VAL-114 First cut of adding an upgradeable contract

.gitignore

@@ -21,3 +21,6 @@ typechain-types
 cache
 artifacts
 
+# OpenZeppelin
+.openzeppelin/unknown-*.json
+.openzeppelin/.session

contracts/Pool.sol

@@ -8,25 +8,26 @@ import "./controllers/interfaces/IWithdrawController.sol";
 import "./controllers/interfaces/IPoolController.sol";
 import "./factories/interfaces/IWithdrawControllerFactory.sol";
 import "./factories/interfaces/IPoolControllerFactory.sol";
-import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
-import {IERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import {ERC20Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
+import {IERC20Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
 import {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
-import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import {SafeERC20Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol";
 import {SafeMath} from "@openzeppelin/contracts/utils/math/SafeMath.sol";
 import {Math} from "@openzeppelin/contracts/utils/math/Math.sol";
 import "./libraries/PoolLib.sol";
 import "./FeeVault.sol";
 import "./FirstLossVault.sol";
+import "./upgrades/interfaces/IBeaconImplementation.sol";
 
 /**
  * @title Pool
  */
-contract Pool is IPool, ERC20 {
-    using SafeERC20 for IERC20;
+contract Pool is IPool, ERC20Upgradeable, IBeaconImplementation {
+    using SafeERC20Upgradeable for IERC20Upgradeable;
     using SafeMath for uint256;
     using EnumerableSet for EnumerableSet.AddressSet;
 
-    IERC20 private _liquidityAsset;
+    IERC20Upgradeable private _liquidityAsset;
     FeeVault private _feeVault;
     IPoolAccountings private _accountings;
 
@@ -105,7 +106,7 @@ contract Pool is IPool, ERC20 {
     }
 
     /**
-     * @dev Constructor for Pool
+     * @dev Initializer for Pool
      * @param liquidityAsset asset held by the poo
      * @param poolAdmin admin of the pool
      * @param serviceConfiguration address of global service configuration
@@ -114,7 +115,7 @@ contract Pool is IPool, ERC20 {
      * @param tokenName Name used for issued pool tokens
      * @param tokenSymbol Symbol used for issued pool tokens
      */
-    constructor(
+    function initialize(
         address liquidityAsset,
         address poolAdmin,
         address serviceConfiguration,
@@ -123,8 +124,9 @@ contract Pool is IPool, ERC20 {
         IPoolConfigurableSettings memory poolSettings,
         string memory tokenName,
         string memory tokenSymbol
-    ) ERC20(tokenName, tokenSymbol) {
-        _liquidityAsset = IERC20(liquidityAsset);
+    ) public initializer {
+        __ERC20_init(tokenName, tokenSymbol);
+        _liquidityAsset = IERC20Upgradeable(liquidityAsset);
         _feeVault = new FeeVault(address(this));
 
         // Build the withdraw controller
@@ -366,7 +368,7 @@ contract Pool is IPool, ERC20 {
         );
 
         _accountings.fixedFeeDueDate += fixedFeeInterval * 1 days;
-        IERC20(_liquidityAsset).safeTransfer(recipient, fixedFee);
+        IERC20Upgradeable(_liquidityAsset).safeTransfer(recipient, fixedFee);
     }
 
     /*//////////////////////////////////////////////////////////////

contracts/PoolFactory.sol

@@ -4,11 +4,13 @@ pragma solidity ^0.8.16;
 import "./Pool.sol";
 import "./interfaces/IServiceConfiguration.sol";
 import "./interfaces/IPoolFactory.sol";
+import {BeaconProxy} from "@openzeppelin/contracts/proxy/beacon/BeaconProxy.sol";
+import "./upgrades/interfaces/IBeacon.sol";
 
 /**
  * @title PoolFactory
  */
-contract PoolFactory is IPoolFactory {
+contract PoolFactory is IPoolFactory, IBeacon {
     /**
      * @dev Reference to the ServiceConfiguration contract
      */
@@ -24,6 +26,22 @@ contract PoolFactory is IPoolFactory {
      */
     address internal _poolControllerFactory;
 
+    /**
+     * @inheritdoc IBeacon
+     */
+    address public implementation;
+
+    /**
+     * @dev Modifier that requires that the sender is registered as a protocol deployer.
+     */
+    modifier onlyDeployer() {
+        require(
+            IServiceConfiguration(_serviceConfiguration).isDeployer(msg.sender),
+            "Upgrade: unauthorized"
+        );
+        _;
+    }
+
     constructor(
         address serviceConfiguration,
         address withdrawControllerFactory,
@@ -34,6 +52,18 @@ contract PoolFactory is IPoolFactory {
         _poolControllerFactory = poolControllerFactory;
     }
 
+    /**
+     * @inheritdoc IBeacon
+     */
+    function setImplementation(address newImplementation)
+        external
+        override
+        onlyDeployer
+    {
+        implementation = newImplementation;
+        emit ImplementationSet(newImplementation);
+    }
+
     /**
      * @dev Creates a pool
      * @dev Emits `PoolCreated` event.
@@ -42,6 +72,10 @@ contract PoolFactory is IPoolFactory {
         address liquidityAsset,
         IPoolConfigurableSettings calldata settings
     ) public virtual returns (address poolAddress) {
+        require(
+            implementation != address(0),
+            "PoolFactory: no implementation set"
+        );
         require(
             IServiceConfiguration(_serviceConfiguration).paused() == false,
             "PoolFactory: Protocol paused"
@@ -95,16 +129,21 @@ contract PoolFactory is IPoolFactory {
         address liquidityAsset,
         IPoolConfigurableSettings calldata settings
     ) internal virtual returns (address) {
-        Pool pool = new Pool(
-            liquidityAsset,
-            msg.sender,
-            _serviceConfiguration,
-            _withdrawControllerFactory,
-            _poolControllerFactory,
-            settings,
-            "PerimeterPoolToken",
-            "PPT"
+        // Create beacon proxy
+        BeaconProxy proxy = new BeaconProxy(
+            address(this),
+            abi.encodeWithSelector(
+                Pool.initialize.selector,
+                liquidityAsset,
+                msg.sender,
+                _serviceConfiguration,
+                _withdrawControllerFactory,
+                _poolControllerFactory,
+                settings,
+                "PerimeterPoolToken",
+                "PPT"
+            )
         );
-        return address(pool);
+        return address(proxy);
     }
 }

contracts/ServiceConfiguration.sol

@@ -1,33 +1,44 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.16;
 
-import "@openzeppelin/contracts/access/AccessControl.sol";
+import "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
 import "./interfaces/IServiceConfiguration.sol";
+import "./upgrades/DeployerUUPSUpgradeable.sol";
+import "hardhat/console.sol";
 
 /**
  * @title The ServiceConfiguration contract
  * @dev Implementation of the {IServiceConfiguration} interface.
  */
-contract ServiceConfiguration is AccessControl, IServiceConfiguration {
+contract ServiceConfiguration is
+    IServiceConfiguration,
+    AccessControlUpgradeable,
+    DeployerUUPSUpgradeable
+{
     /**
      * @dev The Operator Role
      */
     bytes32 public constant OPERATOR_ROLE = keccak256("OPERATOR_ROLE");
 
+    /**
+     * @dev The Operator Role
+     */
+    bytes32 public constant DEPLOYER_ROLE = keccak256("DEPLOYER_ROLE");
+
     /**
      * @dev Whether the protocol is paused.
      */
-    bool public paused = false;
+    bool public paused;
 
     mapping(address => bool) public isLiquidityAsset;
 
     mapping(address => uint256) public firstLossMinimum;
 
-    uint256 public firstLossFeeBps = 500;
+    uint256 public firstLossFeeBps;
 
     address public tosAcceptanceRegistry;
 
-    uint256 public protocolFeeBps = 0;
+    uint256 public protocolFeeBps;
 
     /**
      * @dev Holds a reference to valid LoanFactories
@@ -69,15 +80,6 @@ contract ServiceConfiguration is AccessControl, IServiceConfiguration {
      */
     event TermsOfServiceRegistrySet(address indexed registry);
 
-    /**
-     * @dev Constructor for the contract, which sets up the default roles and
-     * owners.
-     */
-    constructor() {
-        // Grant the contract deployer the Operator role
-        _setupRole(OPERATOR_ROLE, msg.sender);
-    }
-
     /**
      * @dev Modifier that checks that the caller account has the Operator role.
      */
@@ -89,6 +91,19 @@ contract ServiceConfiguration is AccessControl, IServiceConfiguration {
         _;
     }
 
+    /**
+     * @dev Constructor for the contract, which sets up the default roles and
+     * owners.
+     */
+    function initialize() public initializer {
+        // Initialize values
+        paused = false;
+        firstLossFeeBps = 500;
+        protocolFeeBps = 0;
+
+        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
+    }
+
     /**
      * @dev Set a liquidity asset as valid or not.
      */
@@ -116,6 +131,13 @@ contract ServiceConfiguration is AccessControl, IServiceConfiguration {
         return hasRole(OPERATOR_ROLE, addr);
     }
 
+    /**
+     * @inheritdoc IServiceConfiguration
+     */
+    function isDeployer(address addr) external view returns (bool) {
+        return hasRole(DEPLOYER_ROLE, addr);
+    }
+
     /**
      * @inheritdoc IServiceConfiguration
      */
@@ -159,4 +181,11 @@ contract ServiceConfiguration is AccessControl, IServiceConfiguration {
         firstLossFeeBps = value;
         emit ParameterSet("firstLossFeeBps", value);
     }
+
+    /**
+     * @inheritdoc IServiceConfigurable
+     */
+    function serviceConfiguration() external view override returns (address) {
+        return address(this);
+    }
 }

contracts/interfaces/IERC4626.sol

@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.16;
 
-import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {IERC20Upgradeable} from "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
 
 /**
  * @title The interface according to the ERC-4626 standard.
  */
-interface IERC4626 is IERC20 {
+interface IERC4626 is IERC20Upgradeable {
     /**
      * @dev Emitted when tokens are deposited into the vault via the mint and deposit methods.
      */

contracts/interfaces/IServiceConfigurable.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+/**
+ * @title IServiceConfigurable
+ * @dev Interface indicating that the contract is controlled by the protocol service configuration.
+ */
+interface IServiceConfigurable {
+    /**
+     * @dev Address of the protocol service configuration.
+     */
+    function serviceConfiguration() external view returns (address);
+}

contracts/interfaces/IServiceConfiguration.sol

@@ -1,17 +1,20 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity ^0.8.16;
 
-import "@openzeppelin/contracts/access/IAccessControl.sol";
-
 /**
  * @title The protocol global Service Configuration
  */
-interface IServiceConfiguration is IAccessControl {
+interface IServiceConfiguration {
     /**
      * @dev checks if a given address has the Operator role
      */
     function isOperator(address addr) external view returns (bool);
 
+    /**
+     * @dev checks if a given address has the Deployer role
+     */
+    function isDeployer(address addr) external view returns (bool);
+
     function paused() external view returns (bool);
 
     function firstLossMinimum(address addr) external view returns (uint256);

contracts/mocks/upgrades/MockUpgrade.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+abstract contract MockUpgrade {
+    function foo() external pure returns (bool) {
+        return true;
+    }
+}

contracts/mocks/upgrades/PoolMockV2.sol

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+import "../../Pool.sol";
+import "./MockUpgrade.sol";
+
+/**
+ * @dev Simulated new Pool implementation
+ */
+contract PoolMockV2 is Pool, MockUpgrade {
+
+}

contracts/mocks/upgrades/ServiceConfigurationMockV2.sol

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+import "../../ServiceConfiguration.sol";
+import "./MockUpgrade.sol";
+
+/**
+ * @dev Simulated new ServiceConfiguration implementation
+ */
+contract ServiceConfigurationMockV2 is ServiceConfiguration, MockUpgrade {
+
+}