Updating Core smart contracts to Solidity 0.8

.github/workflows/celo-monorepo.yml

@@ -24,7 +24,7 @@ defaults:
 
 env:
   # Increment these to force cache rebuilding
-  NODE_MODULE_CACHE_VERSION: 7
+  NODE_MODULE_CACHE_VERSION: 8
   NODE_OPTIONS: '--max-old-space-size=4096'
   TERM: dumb
   GRADLE_OPTS: '-Dorg.gradle.daemon=false -Dorg.gradle.parallel=false -Dorg.gradle.configureondemand=true -Dorg.gradle.jvmargs="-Xmx4096m -XX:+HeapDumpOnOutOfMemoryError"'

.gitmodules

@@ -7,6 +7,9 @@
 [submodule "packages/protocol/lib/mento-core"]
 	path = packages/protocol/lib/mento-core
 	url = https://github.com/mento-protocol/mento-core
+[submodule "packages/protocol/lib/solidity-bytes-utils.sol"]
+	path = packages/protocol/lib/solidity-bytes-utils.sol
+	url = https://github.com/GNSPS/solidity-bytes-utils
 [submodule "packages/protocol/lib/memview.sol"]
 	path = packages/protocol/lib/memview.sol
 	url = https://github.com/summa-tx/memview.sol

packages/protocol/contractPackages.ts

@@ -48,7 +48,7 @@ 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', 'CeloDistributionSchedule'],
+  contracts: ['GasPriceMinimum', 'FeeCurrencyDirectory', 'CeloDistributionSchedule', 'Proposals', 'LockedGold', 'GoldToken', 'Governance', 'Election', 'Validators', 'Attestations', 'Escrow', 'Random', 'ReleaseGold', 'Freezer', 'MultiSig', 'FeeCurrencyWhitelist', 'FeeHandler', 'MentoFeeHandlerSeller', 'UniswapFeeHandlerSeller', 'Accounts', 'DoubleSigningSlasher', 'DowntimeSlasher', 'EpochRewards', 'GovernanceApproverMultiSig', 'Signatures', 'AttestationsTest', 'FederatedAttestations'],
   proxyContracts: [
     'GasPriceMinimumProxy',
     'FeeCurrencyDirectoryProxy',

packages/protocol/contracts/common/Accounts.sol → packages/protocol/contracts-0.8/common/Accounts.sol

@@ -1,17 +1,18 @@
-pragma solidity ^0.5.13;
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.7 <0.8.20;
 
-import "openzeppelin-solidity/contracts/math/SafeMath.sol";
-import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
+import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
+import "@openzeppelin/contracts8/access/Ownable.sol";
 
-import "./interfaces/IAccounts.sol";
+import "../../contracts/common/interfaces/IAccounts.sol";
 
-import "../common/FixidityLib.sol";
-import "../common/Initializable.sol";
-import "../common/interfaces/ICeloVersionedContract.sol";
+import "../../contracts/common/FixidityLib.sol";
+import "../../contracts/common/Initializable.sol";
+import "../../contracts/common/interfaces/ICeloVersionedContract.sol";
 import "../common/Signatures.sol";
 import "../common/UsingRegistry.sol";
-import "../common/libraries/ReentrancyGuard.sol";
-import "../../contracts-0.8/common/IsL2Check.sol";
+import "../../contracts/common/libraries/ReentrancyGuard.sol";
+import "../common/IsL2Check.sol";
 
 contract Accounts is
   IAccounts,
@@ -198,7 +199,7 @@ contract Accounts is
     uint256 lastIndex = offchainStorageRoots[msg.sender].length - 1;
     bytes memory url = offchainStorageRoots[msg.sender][index];
     offchainStorageRoots[msg.sender][index] = offchainStorageRoots[msg.sender][lastIndex];
-    offchainStorageRoots[msg.sender].length--;
+    offchainStorageRoots[msg.sender].pop();
     emit OffchainStorageRootRemoved(msg.sender, url, index);
   }
 
@@ -986,7 +987,7 @@ contract Accounts is
   function _setEip712DomainSeparator() internal {
     uint256 chainId;
     assembly {
-      chainId := chainid
+      chainId := chainid()
     }
 
     eip712DomainSeparator = keccak256(

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

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: UNLICENSED
+// SPDX-License-Identifier: LGPL-3.0-only
 pragma solidity >=0.8.7 <0.8.20;
 
 import "@openzeppelin/contracts8/security/ReentrancyGuard.sol";

packages/protocol/contracts/common/ExternalCall.sol → packages/protocol/contracts-0.8/common/ExternalCall.sol

@@ -1,6 +1,7 @@
-pragma solidity ^0.5.13;
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.7 <0.8.20;
 
-import "openzeppelin-solidity/contracts/utils/Address.sol";
+import "@openzeppelin/contracts8/utils/Address.sol";
 
 library ExternalCall {
   /**
@@ -18,7 +19,7 @@ library ExternalCall {
     if (data.length > 0) require(Address.isContract(destination), "Invalid contract address");
     bool success;
     bytes memory returnData;
-    (success, returnData) = destination.call.value(value)(data);
+    (success, returnData) = destination.call{ value: value }(data);
     require(success, "Transaction execution failed.");
     return returnData;
   }

packages/protocol/contracts/common/FeeCurrencyWhitelist.sol → packages/protocol/contracts-0.8/common/FeeCurrencyWhitelist.sol

@@ -1,12 +1,12 @@
-pragma solidity ^0.5.13;
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.7 <0.8.20;
 
-import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
+import "@openzeppelin/contracts8/access/Ownable.sol";
 
-import "./interfaces/IFeeCurrencyWhitelist.sol";
+import "../../contracts/common/Initializable.sol";
 
-import "../common/Initializable.sol";
-
-import "../common/interfaces/ICeloVersionedContract.sol";
+import "../../contracts/common/interfaces/ICeloVersionedContract.sol";
+import "../../contracts/common/interfaces/IFeeCurrencyWhitelist.sol";
 
 /**
  * @title Holds a whitelist of the ERC20+ tokens that can be used to pay for gas

packages/protocol/contracts/common/FeeHandler.sol → packages/protocol/contracts-0.8/common/FeeHandler.sol

@@ -1,27 +1,27 @@
-pragma solidity ^0.5.13;
-
-import "openzeppelin-solidity/contracts/math/SafeMath.sol";
-import "openzeppelin-solidity/contracts/math/Math.sol";
-import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
-import "openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";
-import "openzeppelin-solidity/contracts/utils/EnumerableSet.sol";
-
-import "./UsingRegistry.sol";
-import "../common/Freezable.sol";
-import "../common/FixidityLib.sol";
-import "../common/Initializable.sol";
-
-import "../common/interfaces/IFeeHandler.sol";
-import "../common/interfaces/IFeeHandlerSeller.sol";
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.7 <0.8.20;
+
+import "@openzeppelin/contracts8/access/Ownable.sol";
+import "@openzeppelin/contracts8/utils/math/Math.sol";
+import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
+import "@openzeppelin/contracts8/utils/structs/EnumerableSet.sol";
+import "@openzeppelin/contracts8/interfaces/IERC20.sol";
+
+import "../../contracts-0.8/common/UsingRegistry.sol";
+import "../../contracts-0.8/common/Freezable.sol";
+import "../../contracts/common/FixidityLib.sol";
+import "../../contracts/common/Initializable.sol";
+import "../../contracts/common/interfaces/IFeeHandler.sol";
+import "../../contracts/common/interfaces/IFeeHandlerSeller.sol";
+import "../../contracts/common/interfaces/ICeloVersionedContract.sol";
+import "../../contracts/common/interfaces/IStableTokenMento.sol";
+import "../../contracts/stability/interfaces/ISortedOracles.sol";
 
 // TODO move to IStableToken when it adds method getExchangeRegistryId
-import "./interfaces/IStableTokenMento.sol";
-import "../common/interfaces/ICeloVersionedContract.sol";
-import "../common/interfaces/ICeloToken.sol";
-import "../stability/interfaces/ISortedOracles.sol";
+import "../../contracts/common/interfaces/ICeloToken.sol";
 
 // Using the minimal required signatures in the interfaces so more contracts could be compatible
-import "../common/libraries/ReentrancyGuard.sol";
+import "../../contracts/common/libraries/ReentrancyGuard.sol";
 
 // An implementation of FeeHandler as described in CIP-52
 // See https://github.com/celo-org/celo-proposals/blob/master/CIPs/cip-0052.md
@@ -119,7 +119,7 @@ contract FeeHandler is
   }
 
   // Without this the contract cant receive Celo as native transfer
-  function() external payable {}
+  receive() external payable {}
 
   /**
     @dev Sets the fee beneficiary address to the specified address.
@@ -342,7 +342,7 @@ contract FeeHandler is
       return false;
     }
 
-    uint256 currentDay = now / 1 days;
+    uint256 currentDay = block.timestamp / 1 days;
     // Pattern borrowed from Reserve.sol
     if (currentDay > lastLimitDay) {
       lastLimitDay = currentDay;
@@ -353,7 +353,7 @@ contract FeeHandler is
   }
 
   function getActiveTokens() public view returns (address[] memory) {
-    return activeTokens.values;
+    return activeTokens.values();
   }
 
   function _setFeeBeneficiary(address beneficiary) private {
@@ -497,7 +497,7 @@ contract FeeHandler is
 
   function _distributeAll() private {
     for (uint256 i = 0; i < EnumerableSet.length(activeTokens); i++) {
-      address token = activeTokens.get(i);
+      address token = activeTokens.at(i);
       _distribute(token);
     }
     // distribute Celo
@@ -508,7 +508,7 @@ contract FeeHandler is
     for (uint256 i = 0; i < EnumerableSet.length(activeTokens); i++) {
       // calling _handle would trigger may burn Celo and distributions
       // that can be just batched at the end
-      address token = activeTokens.get(i);
+      address token = activeTokens.at(i);
       _sell(token);
     }
     _distributeAll(); // distributes Celo as well

packages/protocol/contracts/common/FeeHandlerSeller.sol → packages/protocol/contracts-0.8/common/FeeHandlerSeller.sol

@@ -1,15 +1,17 @@
-pragma solidity ^0.5.13;
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.7 <0.8.20;
 
-import "openzeppelin-solidity/contracts/math/SafeMath.sol";
-import "../common/FixidityLib.sol";
-import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
-import "openzeppelin-solidity/contracts/token/ERC20/IERC20.sol";
-import "./UsingRegistry.sol";
-import "../common/Initializable.sol";
+import "@openzeppelin/contracts8/access/Ownable.sol";
+import "@openzeppelin/contracts8/utils/math/SafeMath.sol";
+import "@openzeppelin/contracts8/interfaces/IERC20.sol";
+
+import "../../contracts/common/FixidityLib.sol";
+import "../../contracts-0.8/common/UsingRegistry.sol";
+import "../../contracts/common/Initializable.sol";
 
 // Abstract class for a FeeHandlerSeller, as defined in CIP-52
 // https://github.com/celo-org/celo-proposals/blob/master/CIPs/cip-0052.md
-contract FeeHandlerSeller is Ownable, Initializable, UsingRegistry {
+abstract contract FeeHandlerSeller is Ownable, Initializable, UsingRegistry {
   using SafeMath for uint256;
   using FixidityLib for FixidityLib.Fraction;
 
@@ -41,7 +43,11 @@ contract FeeHandlerSeller is Ownable, Initializable, UsingRegistry {
     @param to The address of the recipient to transfer the tokens to.
     @return A boolean indicating whether the transfer was successful or not.
   */
-  function transfer(address token, uint256 amount, address to) external onlyOwner returns (bool) {
+  function transfer(
+    address token,
+    uint256 amount,
+    address to
+  ) external virtual onlyOwner returns (bool) {
     return IERC20(token).transfer(to, amount);
   }
 

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

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.0 <0.8.20;
+
+import "./UsingRegistry.sol";
+
+contract Freezable is UsingRegistry {
+  // onlyWhenNotFrozen functions can only be called when `frozen` is false, otherwise they will
+  // revert.
+  modifier onlyWhenNotFrozen() {
+    require(!getFreezer().isFrozen(address(this)), "can't call when contract is frozen");
+    _;
+  }
+}

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

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+pragma solidity >=0.8.7 <0.8.20;
+
+import "@openzeppelin/contracts8/access/Ownable.sol";
+
+import "../../contracts/common/Initializable.sol";
+import "../../contracts/common/interfaces/IFreezer.sol";
+
+contract Freezer is Ownable, Initializable, IFreezer {
+  mapping(address => bool) public isFrozen;
+
+  /**
+   * @notice Sets initialized == true on implementation contracts
+   * @param test Set to true to skip implementation initialization
+   */
+  constructor(bool test) public Initializable(test) {}
+
+  function initialize() external initializer {
+    _transferOwnership(msg.sender);
+  }
+
+  /**
+   * @notice Freezes the target contract, disabling `onlyWhenNotFrozen` functions.
+   * @param target The address of the contract to freeze.
+   */
+  function freeze(address target) external onlyOwner {
+    isFrozen[target] = true;
+  }
+
+  /**
+   * @notice Unfreezes the contract, enabling `onlyWhenNotFrozen` functions.
+   * @param target The address of the contract to freeze.
+   */
+  function unfreeze(address target) external onlyOwner {
+    isFrozen[target] = false;
+  }
+}

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

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: UNLICENSED
+// SPDX-License-Identifier: LGPL-3.0-only
 pragma solidity >=0.8.7 <0.8.20;
 
 import "@openzeppelin/contracts8/access/Ownable.sol";