Merge branch 'feat/debt-token-fixes' into 'master'

Debt token fixes

See merge request aave-tech/protocol-v2!21

contracts/tokenization/StableDebtToken.sol

@@ -42,7 +42,7 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
    * @param _balanceIncrease the debt increase since the last update
    * @param _newRate the rate of the debt after the minting
    **/
-  event mintDebt(
+  event MintDebt(
     address _user,
     uint256 _amount,
     uint256 _previousBalance,
@@ -59,7 +59,7 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
    * @param _currentBalance the current balance of the user
    * @param _balanceIncrease the debt increase since the last update
    **/
-  event burnDebt(
+  event BurnDebt(
     address _user,
     uint256 _amount,
     uint256 _previousBalance,
@@ -178,7 +178,7 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
 
     _mint(_user, _amount.add(balanceIncrease));
 
-    emit mintDebt(
+    emit MintDebt(
       _user,
       _amount,
       previousBalance,
@@ -203,16 +203,12 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
     uint256 supplyBeforeBurn = totalSupply.add(balanceIncrease);
     uint256 supplyAfterBurn = supplyBeforeBurn.sub(_amount);
 
-    uint256 newSupply = totalSupply.add(balanceIncrease).sub(_amount);
+    if (supplyAfterBurn == 0) {
-
-    uint256 amountInRay = _amount.wadToRay();
-
-    if (newSupply == 0) {
       avgStableRate = 0;
     } else {
       avgStableRate = avgStableRate
         .rayMul(supplyBeforeBurn.wadToRay())
-        .sub(usersData[_user].currentRate.rayMul(amountInRay))
+        .sub(usersData[_user].currentRate.rayMul(_amount.wadToRay()))
         .rayDiv(supplyAfterBurn.wadToRay());
     }
 
@@ -227,36 +223,6 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
       _burn(_user, _amount.sub(balanceIncrease));
     }
 
-    emit burnDebt(_user, _amount, previousBalance, currentBalance, balanceIncrease);
+    emit BurnDebt(_user, _amount, previousBalance, currentBalance, balanceIncrease);
-  }
-
-  /**
-   * @dev calculates the increase in balance since the last user action
-   * @param _user the address of the user for which the interest is being accumulated
-   * @return the previous principal balance, the new principal balance, the balance increase
-   **/
-  function _calculateBalanceIncrease(address _user)
-    internal
-    view
-    returns (
-      uint256,
-      uint256,
-      uint256
-    )
-  {
-    uint256 previousPrincipalBalance = balances[_user];
-
-    if (previousPrincipalBalance == 0) {
-      return (0, 0, 0);
-    }
-
-    //calculate the accrued interest since the last accumulation
-    uint256 balanceIncrease = balanceOf(_user).sub(previousPrincipalBalance);
-
-    return (
-      previousPrincipalBalance,
-      previousPrincipalBalance.add(balanceIncrease),
-      balanceIncrease
-    );
   }
 }

contracts/tokenization/VariableDebtToken.sol

@@ -31,7 +31,7 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
    * @param _balanceIncrease the debt accumulated since the last action
    * @param _index the index of the user
    **/
-  event mintDebt(
+  event MintDebt(
     address _user,
     uint256 _amount,
     uint256 _previousBalance,
@@ -49,7 +49,7 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
    * @param _balanceIncrease the debt accumulated since the last action
    * @param _index the index of the user
    **/
-  event burnDebt(
+  event BurnDebt(
     address _user,
     uint256 _amount,
     uint256 _previousBalance,
@@ -95,7 +95,7 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
    * @return the user index
    **/
 
-  function getUserIndex(address _user) public virtual override view returns (uint256) {
+  function getUserIndex(address _user) external virtual override view returns (uint256) {
     return userIndexes[_user];
   }
 
@@ -104,7 +104,7 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
    * @param _user the user receiving the debt
    * @param _amount the amount of debt being minted
    **/
-  function mint(address _user, uint256 _amount) public override onlyLendingPool {
+  function mint(address _user, uint256 _amount) external override onlyLendingPool {
     (
       uint256 previousBalance,
       uint256 currentBalance,
@@ -113,16 +113,10 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
 
     _mint(_user, _amount.add(balanceIncrease));
 
-    userIndexes[_user] = pool.getReserveNormalizedVariableDebt(underlyingAssetAddress);
+    uint256 newUserIndex = pool.getReserveNormalizedVariableDebt(underlyingAssetAddress);
+    userIndexes[_user] = newUserIndex;
 
-    emit mintDebt(
+    emit MintDebt(_user, _amount, previousBalance, currentBalance, balanceIncrease, newUserIndex);
-      _user,
-      _amount,
-      previousBalance,
-      currentBalance,
-      balanceIncrease,
-      userIndexes[_user]
-    );
   }
 
   /**
@@ -130,7 +124,7 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
    * @param _user the user which debt is burnt
    * @param _amount the amount of debt being burned
    **/
-  function burn(address _user, uint256 _amount) public override onlyLendingPool {
+  function burn(address _user, uint256 _amount) external override onlyLendingPool {
     (
       uint256 previousBalance,
       uint256 currentBalance,
@@ -143,51 +137,13 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
       _burn(_user, _amount.sub(balanceIncrease));
     }
 
-    //if user repaid everything
+    uint256 newUserIndex = 0;
-    if (currentBalance == _amount) {
+    //if user not repaid everything
-      userIndexes[_user] = 0;
+    if (currentBalance != _amount) {
-    } else {
+      newUserIndex = pool.getReserveNormalizedVariableDebt(underlyingAssetAddress);
-      userIndexes[_user] = pool.getReserveNormalizedVariableDebt(underlyingAssetAddress);
     }
+    userIndexes[_user] = newUserIndex;
 
-    emit burnDebt(
+    emit BurnDebt(_user, _amount, previousBalance, currentBalance, balanceIncrease, newUserIndex);
-      _user,
-      _amount,
-      previousBalance,
-      currentBalance,
-      balanceIncrease,
-      userIndexes[_user]
-    );
-  }
-
-  /**
-   * @dev calculates the increase in balance since the last user interaction
-   * @param _user the address of the user for which the interest is being accumulated
-   * @return the previous principal balance, the new principal balance, the balance increase
-   * and the new user index
-   **/
-  function _calculateBalanceIncrease(address _user)
-    internal
-    view
-    returns (
-      uint256,
-      uint256,
-      uint256
-    )
-  {
-    uint256 previousPrincipalBalance = balances[_user];
-
-    if (previousPrincipalBalance == 0) {
-      return (0, 0, 0);
-    }
-
-    //calculate the accrued interest since the last accumulation
-    uint256 balanceIncrease = balanceOf(_user).sub(previousPrincipalBalance);
-
-    return (
-      previousPrincipalBalance,
-      previousPrincipalBalance.add(balanceIncrease),
-      balanceIncrease
-    );
   }
 }

contracts/tokenization/base/DebtTokenBase.sol

@@ -140,4 +140,35 @@ abstract contract DebtTokenBase is IERC20, VersionedInitializable {
   {
     revert('ALLOWANCE_NOT_SUPPORTED');
   }
+
+  /**
+   * @dev calculates the increase in balance since the last user interaction
+   * @param _user the address of the user for which the interest is being accumulated
+   * @return the previous principal balance, the new principal balance, the balance increase
+   * and the new user index
+   **/
+  function _calculateBalanceIncrease(address _user)
+    internal
+    view
+    returns (
+      uint256,
+      uint256,
+      uint256
+    )
+  {
+    uint256 previousPrincipalBalance = balances[_user];
+
+    if (previousPrincipalBalance == 0) {
+      return (0, 0, 0);
+    }
+
+    //calculate the accrued interest since the last accumulation
+    uint256 balanceIncrease = balanceOf(_user).sub(previousPrincipalBalance);
+
+    return (
+      previousPrincipalBalance,
+      previousPrincipalBalance.add(balanceIncrease),
+      balanceIncrease
+    );
+  }
 }