fix: Minimize the IAaveIncentivesController with only the handleAction

Author: miguelmtzinf

contracts/interfaces/IAaveIncentivesController.sol

@@ -5,172 +5,19 @@ pragma solidity ^0.8.0;
  * @title IAaveIncentivesController
  * @author Aave
  * @notice Defines the basic interface for an Aave Incentives Controller.
+ * @dev It only contains one single function, needed as a hook on aToken and debtToken transfers.
  **/
 interface IAaveIncentivesController {
   /**
-   * @dev Emitted during `handleAction`, `claimRewards` and `claimRewardsOnBehalf`
-   * @param user The user that accrued rewards
-   * @param amount The amount of accrued rewards
-   */
-  event RewardsAccrued(address indexed user, uint256 amount);
-
-  event RewardsClaimed(address indexed user, address indexed to, uint256 amount);
-
-  /**
-   * @dev Emitted during `claimRewards` and `claimRewardsOnBehalf`
-   * @param user The address that accrued rewards
-   * @param to The address that will be receiving the rewards
-   * @param claimer The address that performed the claim
-   * @param amount The amount of rewards
-   */
-  event RewardsClaimed(
-    address indexed user,
-    address indexed to,
-    address indexed claimer,
-    uint256 amount
-  );
-
-  /**
-   * @dev Emitted during `setClaimer`
-   * @param user The address of the user
-   * @param claimer The address of the claimer
-   */
-  event ClaimerSet(address indexed user, address indexed claimer);
-
-  /**
-   * @notice Returns the configuration of the distribution for a certain asset
-   * @param asset The address of the reference asset of the distribution
-   * @return The asset index
-   * @return The emission per second
-   * @return The last updated timestamp
-   **/
-  function getAssetData(address asset)
-    external
-    view
-    returns (
-      uint256,
-      uint256,
-      uint256
-    );
-
-  /**
-   * LEGACY **************************
-   * @dev Returns the configuration of the distribution for a certain asset
-   * @param asset The address of the reference asset of the distribution
-   * @return The asset index, the emission per second and the last updated timestamp
-   **/
-  function assets(address asset)
-    external
-    view
-    returns (
-      uint128,
-      uint128,
-      uint256
-    );
-
-  /**
-   * @notice Whitelists an address to claim the rewards on behalf of another address
-   * @param user The address of the user
-   * @param claimer The address of the claimer
-   */
-  function setClaimer(address user, address claimer) external;
-
-  /**
-   * @notice Returns the whitelisted claimer for a certain address (0x0 if not set)
-   * @param user The address of the user
-   * @return The claimer address
-   */
-  function getClaimer(address user) external view returns (address);
-
-  /**
-   * @notice Configure assets for a certain rewards emission
-   * @param assets The assets to incentivize
-   * @param emissionsPerSecond The emission for each asset
-   */
-  function configureAssets(address[] calldata assets, uint256[] calldata emissionsPerSecond)
-    external;
-
-  /**
-   * @notice Called by the corresponding asset on any update that affects the rewards distribution
-   * @param asset The address of the user
-   * @param userBalance The balance of the user of the asset in the pool
-   * @param totalSupply The total supply of the asset in the pool
+   * @dev Called by the corresponding asset on transfer hook in order to update the rewards distribution.
+   * @dev The units of `totalSupply` and `userBalance` should be the same.
+   * @param user The address of the user whose asset balance has changed
+   * @param totalSupply The total supply of the asset prior to user balance change
+   * @param userBalance The previous user balance prior to balance change
    **/
   function handleAction(
-    address asset,
-    uint256 userBalance,
-    uint256 totalSupply
-  ) external;
-
-  /**
-   * @notice Returns the total of rewards of a user, already accrued + not yet accrued
-   * @param assets The assets to accumulate rewards for
-   * @param user The address of the user
-   * @return The rewards
-   **/
-  function getRewardsBalance(address[] calldata assets, address user)
-    external
-    view
-    returns (uint256);
-
-  /**
-   * @notice Claims reward for a user, on the assets of the pool, accumulating the pending rewards
-   * @param assets The assets to accumulate rewards for
-   * @param amount Amount of rewards to claim
-   * @param to Address that will be receiving the rewards
-   * @return Rewards claimed
-   **/
-  function claimRewards(
-    address[] calldata assets,
-    uint256 amount,
-    address to
-  ) external returns (uint256);
-
-  /**
-   * @notice Claims reward for a user on its behalf, on the assets of the pool, accumulating the pending rewards.
-   * @dev The caller must be whitelisted via "allowClaimOnBehalf" function by the RewardsAdmin role manager
-   * @param assets The assets to accumulate rewards for
-   * @param amount The amount of rewards to claim
-   * @param user The address to check and claim rewards
-   * @param to The address that will be receiving the rewards
-   * @return The amount of rewards claimed
-   **/
-  function claimRewardsOnBehalf(
-    address[] calldata assets,
-    uint256 amount,
     address user,
-    address to
-  ) external returns (uint256);
-
-  /**
-   * @notice Returns the unclaimed rewards of the user
-   * @param user The address of the user
-   * @return The unclaimed user rewards
-   */
-  function getUserUnclaimedRewards(address user) external view returns (uint256);
-
-  /**
-   * @notice Returns the user index for a specific asset
-   * @param user The address of the user
-   * @param asset The asset to incentivize
-   * @return The user index for the asset
-   */
-  function getUserAssetData(address user, address asset) external view returns (uint256);
-
-  /**
-   * @notice for backward compatibility with previous implementation of the Incentives controller
-   * @return The address of the reward token
-   */
-  function REWARD_TOKEN() external view returns (address);
-
-  /**
-   * @notice for backward compatibility with previous implementation of the Incentives controller
-   * @return The precision used in the incentives controller
-   */
-  function PRECISION() external view returns (uint8);
-
-  /**
-   * @dev Gets the distribution end timestamp of the emissions
-   */
-  function DISTRIBUTION_END() external view returns (uint256);
+    uint256 totalSupply,
+    uint256 userBalance
+  ) external;
 }

contracts/mocks/helpers/MockIncentivesController.sol

@@ -4,84 +4,9 @@ pragma solidity 0.8.10;
 import {IAaveIncentivesController} from '../../interfaces/IAaveIncentivesController.sol';
 
 contract MockIncentivesController is IAaveIncentivesController {
-  function getAssetData(address)
-    external
-    pure
-    override
-    returns (
-      uint256,
-      uint256,
-      uint256
-    )
-  {
-    return (0, 0, 0);
-  }
-
-  function assets(address)
-    external
-    pure
-    override
-    returns (
-      uint128,
-      uint128,
-      uint256
-    )
-  {
-    return (0, 0, 0);
-  }
-
-  function setClaimer(address, address) external override {}
-
-  function getClaimer(address) external pure override returns (address) {
-    return address(1);
-  }
-
-  function configureAssets(address[] calldata, uint256[] calldata) external override {}
-
   function handleAction(
     address,
     uint256,
     uint256
   ) external override {}
-
-  function getRewardsBalance(address[] calldata, address) external pure override returns (uint256) {
-    return 0;
-  }
-
-  function claimRewards(
-    address[] calldata,
-    uint256,
-    address
-  ) external pure override returns (uint256) {
-    return 0;
-  }
-
-  function claimRewardsOnBehalf(
-    address[] calldata,
-    uint256,
-    address,
-    address
-  ) external pure override returns (uint256) {
-    return 0;
-  }
-
-  function getUserUnclaimedRewards(address) external pure override returns (uint256) {
-    return 0;
-  }
-
-  function getUserAssetData(address, address) external pure override returns (uint256) {
-    return 0;
-  }
-
-  function REWARD_TOKEN() external pure override returns (address) {
-    return address(0);
-  }
-
-  function PRECISION() external pure override returns (uint8) {
-    return 0;
-  }
-
-  function DISTRIBUTION_END() external pure override returns (uint256) {
-    return 0;
-  }
 }

contracts/mocks/upgradeability/MockAToken.sol

@@ -3,7 +3,6 @@ pragma solidity 0.8.10;
 
 import {AToken} from '../../protocol/tokenization/AToken.sol';
 import {IPool} from '../../interfaces/IPool.sol';
-import {IAaveIncentivesController} from '../../interfaces/IAaveIncentivesController.sol';
 
 contract MockAToken is AToken {
   constructor(IPool pool) AToken(pool) {}

contracts/protocol/libraries/logic/ConfiguratorLogic.sol

@@ -4,7 +4,6 @@ pragma solidity 0.8.10;
 import {IPool} from '../../../interfaces/IPool.sol';
 import {IInitializableAToken} from '../../../interfaces/IInitializableAToken.sol';
 import {IInitializableDebtToken} from '../../../interfaces/IInitializableDebtToken.sol';
-import {IAaveIncentivesController} from '../../../interfaces/IAaveIncentivesController.sol';
 import {InitializableImmutableAdminUpgradeabilityProxy} from '../aave-upgradeability/InitializableImmutableAdminUpgradeabilityProxy.sol';
 import {ReserveConfiguration} from '../configuration/ReserveConfiguration.sol';
 import {DataTypes} from '../types/DataTypes.sol';