Merge pull request #7182 from ethereum-optimism/08-09-feat_Add_decimals_to_tokenFactory

feat: configurable decimals to OptimismMintableERC20

packages/contracts-bedrock/.gas-snapshot

@@ -292,7 +292,7 @@ LegacyERC20ETH_Test:test_burn_doesNotExist_reverts() (gas: 10637)
 LegacyERC20ETH_Test:test_crossDomain_succeeds() (gas: 6341)
 LegacyERC20ETH_Test:test_decreaseAllowance_doesNotExist_reverts() (gas: 10724)
 LegacyERC20ETH_Test:test_increaseAllowance_doesNotExist_reverts() (gas: 10690)
-LegacyERC20ETH_Test:test_metadata_succeeds() (gas: 15470)
+LegacyERC20ETH_Test:test_metadata_succeeds() (gas: 15476)
 LegacyERC20ETH_Test:test_mint_doesNotExist_reverts() (gas: 10627)
 LegacyERC20ETH_Test:test_transferFrom_doesNotExist_reverts() (gas: 12957)
 LegacyERC20ETH_Test:test_transfer_doesNotExist_reverts() (gas: 10755)
@@ -426,9 +426,10 @@ OptimismMintableERC721_Test:test_safeMint_succeeds() (gas: 140547)
 OptimismMintableERC721_Test:test_supportsInterfaces_succeeds() (gas: 9005)
 OptimismMintableERC721_Test:test_tokenURI_succeeds() (gas: 163441)
 OptimismMintableTokenFactory_Test:test_bridge_succeeds() (gas: 9760)
-OptimismMintableTokenFactory_Test:test_createStandardL2Token_remoteIsZero_reverts() (gas: 9471)
-OptimismMintableTokenFactory_Test:test_createStandardL2Token_sameTwice_reverts() (gas: 8937393460516769105)
-OptimismMintableTokenFactory_Test:test_createStandardL2Token_succeeds() (gas: 1295838)
+OptimismMintableTokenFactory_Test:test_createStandardL2TokenWithDecimals_succeeds() (gas: 1304000)
+OptimismMintableTokenFactory_Test:test_createStandardL2Token_remoteIsZero_reverts() (gas: 9570)
+OptimismMintableTokenFactory_Test:test_createStandardL2Token_sameTwice_reverts() (gas: 8937393460516769330)
+OptimismMintableTokenFactory_Test:test_createStandardL2Token_succeeds() (gas: 1303990)
 OptimismPortalUpgradeable_Test:test_initialize_cannotInitImpl_reverts() (gas: 11178)
 OptimismPortalUpgradeable_Test:test_initialize_cannotInitProxy_reverts() (gas: 16111)
 OptimismPortalUpgradeable_Test:test_params_initValuesOnProxy_succeeds() (gas: 26781)

packages/contracts-bedrock/semver-lock.json

@@ -24,8 +24,8 @@
   "src/periphery/op-nft/Optimist.sol": "0x38407f766aa9d394403e9da388dd0265b48901789f3e8a28af50014f9f5251d9",
   "src/periphery/op-nft/OptimistAllowlist.sol": "0x53e9a9dfecbae036fd468e8f34c80c7d9c35bd8908c8a6483db44dbc5128ad69",
   "src/periphery/op-nft/OptimistInviter.sol": "0xfdd5b9d45205ef9372ba37f7a6394724695e676d27a47cb154ee6e4148490013",
-  "src/universal/OptimismMintableERC20.sol": "0xa0b4f168802d0f9eca9ddc54347ca66c34ad7aa0fd84b01e0d7e99a9f86f46d6",
-  "src/universal/OptimismMintableERC20Factory.sol": "0xf4beb7fed4defc3e70b2298831bf0024cceaa8f1cf55fd98c00f5998b8ab5589",
+  "src/universal/OptimismMintableERC20.sol": "0x17fe6e955dc7e9e480e57bc62c227206838b204dcb660b8cb8f6f217319a22ba",
+  "src/universal/OptimismMintableERC20Factory.sol": "0xa8b1781116fd296a2630b94e4e18724b64094a70e2e716cb4c5bf5a8dbe32889",
   "src/universal/OptimismMintableERC721.sol": "0x49dc863caf3e002bf0c90b3af3873990fb282771f4c63735fd61a885b7873983",
   "src/universal/OptimismMintableERC721Factory.sol": "0x502438b009bfaf0ab187914662468261f10446fd85d44a79b29cdaef7b4982ba"
 }
\ No newline at end of file

packages/contracts-bedrock/src/legacy/LegacyERC20ETH.sol

@@ -14,7 +14,7 @@ import { OptimismMintableERC20 } from "../universal/OptimismMintableERC20.sol";
 ///         disabled as part of the EVM equivalence upgrade.
 contract LegacyERC20ETH is OptimismMintableERC20 {
     /// @notice Initializes the contract as an Optimism Mintable ERC20.
-    constructor() OptimismMintableERC20(Predeploys.L2_STANDARD_BRIDGE, address(0), "Ether", "ETH") { }
+    constructor() OptimismMintableERC20(Predeploys.L2_STANDARD_BRIDGE, address(0), "Ether", "ETH", 18) { }
 
     /// @notice Returns the ETH balance of the target account. Overrides the base behavior of the
     ///         contract to preserve the invariant that the balance within this contract always

packages/contracts-bedrock/src/universal/OptimismMintableERC20.sol

@@ -19,6 +19,9 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
     /// @notice Address of the StandardBridge on this network.
     address public immutable BRIDGE;
 
+    /// @notice Decimals of the token
+    uint8 private immutable DECIMALS;
+
     /// @notice Emitted whenever tokens are minted for an account.
     /// @param account Address of the account tokens are being minted for.
     /// @param amount  Amount of tokens minted.
@@ -35,7 +38,7 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
         _;
     }
 
-    /// @custom:semver 1.1.0
+    /// @custom:semver 1.2.0
     /// @param _bridge      Address of the L2 standard bridge.
     /// @param _remoteToken Address of the corresponding L1 token.
     /// @param _name        ERC20 name.
@@ -44,13 +47,15 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
         address _bridge,
         address _remoteToken,
         string memory _name,
-        string memory _symbol
+        string memory _symbol,
+        uint8 _decimals
     )
         ERC20(_name, _symbol)
-        Semver(1, 1, 0)
+        Semver(1, 2, 0)
     {
         REMOTE_TOKEN = _remoteToken;
         BRIDGE = _bridge;
+        DECIMALS = _decimals;
     }
 
     /// @notice Allows the StandardBridge on this network to mint tokens.
@@ -120,4 +125,14 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
     function bridge() public view returns (address) {
         return BRIDGE;
     }
+
+    /// @dev Returns the number of decimals used to get its user representation.
+    /// For example, if `decimals` equals `2`, a balance of `505` tokens should
+    /// be displayed to a user as `5.05` (`505 / 10 ** 2`).
+    /// NOTE: This information is only used for _display_ purposes: it in
+    /// no way affects any of the arithmetic of the contract, including
+    /// {IERC20-balanceOf} and {IERC20-transfer}.
+    function decimals() public view override returns (uint8) {
+        return DECIMALS;
+    }
 }

packages/contracts-bedrock/src/universal/OptimismMintableERC20Factory.sol

@@ -30,11 +30,11 @@ contract OptimismMintableERC20Factory is Semver, Initializable {
     /// @param deployer    Address of the account that deployed the token.
     event OptimismMintableERC20Created(address indexed localToken, address indexed remoteToken, address deployer);
 
-    /// @custom:semver 1.3.0
+    /// @custom:semver 1.4.0
     /// @notice The semver MUST be bumped any time that there is a change in
     ///         the OptimismMintableERC20 token contract since this contract
     ///         is responsible for deploying OptimismMintableERC20 contracts.
-    constructor() Semver(1, 3, 0) {
+    constructor() Semver(1, 4, 0) {
         initialize({ _bridge: address(0) });
     }
 
@@ -81,11 +81,30 @@ contract OptimismMintableERC20Factory is Semver, Initializable {
     )
         public
         returns (address)
+    {
+        return createOptimismMintableERC20WithDecimals(_remoteToken, _name, _symbol, 18);
+    }
+
+    /// @notice Creates an instance of the OptimismMintableERC20 contract, with specified decimals.
+    /// @param _remoteToken Address of the token on the remote chain.
+    /// @param _name        ERC20 name.
+    /// @param _symbol      ERC20 symbol.
+    /// @param _decimals    ERC20 decimals
+    /// @return Address of the newly created token.
+    function createOptimismMintableERC20WithDecimals(
+        address _remoteToken,
+        string memory _name,
+        string memory _symbol,
+        uint8 _decimals
+    )
+        public
+        returns (address)
     {
         require(_remoteToken != address(0), "OptimismMintableERC20Factory: must provide remote token address");
 
         bytes32 salt = keccak256(abi.encode(_remoteToken, _name, _symbol));
-        address localToken = address(new OptimismMintableERC20{salt: salt}(bridge, _remoteToken, _name, _symbol));
+        address localToken =
+            address(new OptimismMintableERC20{salt: salt}(bridge, _remoteToken, _name, _symbol, _decimals));
 
         // Emit the old event too for legacy support.
         emit StandardL2TokenCreated(_remoteToken, localToken);

packages/contracts-bedrock/test/OptimismMintableERC20Factory.t.sol

@@ -18,7 +18,9 @@ contract OptimismMintableTokenFactory_Test is Bridge_Initializer {
 
     function test_createStandardL2Token_succeeds() external {
         address remote = address(4);
-        address local = calculateTokenAddress(remote, "Beep", "BOOP");
+
+        // Defaults to 18 decimals
+        address local = calculateTokenAddress(remote, "Beep", "BOOP", 18);
 
         vm.expectEmit(true, true, true, true);
         emit StandardL2TokenCreated(remote, local);
@@ -27,7 +29,26 @@ contract OptimismMintableTokenFactory_Test is Bridge_Initializer {
         emit OptimismMintableERC20Created(local, remote, alice);
 
         vm.prank(alice);
-        L2TokenFactory.createStandardL2Token(remote, "Beep", "BOOP");
+        address addr = L2TokenFactory.createStandardL2Token(remote, "Beep", "BOOP");
+        assertTrue(addr == local);
+        assertTrue(OptimismMintableERC20(local).decimals() == 18);
+    }
+
+    function test_createStandardL2TokenWithDecimals_succeeds() external {
+        address remote = address(4);
+        address local = calculateTokenAddress(remote, "Beep", "BOOP", 6);
+
+        vm.expectEmit(true, true, true, true);
+        emit StandardL2TokenCreated(remote, local);
+
+        vm.expectEmit(true, true, true, true);
+        emit OptimismMintableERC20Created(local, remote, alice);
+
+        vm.prank(alice);
+        address addr = L2TokenFactory.createOptimismMintableERC20WithDecimals(remote, "Beep", "BOOP", 6);
+        assertTrue(addr == local);
+
+        assertTrue(OptimismMintableERC20(local).decimals() == 6);
     }
 
     function test_createStandardL2Token_sameTwice_reverts() external {
@@ -51,13 +72,14 @@ contract OptimismMintableTokenFactory_Test is Bridge_Initializer {
     function calculateTokenAddress(
         address _remote,
         string memory _name,
-        string memory _symbol
+        string memory _symbol,
+        uint8 _decimals
     )
         internal
         view
         returns (address)
     {
-        bytes memory constructorArgs = abi.encode(address(L2Bridge), _remote, _name, _symbol);
+        bytes memory constructorArgs = abi.encode(address(L2Bridge), _remote, _name, _symbol, _decimals);
         bytes memory bytecode = abi.encodePacked(type(OptimismMintableERC20).creationCode, constructorArgs);
         bytes32 salt = keccak256(abi.encode(_remote, _name, _symbol));
         bytes32 hash = keccak256(abi.encodePacked(bytes1(0xff), address(L2TokenFactory), salt, keccak256(bytecode)));

packages/contracts-bedrock/test/StandardBridge.t.sol

@@ -74,7 +74,8 @@ contract StandardBridge_Stateless_Test is CommonTest {
             _bridge: address(0),
             _remoteToken: address(0),
             _name: "Stonks",
-            _symbol: "STONK"
+            _symbol: "STONK",
+            _decimals: 18
         });
 
         erc20 = new ERC20("Altcoin", "ALT");