Soloseng/update-celo-L2-distribution-logic (#11045)

* modified L2 CELO distribution logic

* rename functions

* ++ more name changes

* change more variable names

* ∆ gold to celo in contract

* contract rename

* forgotten names

packages/protocol/contractPackages.ts

@@ -48,12 +48,12 @@ export const SOLIDITY_08_PACKAGE = {
   proxiesPath: '/', // Proxies are still with 0.5 contracts
   // Proxies shouldn't have to be added to a list manually
   // https://github.com/celo-org/celo-monorepo/issues/10555
-  contracts: ['GasPriceMinimum', 'FeeCurrencyDirectory', 'MintGoldSchedule'],
+  contracts: ['GasPriceMinimum', 'FeeCurrencyDirectory', 'CeloDistributionSchedule'],
   proxyContracts: [
     'GasPriceMinimumProxy',
     'FeeCurrencyDirectoryProxy',
     'MentoFeeCurrencyAdapterV1',
-    'MintGoldScheduleProxy',
+    'CeloDistributionScheduleProxy',
   ],
   truffleConfig: 'truffle-config0.8.js',
 } satisfies ContractPackage

packages/protocol/contracts-0.8/common/MintGoldSchedule.sol → packages/protocol/contracts-0.8/common/CeloDistributionSchedule.sol

@@ -12,13 +12,13 @@ import "../../contracts/common/Initializable.sol";
 import "../../contracts-0.8/common/interfaces/IGoldToken.sol";
 
 /**
- * @title Contract for minting new CELO token based on a schedule.
+ * @title Contract for distributing CELO token based on a schedule.
  */
-contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2Check {
+contract CeloDistributionSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2Check {
   using FixidityLib for FixidityLib.Fraction;
 
-  uint256 constant GENESIS_GOLD_SUPPLY = 600000000 ether; // 600 million Gold
-  uint256 constant GOLD_SUPPLY_CAP = 1000000000 ether; // 1 billion Gold
+  uint256 constant GENESIS_CELO_SUPPLY = 600000000 ether; // 600 million Celo
+  uint256 constant CELO_SUPPLY_CAP = 1000000000 ether; // 1 billion Celo
   uint256 constant YEARS_LINEAR = 15;
   uint256 constant SECONDS_LINEAR = YEARS_LINEAR * 365 * 1 days;
 
@@ -27,7 +27,7 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
   uint256 public l2StartTime;
   uint256 public totalSupplyAtL2Start;
 
-  uint256 public totalMintedBySchedule;
+  uint256 public totalDistributedBySchedule;
   address public communityRewardFund;
   address public carbonOffsettingPartner;
 
@@ -38,7 +38,7 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
   event CarbonOffsettingFundSet(address indexed partner, uint256 fraction);
 
   modifier whenActivated() {
-    require(areDependenciesSet, "Minting schedule has not been activated.");
+    require(areDependenciesSet, "Distribution schedule has not been activated.");
     _;
   }
 
@@ -49,14 +49,14 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
   constructor(bool test) public Initializable(test) {}
 
   /**
-   * @notice A constructor for initialising a new instance of a MintGoldSchedule contract.
+   * @notice A constructor for initialising a new instance of a CeloDistributionSchedule contract.
    */
   function initialize() external initializer {
     _transferOwnership(msg.sender);
   }
 
   /**
-   * @notice Sets the minting schedule dependencies during L2 transition.
+   * @notice Sets the distribution schedule dependencies during L2 transition.
    * @param _l2StartTime The timestamp of L1 to L2 transition.
    * @param _communityRewardFraction The percentage of rewards that go the community funds.
    * @param _carbonOffsettingPartner The address of the carbon offsetting partner.
@@ -70,6 +70,7 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
     uint256 _carbonOffsettingFraction,
     address registryAddress
   ) external onlyOwner onlyL2 {
+    require(address(this).balance > 0, "Contract does not have CELO balance.");
     require(!areDependenciesSet, "Contract has already been activated.");
     require(registryAddress != address(0), "The registry address cannot be the zero address");
     require(block.timestamp > _l2StartTime, "L2 start time cannot be set to a future date.");
@@ -83,32 +84,38 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
   }
 
   /**
-   * @notice Mints CELO to the community and carbon offsetting funds according to the predefined schedule.
+   * @notice Distributes CELO to the community and carbon offsetting funds according to the predefined schedule.
    */
-  function mintAccordingToSchedule() external nonReentrant onlyL2 returns (bool) {
+  function distributeAccordingToSchedule() external nonReentrant onlyL2 returns (bool) {
     (
-      uint256 targetGoldTotalSupply,
-      uint256 communityRewardFundMintAmount,
-      uint256 carbonOffsettingPartnerMintAmount
-    ) = getTargetGoldTotalSupply();
-
-    uint256 mintableAmount = Math.min(
-      getRemainingBalanceToMint(),
-      targetGoldTotalSupply - getGoldToken().totalSupply()
+      uint256 targetCeloTotalSupply,
+      uint256 communityRewardFundDistributionAmount,
+      uint256 carbonOffsettingPartnerDistributionAmount
+    ) = getTargetCeloTotalSupply();
+
+    uint256 distributableAmount = Math.min(
+      getRemainingBalanceToDistribute(),
+      targetCeloTotalSupply - getGoldToken().totalSupply()
     );
 
-    require(mintableAmount > 0, "Mintable amount must be greater than zero");
-    totalMintedBySchedule += mintableAmount;
+    require(distributableAmount > 0, "Distributable amount must be greater than zero.");
+    require(address(this).balance > distributableAmount, "Contract balance is insufficient.");
 
-    IGoldToken goldToken = IGoldToken(address(getGoldToken()));
+    totalDistributedBySchedule += distributableAmount;
+
+    IGoldToken celoToken = IGoldToken(address(getGoldToken()));
+
+    celoToken.increaseSupply(
+      communityRewardFundDistributionAmount + carbonOffsettingPartnerDistributionAmount
+    );
     require(
-      goldToken.mint(communityRewardFund, communityRewardFundMintAmount),
-      "Failed to mint to community partner."
+      celoToken.transfer(communityRewardFund, communityRewardFundDistributionAmount),
+      "Failed to transfer to community partner."
     );
 
     require(
-      goldToken.mint(carbonOffsettingPartner, carbonOffsettingPartnerMintAmount),
-      "Failed to mint to carbon offsetting partner."
+      celoToken.transfer(carbonOffsettingPartner, carbonOffsettingPartnerDistributionAmount),
+      "Failed to transfer to carbon offsetting partner."
     );
     return true;
   }
@@ -129,6 +136,13 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
     return carbonOffsettingFraction.unwrap();
   }
 
+  /**
+   * @return The total balance distributed by the CeloDistributionSchedule contract.
+   */
+  function getTotalDistributedBySchedule() external view returns (uint256) {
+    return totalDistributedBySchedule;
+  }
+
   /**
    * @notice Returns the storage, major, minor, and patch version of the contract.
    * @return Storage version of the contract.
@@ -200,40 +214,33 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
   }
 
   /**
-   * @notice Calculates remaining CELO balance to mint.
-   * @return The remaining CELO balance to mint.
-   */
-  function getRemainingBalanceToMint() public view returns (uint256) {
-    return GOLD_SUPPLY_CAP - getGoldToken().totalSupply();
-  }
-
-  /**
-   * @return The total balance minted by the MintGoldSchedule contract.
+   * @notice Calculates remaining CELO balance to distribute.
+   * @return The remaining CELO balance to distribute.
    */
-  function getTotalMintedBySchedule() public view returns (uint256) {
-    return totalMintedBySchedule;
+  function getRemainingBalanceToDistribute() public view returns (uint256) {
+    return CELO_SUPPLY_CAP - getGoldToken().totalSupply();
   }
 
   /**
-   * @return The currently mintable amount.
+   * @return The currently distributable amount.
    */
-  function getMintableAmount() public view returns (uint256) {
-    (uint256 targetGoldTotalSupply, , ) = getTargetGoldTotalSupply();
-    return targetGoldTotalSupply - getGoldToken().totalSupply();
+  function getDistributableAmount() public view returns (uint256) {
+    (uint256 targetCeloTotalSupply, , ) = getTargetCeloTotalSupply();
+    return targetCeloTotalSupply - getGoldToken().totalSupply();
   }
 
   /**
    * @notice Returns the target CELO supply according to the target schedule.
-   * @return targetGoldTotalSupply The target total CELO supply according to the target schedule.
-   * @return communityTargetRewards The community reward that can be minted according to the target schedule.
-   * @return carbonFundTargetRewards The carbon offsetting reward that can be minted according to the target schedule.
+   * @return targetCeloTotalSupply The target total CELO supply according to the target schedule.
+   * @return communityTargetRewards The community reward that can be distributed according to the target schedule.
+   * @return carbonFundTargetRewards The carbon offsetting reward that can be distributed according to the target schedule.
    */
-  function getTargetGoldTotalSupply()
+  function getTargetCeloTotalSupply()
     public
     view
     whenActivated
     returns (
-      uint256 targetGoldTotalSupply,
+      uint256 targetCeloTotalSupply,
       uint256 communityTargetRewards,
       uint256 carbonFundTargetRewards
     )
@@ -243,20 +250,20 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
 
     uint256 timeSinceL2Start = block.timestamp - l2StartTime;
     uint256 totalL2LinearSecondsAvailable = SECONDS_LINEAR - (l2StartTime - GENESIS_START_TIME);
-    uint256 mintedOnL1 = totalSupplyAtL2Start - GENESIS_GOLD_SUPPLY;
+    uint256 mintedOnL1 = totalSupplyAtL2Start - GENESIS_CELO_SUPPLY;
 
     bool isLinearDistribution = timeSinceL2Start < totalL2LinearSecondsAvailable;
     if (isLinearDistribution) {
       (
-        targetGoldTotalSupply,
+        targetCeloTotalSupply,
         communityTargetRewards,
         carbonFundTargetRewards
       ) = _calculateTargetReward(timeSinceL2Start, totalL2LinearSecondsAvailable, mintedOnL1);
 
-      return (targetGoldTotalSupply, communityTargetRewards, carbonFundTargetRewards);
+      return (targetCeloTotalSupply, communityTargetRewards, carbonFundTargetRewards);
     } else {
       (
-        targetGoldTotalSupply,
+        targetCeloTotalSupply,
         communityTargetRewards,
         carbonFundTargetRewards
       ) = _calculateTargetReward(
@@ -265,13 +272,13 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
         mintedOnL1
       );
 
-      bool hasNotYetMintedAllLinearRewards = totalMintedBySchedule +
-        GENESIS_GOLD_SUPPLY +
+      bool hasNotYetDistributedAllLinearRewards = totalDistributedBySchedule +
+        GENESIS_CELO_SUPPLY +
         mintedOnL1 <
-        targetGoldTotalSupply;
+        targetCeloTotalSupply;
 
-      if (hasNotYetMintedAllLinearRewards) {
-        return (targetGoldTotalSupply, communityTargetRewards, carbonFundTargetRewards);
+      if (hasNotYetDistributedAllLinearRewards) {
+        return (targetCeloTotalSupply, communityTargetRewards, carbonFundTargetRewards);
       }
       revert("Block reward calculation for years 15-30 unimplemented");
       return (0, 0, 0);
@@ -286,7 +293,7 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
     internal
     view
     returns (
-      uint256 targetGoldTotalSupply,
+      uint256 targetCeloTotalSupply,
       uint256 communityTargetRewards,
       uint256 carbonFundTargetRewards
     )
@@ -296,7 +303,7 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
       _totalL2LinearSecondsAvailable
     );
     // Pay out half of all block rewards linearly.
-    uint256 totalLinearRewards = (GOLD_SUPPLY_CAP - GENESIS_GOLD_SUPPLY) / 2; //(200 million) includes validator rewards.
+    uint256 totalLinearRewards = (CELO_SUPPLY_CAP - GENESIS_CELO_SUPPLY) / 2; //(200 million) includes validator rewards.
 
     FixidityLib.Fraction memory l2LinearRewards = FixidityLib.newFixed(
       totalLinearRewards - _mintedOnL1
@@ -321,10 +328,10 @@ contract MintGoldSchedule is UsingRegistry, ReentrancyGuard, Initializable, IsL2
       .divide(totalL2LinearSecondsAvailableFraction)
       .fromFixed();
 
-    targetGoldTotalSupply =
+    targetCeloTotalSupply =
       communityTargetRewards +
       carbonFundTargetRewards +
-      GENESIS_GOLD_SUPPLY +
+      GENESIS_CELO_SUPPLY +
       _mintedOnL1;
   }
 }

packages/protocol/contracts-0.8/common/interfaces/IMintGoldScheduleInitializer.sol → packages/protocol/contracts-0.8/common/interfaces/ICeloDistributionScheduleInitializer.sol

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: LGPL-3.0-only
 pragma solidity >=0.5.13 <0.9.0;
 
-interface IMintGoldScheduleInitializer {
+interface ICeloDistributionScheduleInitializer {
   function initialize() external;
 }

packages/protocol/contracts-0.8/common/interfaces/IGoldToken.sol

@@ -21,15 +21,23 @@ interface IGoldToken is IERC20 {
   function setRegistry(address registryAddress) external;
 
   /**
-   * @notice Used set the address of the MintGoldSchedule contract.
-   * @param goldTokenMintingScheduleAddress The address of the MintGoldSchedule contract.
+   * @notice Used set the address of the CeloDistributionSchedule contract.
+   * @param celoTokenDistributionScheduleAddress The address of the CeloDistributionSchedule contract.
    */
-  function setGoldTokenMintingScheduleAddress(address goldTokenMintingScheduleAddress) external;
+  function setCeloTokenDistributionScheduleAddress(
+    address celoTokenDistributionScheduleAddress
+  ) external;
 
   /**
    * @dev Mints a new token.
    * @param to The address that will own the minted token.
    * @param value The amount of token to be minted.
    */
   function mint(address to, uint256 value) external returns (bool);
+
+  /**
+   * @notice Increases the variable for total amount of CELO in existence.
+   * @param amount The amount to increase counter by.
+   */
+  function increaseSupply(uint256 amount) external;
 }

packages/protocol/contracts/common/GoldToken.sol

@@ -9,7 +9,7 @@ import "./CalledByVm.sol";
 import "./Initializable.sol";
 import "./interfaces/ICeloToken.sol";
 import "./interfaces/ICeloVersionedContract.sol";
-import "./interfaces/IMintGoldSchedule.sol";
+import "./interfaces/ICeloDistributionSchedule.sol";
 import "../../contracts-0.8/common/IsL2Check.sol";
 
 contract GoldToken is
@@ -37,19 +37,22 @@ contract GoldToken is
   // Burn address is 0xdEaD because truffle is having buggy behaviour with the zero address
   address constant BURN_ADDRESS = address(0x000000000000000000000000000000000000dEaD);
 
-  IMintGoldSchedule public goldTokenMintingSchedule;
+  ICeloDistributionSchedule public celoTokenDistributionSchedule;
 
   event Transfer(address indexed from, address indexed to, uint256 value);
 
   event TransferComment(string comment);
 
   event Approval(address indexed owner, address indexed spender, uint256 value);
 
-  event SetGoldTokenMintingScheduleAddress(address indexed newScheduleAddress);
+  event SetCeloTokenDistributionScheduleAddress(address indexed newScheduleAddress);
 
   modifier onlySchedule() {
     if (isL2()) {
-      require(msg.sender == address(goldTokenMintingSchedule), "Only MintGoldSchedule can call.");
+      require(
+        msg.sender == address(celoTokenDistributionSchedule),
+        "Only CeloDistributionSchedule can call."
+      );
     } else {
       require(msg.sender == address(0), "Only VM can call.");
     }
@@ -73,20 +76,20 @@ contract GoldToken is
   }
 
   /**
-   * @notice Used set the address of the MintGoldSchedule contract.
-   * @param goldTokenMintingScheduleAddress The address of the MintGoldSchedule contract.
+   * @notice Used set the address of the CeloDistributionSchedule contract.
+   * @param celoTokenDistributionScheduleAddress The address of the CeloDistributionSchedule contract.
    */
-  function setGoldTokenMintingScheduleAddress(
-    address goldTokenMintingScheduleAddress
+  function setCeloTokenDistributionScheduleAddress(
+    address celoTokenDistributionScheduleAddress
   ) external onlyOwner {
     require(
-      goldTokenMintingScheduleAddress != address(0) ||
-        goldTokenMintingScheduleAddress != address(goldTokenMintingSchedule),
+      celoTokenDistributionScheduleAddress != address(0) ||
+        celoTokenDistributionScheduleAddress != address(celoTokenDistributionSchedule),
       "Invalid address."
     );
-    goldTokenMintingSchedule = IMintGoldSchedule(goldTokenMintingScheduleAddress);
+    celoTokenDistributionSchedule = ICeloDistributionSchedule(celoTokenDistributionScheduleAddress);
 
-    emit SetGoldTokenMintingScheduleAddress(goldTokenMintingScheduleAddress);
+    emit SetCeloTokenDistributionScheduleAddress(celoTokenDistributionScheduleAddress);
   }
 
   /**
@@ -198,8 +201,9 @@ contract GoldToken is
    * @notice Mints new CELO and gives it to 'to'.
    * @param to The account for which to mint tokens.
    * @param value The amount of CELO to mint.
+   * @dev This function will be deprecated in L2.
    */
-  function mint(address to, uint256 value) external onlySchedule returns (bool) {
+  function mint(address to, uint256 value) external onlyL1 onlyVm returns (bool) {
     if (value == 0) {
       return true;
     }
@@ -221,7 +225,7 @@ contract GoldToken is
    * @dev This function will be deprecated in L2. The onlyway to increase
    * the supply is with the mint function.
    */
-  function increaseSupply(uint256 amount) external onlyL1 onlyVm {
+  function increaseSupply(uint256 amount) external onlySchedule {
     totalSupply_ = totalSupply_.add(amount);
   }