EpochManager use of transient variables (#11235)

* Move to 0.8.25

* update celo-foundry-8

* electable validators to 110

* Gas optimization

* Build fix

* prettify

* yarn lint

.gitmodules

@@ -24,3 +24,6 @@
 	path = packages/protocol/lib/solidity-bytes-utils-8
 	url = https://github.com/GNSPS/solidity-bytes-utils
 	branch = master
+[submodule "packages/protocol/lib/transient-goodies"]
+	path = packages/protocol/lib/transient-goodies
+	url = https://github.com/Philogy/transient-goodies

packages/protocol/contracts-0.8/common/CeloUnreleasedTreasury.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/security/ReentrancyGuard.sol";
 import "@openzeppelin/contracts8/utils/math/Math.sol";

packages/protocol/contracts-0.8/common/EpochManager.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/token/ERC20/IERC20.sol";
 import "@openzeppelin/contracts8/security/ReentrancyGuard.sol";
@@ -13,6 +13,7 @@ import "../../contracts/common/Initializable.sol";
 import "../../contracts/common/interfaces/IEpochManager.sol";
 import "../../contracts/common/interfaces/ICeloVersionedContract.sol";
 import "./interfaces/IEpochManagerInitializer.sol";
+import { tuint256 } from "transient-goodies/TransientPrimitives.sol";
 
 contract EpochManager is
   Initializable,
@@ -44,10 +45,6 @@ contract EpochManager is
     uint256 totalRewardsCarbonFund; // The total carbon offsetting partner reward.
   }
 
-  struct ProcessedGroup {
-    bool processed;
-    uint256 epochRewards;
-  }
   bool public isSystemInitialized;
 
   // the length of an epoch in seconds
@@ -58,7 +55,7 @@ contract EpochManager is
   address public oracleAddress;
   address[] public elected;
 
-  mapping(address => ProcessedGroup) public processedGroups;
+  mapping(address => tuint256) public processedGroups;
 
   EpochProcessState public epochProcessing;
   mapping(uint256 => Epoch) private epochs;
@@ -219,47 +216,29 @@ contract EpochManager is
     require(isOnEpochProcess(), "Epoch process is not started");
     // finalize epoch
     // last block should be the block before and timestamp from previous block
-    epochs[currentEpochNumber].lastBlock = block.number - 1;
+    uint256 currentEpoch = currentEpochNumber;
+    epochs[currentEpoch].lastBlock = block.number - 1;
     // start new epoch
-    currentEpochNumber++;
-    epochs[currentEpochNumber].firstBlock = block.number;
-    epochs[currentEpochNumber].startTimestamp = block.timestamp;
+    currentEpoch++;
+    epochs[currentEpoch].firstBlock = block.number;
+    epochs[currentEpoch].startTimestamp = block.timestamp;
+    currentEpochNumber = currentEpoch;
 
     EpochProcessState storage _epochProcessing = epochProcessing;
 
-    uint256 toProcessGroups = 0;
-    IValidators validators = getValidators();
     IElection election = getElection();
-    IScoreReader scoreReader = getScoreReader();
-    for (uint i = 0; i < elected.length; i++) {
-      address group = validators.getValidatorsGroup(elected[i]);
-      if (!processedGroups[group].processed) {
-        toProcessGroups++;
-        uint256 groupScore = scoreReader.getGroupScore(group);
-        // We need to precompute epoch rewards for each group since computation depends on total active votes for all groups.
-        uint256 epochRewards = election.getGroupEpochRewardsBasedOnScore(
-          group,
-          _epochProcessing.totalRewardsVoter,
-          groupScore
-        );
-        processedGroups[group] = ProcessedGroup(true, epochRewards);
-      }
-    }
+    uint256 toProcessGroups = fillProcessedGroups(election, _epochProcessing);
 
     require(toProcessGroups == groups.length, "number of groups does not match");
 
     for (uint i = 0; i < groups.length; i++) {
-      ProcessedGroup storage processedGroup = processedGroups[groups[i]];
+      uint256 epochRewards = processedGroups[groups[i]].get();
       // checks that group is actually from elected group
-      require(processedGroup.processed, "group not from current elected set");
-      election.distributeEpochRewards(
-        groups[i],
-        processedGroup.epochRewards,
-        lessers[i],
-        greaters[i]
-      );
-
-      delete processedGroups[groups[i]];
+      require(epochRewards > 0, "group not from current elected set");
+      if (epochRewards == type(uint256).max) {
+        continue;
+      }
+      election.distributeEpochRewards(groups[i], epochRewards, lessers[i], greaters[i]);
     }
     getCeloUnreleasedTreasury().release(
       registry.getAddressForOrDie(GOVERNANCE_REGISTRY_ID),
@@ -494,4 +473,36 @@ contract EpochManager is
       CELOequivalent
     );
   }
+
+  /**
+   * @notice Fills the processedGroups mapping with the groups that need to be processed.
+   * @param election The Election contract.
+   * @param _epochProcessing The current epoch processing state.
+   * @return toProcessGroups The number of groups that need to be processed.
+   */
+  function fillProcessedGroups(
+    IElection election,
+    EpochProcessState storage _epochProcessing
+  ) internal returns (uint256 toProcessGroups) {
+    IScoreReader scoreReader = getScoreReader();
+    IValidators validators = getValidators();
+
+    for (uint i = 0; i < elected.length; i++) {
+      address group = validators.getValidatorsGroup(elected[i]);
+      tuint256 storage processedGroup = processedGroups[group];
+      if (processedGroup.get() == 0) {
+        toProcessGroups++;
+        uint256 groupScore = scoreReader.getGroupScore(group);
+        // We need to precompute epoch rewards for each group since computation depends on total active votes for all groups.
+        uint256 epochRewards = election.getGroupEpochRewardsBasedOnScore(
+          group,
+          _epochProcessing.totalRewardsVoter,
+          groupScore
+        );
+
+        // If the group has no votes, we set the rewards to max uint256 so we can recognize that this group should be processed
+        processedGroup.set(epochRewards == 0 ? type(uint256).max : epochRewards);
+      }
+    }
+  }
 }

packages/protocol/contracts-0.8/common/EpochManagerEnabler.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "../common/UsingRegistry.sol";
 import "../common/UsingPrecompiles.sol";

packages/protocol/contracts-0.8/common/GasPriceMinimum.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/access/Ownable.sol";
 

packages/protocol/contracts-0.8/common/IsL2Check.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.5.13 <0.8.20;
+pragma solidity >=0.5.13 <0.9;
 
 /**
  * @title Based on predeploy returns whether this is L1 or L2.

packages/protocol/contracts-0.8/common/ScoreManager.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "../../contracts/common/Initializable.sol";
 import "../../contracts/common/interfaces/ICeloVersionedContract.sol";
@@ -11,14 +11,14 @@ contract ScoreManager is Initializable, Ownable {
     bool exists;
   }
 
-  event GroupScoreSet(address indexed group, uint256 score);
-  event ValidatorScoreSet(address indexed validator, uint256 score);
-
   uint256 private constant FIXED1_UINT = 1e24;
 
   mapping(address => Score) public groupScores;
   mapping(address => Score) public validatorScores;
 
+  event GroupScoreSet(address indexed group, uint256 score);
+  event ValidatorScoreSet(address indexed validator, uint256 score);
+
   /**
    * @notice Sets initialized == true on implementation contracts
    * @param test Set to true to skip implementation initialization

packages/protocol/contracts-0.8/common/UsingPrecompiles.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 // Note: This is not an exact copy of UsingPrecompiles in the contract's folder, but in solidity 0.8
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";

packages/protocol/contracts-0.8/common/UsingRegistry.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 // Note: This is not an exact copy of UsingRegistry or UsingRegistryV2 in the contract's folder
 // because Mento's interfaces still don't support Solidity 0.8

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface ICeloUnreleasedTreasuryInitializer {
   function initialize(address registryAddress) external;

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface IEpochManagerEnablerInitializer {
   function initialize(address registryAddress) external;

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface IEpochManagerInitializer {
   function initialize(address registryAddress, uint256 newEpochDuration) external;

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

@@ -1,4 +1,4 @@
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 // TODO add to GasPrice
 interface IGasPriceMinimum {

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

@@ -1,4 +1,4 @@
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface IGasPriceMinimumInitializer {
   function initialize(

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 /// Possibly not final version
 interface IOracle {

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface IPrecompiles {
   function getEpochSize() external view returns (uint256);

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface IScoreManager {
   function setGroupScore(address group, uint256 score) external;

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 
 interface IScoreManagerInitializer {
   function initialize() external;

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 interface IScoreReader {
   function getValidatorScore(address validator) external view returns (uint256);

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

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 /**
  * @title This interface describes the functions specific to Celo Stable Tokens, and in the

packages/protocol/contracts-0.8/common/linkedlists/AddressLinkedList.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
 

packages/protocol/contracts-0.8/common/linkedlists/IntegerSortedLinkedList.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
 

packages/protocol/contracts-0.8/common/linkedlists/LinkedList.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
 

packages/protocol/contracts-0.8/common/linkedlists/SortedLinkedList.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
 import "./LinkedList.sol";

packages/protocol/contracts-0.8/common/linkedlists/SortedLinkedListWithMedian.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.8.0 <0.8.20;
+pragma solidity >=0.8.0 <0.9;
 
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
 import "./LinkedList.sol";

packages/protocol/contracts-0.8/common/mocks/EpochManager_WithMocks.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "../EpochManager.sol";
 

packages/protocol/contracts-0.8/common/mocks/MockAccounts.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "../../../contracts/common/FixidityLib.sol";
 

packages/protocol/contracts-0.8/common/mocks/MockOracle.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "../../../contracts-0.8/common/FeeCurrencyDirectory.sol";
 

packages/protocol/contracts-0.8/common/test/MockEpochManager.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.5.13 <0.9.0;
+pragma solidity >=0.5.13 <0.9;
 // solhint-disable no-unused-vars
 
 import "../../../contracts/common/interfaces/IEpochManager.sol";

packages/protocol/contracts-0.8/common/test/MockRegistry.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
 import "@openzeppelin/contracts8/access/Ownable.sol";

packages/protocol/contracts-0.8/governance/Validators.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/access/Ownable.sol";
 import "@openzeppelin/contracts8/utils/math/Math.sol";

packages/protocol/contracts-0.8/governance/test/EpochRewardsMock.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: UNLICENSED
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "../../../contracts/governance/interfaces/IEpochRewards.sol";
 

packages/protocol/contracts-0.8/governance/test/IMockValidators.sol

@@ -1,4 +1,4 @@
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 interface IMockValidators {
   function isValidator(address) external returns (bool);

packages/protocol/contracts-0.8/stability/CeloFeeCurrencyAdapterOwnable.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "./FeeCurrencyAdapterOwnable.sol";
 

packages/protocol/contracts-0.8/stability/FeeCurrencyAdapter.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/access/Ownable.sol";
 import "@openzeppelin/contracts8/token/ERC20/IERC20.sol";

packages/protocol/contracts-0.8/stability/FeeCurrencyAdapterOwnable.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 import "@openzeppelin/contracts8/access/Ownable.sol";
 import "@openzeppelin/contracts8/token/ERC20/IERC20.sol";

packages/protocol/contracts-0.8/stability/interfaces/IFeeCurrencyAdapter.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity >=0.8.7 <0.8.20;
+pragma solidity >=0.8.7 <0.9;
 
 interface IFeeCurrencyAdapter {
   /**