset) external onlyAaveAdmin {
-    (
-      uint256 availableLiquidity,
-      uint256 totalStableDebt,
-      uint256 totalVariableDebt,
-      ,
-      ,
-      ,
-      ,
-      ,
-      ,
-
-    ) = pool.getReserveData(asset);
-    require(
-      availableLiquidity == 0 && totalStableDebt == 0 && totalVariableDebt == 0,
-      Errors.RESERVE_LIQUIDITY_NOT_0
-    );
+    
+    _checkNoLiquidity(asset);
 
     ReserveConfiguration.Map memory currentConfig = pool.getConfiguration(asset);
 
@@ -601,4 +585,23 @@ contract LendingPoolConfigurator is VersionedInitializable {
   function setPoolPause(bool val) external onlyAaveAdmin {
     pool.setPause(val);
   }
+
+  function _checkNoLiquidity(address asset) internal view {
+    (
+      uint256 availableLiquidity,
+      uint256 totalStableDebt,
+      uint256 totalVariableDebt,
+      ,
+      ,
+      ,
+      ,
+      ,
+      ,
+
+    ) = pool.getReserveData(asset);
+    require(
+      availableLiquidity == 0 && totalStableDebt == 0 && totalVariableDebt == 0,
+      Errors.RESERVE_LIQUIDITY_NOT_0
+    );
+  }
 }

contracts/libraries/helpers/Errors.sol

@@ -61,6 +61,7 @@ library Errors {
   //require error messages - LendingPoolConfiguration
   string public constant CALLER_NOT_AAVE_ADMIN = '35'; // 'The caller must be the aave admin'
   string public constant RESERVE_LIQUIDITY_NOT_0 = '36'; // 'The liquidity of the reserve needs to be 0'
+  string public constant INVALID_CONFIGURATION = '52'; // 'Invalid risk parameters for the reserve'
 
   //require error messages - LendingPoolAddressesProviderRegistry
   string public constant PROVIDER_NOT_REGISTERED = '37'; // 'Provider is not registered'

test/configurator.spec.ts

@@ -104,7 +104,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
 
   it('Deactivates the ETH reserve as collateral', async () => {
     const {configurator, pool, weth} = testEnv;
-    await configurator.disableReserveAsCollateral(weth.address);
+    await configurator.configureReserveAsCollateral(weth.address, 0, 0, 0);
     const {usageAsCollateralEnabled} = await pool.getReserveConfigurationData(weth.address);
     expect(usageAsCollateralEnabled).to.be.equal(false);
   });