feat: make M Spoke Token Upgradeable [DO NOT MERGE]

.gitmodules

@@ -5,3 +5,7 @@
 [submodule "lib/common"]
 	path = lib/common
 	url = git@github.com:m0-foundation/common.git
+[submodule "lib/openzeppelin-contracts"]
+	path = lib/openzeppelin-contracts
+	url = git@github.com:OpenZeppelin/openzeppelin-contracts.git
+	branch = release-v5.3

script/Deploy.s.sol

@@ -12,15 +12,18 @@ contract Deploy is Script, DeployBase {
 
     function run() external {
         (address deployer_, ) = deriveRememberKey(vm.envString("MNEMONIC"), 0);
+        address migrationAdmin_ = vm.envAddress("MIGRATION_ADMIN");
 
         console2.log("Deployer:", deployer_);
+        console2.log("Migration Admin:", migrationAdmin_);
 
         vm.startBroadcast(deployer_);
 
-        address mToken_ = deploy(_REGISTRAR);
+        (address implementation_, address proxy_) = deploy(_REGISTRAR, migrationAdmin_);
 
         vm.stopBroadcast();
 
-        console2.log("M Token address:", mToken_);
+        console2.log("M Token Implementation address:", implementation_);
+        console2.log("M Token Proxy address:", proxy_);
     }
 }

script/DeployBase.sol

@@ -2,30 +2,50 @@
 
 pragma solidity 0.8.26;
 
+import { ERC1967Proxy } from "../lib/openzeppelin-contracts/contracts/proxy/ERC1967/ERC1967Proxy.sol";
 import { ContractHelper } from "../lib/common/src/libs/ContractHelper.sol";
 
 import { MToken } from "../src/MToken.sol";
 
 contract DeployBase {
     /**
      * @dev    Deploys the M Token contract.
-     * @param  registrar_ The address of the Registrar contract.
-     * @return mToken_    The address of the deployed M Token contract.
+     * @param  registrar_      The address of the Registrar contract.
+     * @param  migrationAdmin_ The address of a migration admin.
+     * @return implementation_ The address of the deployed M Token implementation.
+     * @return proxy_          The address of the deployed M Token proxy.
      */
-    function deploy(address registrar_) public virtual returns (address mToken_) {
-        // M token needs `registrar_` addresses.
-        return address(new MToken(registrar_));
+    function deploy(address registrar_, address migrationAdmin_) public virtual returns (address implementation_, address proxy_) {
+        implementation_ = address(new MToken(registrar_, migrationAdmin_));
+        proxy_ = address(new ERC1967Proxy(implementation_, abi.encodeCall(MToken.initialize, ())));
     }
 
-    function _getExpectedMToken(address deployer_, uint256 deployerNonce_) internal pure returns (address) {
+    function _getExpectedMTokenImplementation(
+        address deployer_,
+        uint256 deployerNonce_
+    ) internal pure returns (address) {
         return ContractHelper.getContractFrom(deployer_, deployerNonce_);
     }
 
-    function getExpectedMToken(address deployer_, uint256 deployerNonce_) public pure virtual returns (address) {
-        return _getExpectedMToken(deployer_, deployerNonce_);
+    function getExpectedMTokenImplementation(
+        address deployer_,
+        uint256 deployerNonce_
+    ) public pure virtual returns (address) {
+        return _getExpectedMTokenImplementation(deployer_, deployerNonce_);
+    }
+
+    function _getExpectedMTokenProxy(address deployer_, uint256 deployerNonce_) internal pure returns (address) {
+        return ContractHelper.getContractFrom(deployer_, deployerNonce_ + 1);
+    }
+
+    function getExpectedMTokenProxy(
+        address deployer_,
+        uint256 deployerNonce_
+    ) public pure virtual returns (address) {
+        return _getExpectedMTokenProxy(deployer_, deployerNonce_);
     }
 
     function getDeployerNonceAfterMTokenDeployment(uint256 deployerNonce_) public pure virtual returns (uint256) {
-        return deployerNonce_ + 1;
+        return deployerNonce_ + 2;
     }
 }

src/MToken.sol

@@ -4,6 +4,7 @@ pragma solidity 0.8.26;
 
 import { ERC20Extended } from "../lib/common/src/ERC20Extended.sol";
 import { UIntMath } from "../lib/common/src/libs/UIntMath.sol";
+import { Migratable } from "../lib/common/src/Migratable.sol";
 
 import { IERC20 } from "../lib/common/src/interfaces/IERC20.sol";
 
@@ -20,7 +21,7 @@ import { ContinuousIndexingMath } from "./libs/ContinuousIndexingMath.sol";
  * @author M^0 Labs
  * @notice ERC20 M Token living on other chains.
  */
-contract MToken is IMToken, ContinuousIndexing, ERC20Extended {
+contract MToken is IMToken, ContinuousIndexing, ERC20Extended, Migratable {
     /* ============ Structs ============ */
 
     /**
@@ -41,6 +42,9 @@ contract MToken is IMToken, ContinuousIndexing, ERC20Extended {
     /// @inheritdoc IMToken
     address public immutable registrar;
 
+    /// @inheritdoc IMToken
+    address public immutable migrationAdmin;
+
     /// @inheritdoc IMToken
     uint240 public totalNonEarningSupply;
 
@@ -62,11 +66,24 @@ contract MToken is IMToken, ContinuousIndexing, ERC20Extended {
 
     /**
      * @notice Constructs the M Token contract.
-     * @param  registrar_ The address of the Registrar contract.
+     * @dev    Sets immutable storage.
+     * @param  registrar_      The address of the Registrar contract.
+     * @param  portal_         The address of the Portal contract.
+     * @param  migrationAdmin_ The address of a migration admin.
      */
-    constructor(address registrar_) ContinuousIndexing() ERC20Extended("M by M^0", "M", 6) {
+    constructor(address registrar_, address portal_, address migrationAdmin_) ContinuousIndexing() ERC20Extended("M by M^0", "M", 6) {
+        _disableInitializers();
+
         if ((registrar = registrar_) == address(0)) revert ZeroRegistrar();
-        if ((portal = RegistrarReader.getPortal(registrar_)) == address(0)) revert ZeroPortal();
+        if ((portal = portal_) == address(0)) revert ZeroPortal();
+        if ((migrationAdmin = migrationAdmin_) == address(0)) revert ZeroMigrationAdmin();
+    }
+
+    /* ============ Initializer ============ */
+
+    /// @inheritdoc IMToken
+    function initialize() external initializer {
+        _initialize();
     }
 
     /* ============ Interactive Functions ============ */
@@ -112,6 +129,15 @@ contract MToken is IMToken, ContinuousIndexing, ERC20Extended {
         _stopEarning(account_);
     }
 
+    /**
+     * @dev   Performs the contract migration by calling `migrator_`.
+     * @param migrator_ The address of a migrator contract.
+     */
+    function migrate(address migrator_) external {
+        if (msg.sender != migrationAdmin) revert UnauthorizedMigration();
+        _migrate(migrator_);
+    }
+
     /* ============ View/Pure Functions ============ */
 
     /// @inheritdoc IMToken
@@ -438,4 +464,10 @@ contract MToken is IMToken, ContinuousIndexing, ERC20Extended {
     function _revertIfNotPortal() internal view {
         if (msg.sender != portal) revert NotPortal();
     }
+
+    /// @inheritdoc Migratable
+    function _getMigrator() internal pure override returns (address migrator_) {
+        // NOTE: in this version only the admin-controlled migration via `migrate()` function is supported
+        return address(0);
+    }
 }

src/abstract/ContinuousIndexing.sol

@@ -2,6 +2,8 @@
 
 pragma solidity 0.8.26;
 
+import { Initializable } from "../../lib/openzeppelin-contracts/contracts/proxy/utils/Initializable.sol";
+
 import { IContinuousIndexing } from "../interfaces/IContinuousIndexing.sol";
 
 import { ContinuousIndexingMath } from "../libs/ContinuousIndexingMath.sol";
@@ -10,7 +12,7 @@ import { ContinuousIndexingMath } from "../libs/ContinuousIndexingMath.sol";
  * @title Abstract Continuous Indexing Contract to handle index updates in inheriting contracts.
  * @author M^0 Labs
  */
-abstract contract ContinuousIndexing is IContinuousIndexing {
+abstract contract ContinuousIndexing is IContinuousIndexing, Initializable {
     /* ============ Variables ============ */
 
     /// @inheritdoc IContinuousIndexing
@@ -19,10 +21,10 @@ abstract contract ContinuousIndexing is IContinuousIndexing {
     /// @inheritdoc IContinuousIndexing
     uint40 public latestUpdateTimestamp;
 
-    /* ============ Constructor ============ */
+    /* ============ Initializer ============ */
 
-    /// @notice Constructs the ContinuousIndexing contract.
-    constructor() {
+    /// @notice Initializes Proxy's storage.
+    function _initialize() internal onlyInitializing {
         latestIndex = ContinuousIndexingMath.EXP_SCALED_ONE;
         latestUpdateTimestamp = uint40(block.timestamp);
     }

src/interfaces/IMToken.sol

@@ -50,12 +50,18 @@ interface IMToken is IContinuousIndexing, IERC20Extended {
     /// @notice Emitted when principal of total supply (earning and non-earning) will overflow a `type(uint112).max`.
     error OverflowsPrincipalOfTotalSupply();
 
+    /// @notice Emitted when the migrate function is called by a account other than the migration admin.
+    error UnauthorizedMigration();
+
     /// @notice Emitted in constructor if the Portal address in the Registrar is 0x0.
     error ZeroPortal();
 
     /// @notice Emitted in constructor if the Registrar address is 0x0.
     error ZeroRegistrar();
 
+    /// @notice Emitted in constructor if Migration Admin is 0x0.
+    error ZeroMigrationAdmin();
+
     /* ============ Interactive Functions ============ */
 
     /**
@@ -102,6 +108,15 @@ interface IMToken is IContinuousIndexing, IERC20Extended {
      */
     function stopEarning(address account) external;
 
+    /// @notice Initializes the Proxy's storage.
+    function initialize() external;
+
+    /**
+     * @notice Performs an arbitrarily defined migration.
+     * @param  migrator The address of a migrator contract.
+     */
+    function migrate(address migrator) external;
+
     /* ============ View/Pure Functions ============ */
 
     /// @notice The address of the M Portal contract.
@@ -110,6 +125,9 @@ interface IMToken is IContinuousIndexing, IERC20Extended {
     /// @notice The address of the Registrar contract.
     function registrar() external view returns (address);
 
+    /// @notice The account that  can call the `migrate(address migrator)` function.
+    function migrationAdmin() external view returns (address migrationAdmin);
+
     /**
      * @notice The principal of an earner M token balance.
      * @param  account The account to get the principal balance of.

test/Deploy.t.sol

@@ -2,31 +2,48 @@
 
 pragma solidity 0.8.26;
 
-import { Test, console2 } from "../lib/forge-std/src/Test.sol";
+import { Test } from "../lib/forge-std/src/Test.sol";
 
 import { IMToken } from "../src/interfaces/IMToken.sol";
+import { IRegistrar } from "../src/interfaces/IRegistrar.sol";
 
 import { DeployBase } from "../script/DeployBase.sol";
 
-import { MockRegistrar } from "./utils/Mocks.sol";
-
 contract Deploy is Test, DeployBase {
-    MockRegistrar internal _registrar;
+    address internal constant _EXPECTED_PROXY = 0x866A2BF4E572CbcF37D5071A7a58503Bfb36be1b;
+    address internal constant _DEPLOYER = 0xF2f1ACbe0BA726fEE8d75f3E32900526874740BB;
 
-    address internal _portal = makeAddr("portal");
+    address internal immutable _MIGRATION_ADMIN = makeAddr("migration admin");
+    address internal immutable _REGISTRAR = makeAddr("registrar");
+    address internal immutable _PORTAL = makeAddr("portal");
 
-    function setUp() external {
-        _registrar = new MockRegistrar();
-        _registrar.setPortal(_portal);
-    }
+    uint64 internal constant _DEPLOYER_PROXY_NONCE = 8;
 
     function test_deploy() external {
-        address mToken_ = deploy(address(_registrar));
-
-        assertEq(mToken_, getExpectedMToken(address(this), 2));
-
-        // MToken assertions
-        assertEq(IMToken(mToken_).portal(), _portal);
-        assertEq(IMToken(mToken_).registrar(), address(_registrar));
+        vm.mockCall(
+            _REGISTRAR,
+            abi.encodeWithSelector(IRegistrar.portal.selector),
+            abi.encode(_PORTAL)
+        );
+
+        // Set nonce to 1 before `_DEPLOYER_PROXY_NONCE` since implementation is deployed before proxy.
+        vm.setNonce(_DEPLOYER, _DEPLOYER_PROXY_NONCE - 1);
+
+        vm.startPrank(_DEPLOYER);
+        (address implementation_, address proxy_) = deploy(_REGISTRAR, _MIGRATION_ADMIN);
+        vm.stopPrank();
+
+        // M Token Implementation assertions
+        assertEq(implementation_, getExpectedMTokenImplementation(_DEPLOYER, 7));
+        assertEq(IMToken(implementation_).migrationAdmin(), _MIGRATION_ADMIN);
+        assertEq(IMToken(implementation_).registrar(), _REGISTRAR);
+        assertEq(IMToken(implementation_).portal(), _PORTAL);
+
+        // M Token Proxy assertions
+        assertEq(proxy_, getExpectedMTokenProxy(_DEPLOYER, 7));
+        assertEq(proxy_, _EXPECTED_PROXY);
+        assertEq(IMToken(proxy_).migrationAdmin(), _MIGRATION_ADMIN);
+        assertEq(IMToken(proxy_).registrar(), _REGISTRAR);
+        assertEq(IMToken(proxy_).portal(), _PORTAL);
     }
 }

test/MToken.t.sol

@@ -4,6 +4,7 @@ pragma solidity 0.8.26;
 
 import { IERC20Extended } from "../lib/common/src/interfaces/IERC20Extended.sol";
 import { UIntMath } from "../lib/common/src/libs/UIntMath.sol";
+import { ERC1967Proxy } from "../lib/openzeppelin-contracts/contracts/proxy/ERC1967/ERC1967Proxy.sol";
 
 import { IContinuousIndexing } from "../src/interfaces/IContinuousIndexing.sol";
 import { IMToken } from "../src/interfaces/IMToken.sol";
@@ -26,20 +27,24 @@ contract MTokenTests is TestUtils {
 
     address internal _portal = makeAddr("portal");
 
+    address internal _migrationAdmin = makeAddr("migrationAdmin");
     address[] internal _accounts = [_alice, _bob, _charlie, _david];
 
     uint256 internal _start = vm.getBlockTimestamp();
 
     uint128 internal _expectedCurrentIndex;
 
     MockRegistrar internal _registrar;
+
+    MTokenHarness internal _implementation;
     MTokenHarness internal _mToken;
 
     function setUp() external {
         _registrar = new MockRegistrar();
         _registrar.setPortal(_portal);
 
-        _mToken = new MTokenHarness(address(_registrar));
+        _implementation = new MTokenHarness(address(_registrar), _migrationAdmin);
+        _mToken = MTokenHarness(address(new ERC1967Proxy(address(_implementation), abi.encodeCall(IMToken.initialize, ()))));
 
         _mToken.setLatestIndex(_expectedCurrentIndex = 1_100000068703);
     }
@@ -55,14 +60,19 @@ contract MTokenTests is TestUtils {
     /* ============ constructor ============ */
     function test_constructor_zeroRegistrar() external {
         vm.expectRevert(IMToken.ZeroRegistrar.selector);
-        new MTokenHarness(address(0));
+        new MTokenHarness(address(0), _migrationAdmin);
+    }
+
+    function test_constructor_zeroMigrationAdmin() external {
+        vm.expectRevert(IMToken.ZeroMigrationAdmin.selector);
+        new MTokenHarness(address(_registrar), address(0));
     }
 
     function test_constructor_zeroPortal() external {
         _registrar.setPortal(address(0));
 
         vm.expectRevert(IMToken.ZeroPortal.selector);
-        new MTokenHarness(address(_registrar));
+        new MTokenHarness(address(_registrar), _migrationAdmin);
     }
 
     /* ============ mint ============ */