feat(ctb): Checked out pre-mcp impl contracts

packages/contracts-bedrock/src/L1/L1CrossDomainMessenger.sol

@@ -12,36 +12,33 @@ import { Constants } from "src/libraries/Constants.sol";
 /// @notice The L1CrossDomainMessenger is a message passing interface between L1 and L2 responsible
 ///         for sending and receiving data on the L1 side. Users are encouraged to use this
 ///         interface instead of interacting with lower-level contracts directly.
-contract L1CrossDomainMessenger is CrossDomainMessenger, ISemver {
-    /// @notice Address of the OptimismPortal. The public getter for this
-    ///         is legacy and will be removed in the future. Use `portal()` instead.
-    /// @custom:network-specific
-    /// @custom:legacy
-    OptimismPortal public PORTAL;
-
-    /// @notice Semantic version.
-    /// @custom:semver 1.7.1
-    string public constant version = "1.7.1";
+contract L1CrossDomainMessenger is CrossDomainMessenger, Semver {
+    /// @notice Address of the OptimismPortal.
+    OptimismPortal public immutable PORTAL;
 
+    /// @custom:semver 1.4.1
     /// @notice Constructs the L1CrossDomainMessenger contract.
-    constructor() CrossDomainMessenger(Predeploys.L2_CROSS_DOMAIN_MESSENGER) {
-        initialize({ _portal: OptimismPortal(payable(0)) });
-    }
-
-    /// @notice Initializes the contract.
     /// @param _portal Address of the OptimismPortal contract on this network.
-    function initialize(OptimismPortal _portal) public reinitializer(Constants.INITIALIZER) {
+    constructor(OptimismPortal _portal)
+        Semver(1, 4, 1)
+        CrossDomainMessenger(Predeploys.L2_CROSS_DOMAIN_MESSENGER)
+    {
         PORTAL = _portal;
-        __CrossDomainMessenger_init();
+        initialize();
     }
 
-    /// @notice Getter for the OptimismPortal address.
-    function portal() external view returns (address) {
-        return address(PORTAL);
+    /// @notice Initializes the contract.
+    function initialize() public initializer {
+        __CrossDomainMessenger_init();
     }
 
     /// @inheritdoc CrossDomainMessenger
-    function _sendMessage(address _to, uint64 _gasLimit, uint256 _value, bytes memory _data) internal override {
+    function _sendMessage(
+        address _to,
+        uint64 _gasLimit,
+        uint256 _value,
+        bytes memory _data
+    ) internal override {
         PORTAL.depositTransaction{ value: _value }(_to, _value, _gasLimit, false, _data);
     }
 

packages/contracts-bedrock/src/L1/L1ERC721Bridge.sol

@@ -13,25 +13,19 @@ import { Constants } from "src/libraries/Constants.sol";
 /// @notice The L1 ERC721 bridge is a contract which works together with the L2 ERC721 bridge to
 ///         make it possible to transfer ERC721 tokens from Ethereum to Optimism. This contract
 ///         acts as an escrow for ERC721 tokens deposited into L2.
-contract L1ERC721Bridge is ERC721Bridge, ISemver {
+contract L1ERC721Bridge is ERC721Bridge, Semver {
     /// @notice Mapping of L1 token to L2 token to ID to boolean, indicating if the given L1 token
     ///         by ID was deposited for a given L2 token.
     mapping(address => mapping(address => mapping(uint256 => bool))) public deposits;
 
-    /// @notice Semantic version.
-    /// @custom:semver 1.4.1
-    string public constant version = "1.4.1";
-
-    /// @notice Constructs the contract.
-    constructor() ERC721Bridge(Predeploys.L2_ERC721_BRIDGE) {
-        initialize({ _messenger: CrossDomainMessenger(address(0)) });
-    }
-
-    /// @notice Initializes the contract.
+    /// @custom:semver 1.1.2
+    /// @notice Constructs the L1ERC721Bridge contract.
     /// @param _messenger   Address of the CrossDomainMessenger on this network.
-    function initialize(CrossDomainMessenger _messenger) public reinitializer(Constants.INITIALIZER) {
-        __ERC721Bridge_init({ _messenger: _messenger });
-    }
+    /// @param _otherBridge Address of the ERC721 bridge on the other network.
+    constructor(address _messenger, address _otherBridge)
+        Semver(1, 1, 2)
+        ERC721Bridge(_messenger, _otherBridge)
+    {}
 
     /// @notice Completes an ERC721 bridge from the other domain and sends the ERC721 token to the
     ///         recipient on this domain.
@@ -50,10 +44,7 @@ contract L1ERC721Bridge is ERC721Bridge, ISemver {
         address _to,
         uint256 _tokenId,
         bytes calldata _extraData
-    )
-        external
-        onlyOtherBridge
-    {
+    ) external onlyOtherBridge {
         require(_localToken != address(this), "L1ERC721Bridge: local token cannot be self");
 
         // Checks that the L1/L2 NFT pair has a token ID that is escrowed in the L1 Bridge.
@@ -83,15 +74,18 @@ contract L1ERC721Bridge is ERC721Bridge, ISemver {
         uint256 _tokenId,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         require(_remoteToken != address(0), "L1ERC721Bridge: remote token cannot be address(0)");
 
         // Construct calldata for _l2Token.finalizeBridgeERC721(_to, _tokenId)
         bytes memory message = abi.encodeWithSelector(
-            L2ERC721Bridge.finalizeBridgeERC721.selector, _remoteToken, _localToken, _from, _to, _tokenId, _extraData
+            L2ERC721Bridge.finalizeBridgeERC721.selector,
+            _remoteToken,
+            _localToken,
+            _from,
+            _to,
+            _tokenId,
+            _extraData
         );
 
         // Lock token into bridge
@@ -99,7 +93,7 @@ contract L1ERC721Bridge is ERC721Bridge, ISemver {
         IERC721(_localToken).transferFrom(_from, address(this), _tokenId);
 
         // Send calldata into L2
-        messenger.sendMessage(OTHER_BRIDGE, message, _minGasLimit);
+        MESSENGER.sendMessage(OTHER_BRIDGE, message, _minGasLimit);
         emit ERC721BridgeInitiated(_localToken, _remoteToken, _from, _to, _tokenId, _extraData);
     }
 }

packages/contracts-bedrock/src/L1/L1StandardBridge.sol

@@ -17,14 +17,19 @@ import { Constants } from "src/libraries/Constants.sol";
 ///         NOTE: this contract is not intended to support all variations of ERC20 tokens. Examples
 ///         of some token types that may not be properly supported by this contract include, but are
 ///         not limited to: tokens with transfer fees, rebasing tokens, and tokens with blocklists.
-contract L1StandardBridge is StandardBridge, ISemver {
+contract L1StandardBridge is StandardBridge, Semver {
     /// @custom:legacy
     /// @notice Emitted whenever a deposit of ETH from L1 into L2 is initiated.
     /// @param from      Address of the depositor.
     /// @param to        Address of the recipient on L2.
     /// @param amount    Amount of ETH deposited.
     /// @param extraData Extra data attached to the deposit.
-    event ETHDepositInitiated(address indexed from, address indexed to, uint256 amount, bytes extraData);
+    event ETHDepositInitiated(
+        address indexed from,
+        address indexed to,
+        uint256 amount,
+        bytes extraData
+    );
 
     /// @custom:legacy
     /// @notice Emitted whenever a withdrawal of ETH from L2 to L1 is finalized.
@@ -32,7 +37,12 @@ contract L1StandardBridge is StandardBridge, ISemver {
     /// @param to        Address of the recipient on L1.
     /// @param amount    Amount of ETH withdrawn.
     /// @param extraData Extra data attached to the withdrawal.
-    event ETHWithdrawalFinalized(address indexed from, address indexed to, uint256 amount, bytes extraData);
+    event ETHWithdrawalFinalized(
+        address indexed from,
+        address indexed to,
+        uint256 amount,
+        bytes extraData
+    );
 
     /// @custom:legacy
     /// @notice Emitted whenever an ERC20 deposit is initiated.
@@ -68,19 +78,13 @@ contract L1StandardBridge is StandardBridge, ISemver {
         bytes extraData
     );
 
-    /// @notice Semantic version.
-    /// @custom:semver 1.4.1
-    string public constant version = "1.4.1";
-
+    /// @custom:semver 1.1.1
     /// @notice Constructs the L1StandardBridge contract.
-    constructor() StandardBridge(StandardBridge(payable(Predeploys.L2_STANDARD_BRIDGE))) {
-        initialize({ _messenger: CrossDomainMessenger(address(0)) });
-    }
-
-    /// @notice Initializer
-    function initialize(CrossDomainMessenger _messenger) public reinitializer(Constants.INITIALIZER) {
-        __StandardBridge_init({ _messenger: _messenger });
-    }
+    /// @param _messenger Address of the L1CrossDomainMessenger.
+    constructor(address payable _messenger)
+        Semver(1, 1, 1)
+        StandardBridge(_messenger, payable(Predeploys.L2_STANDARD_BRIDGE))
+    {}
 
     /// @notice Allows EOAs to bridge ETH by sending directly to the bridge.
     receive() external payable override onlyEOA {
@@ -108,7 +112,11 @@ contract L1StandardBridge is StandardBridge, ISemver {
     /// @param _extraData   Optional data to forward to L2.
     ///                     Data supplied here will not be used to execute any code on L2 and is
     ///                     only emitted as extra data for the convenience of off-chain tooling.
-    function depositETHTo(address _to, uint32 _minGasLimit, bytes calldata _extraData) external payable {
+    function depositETHTo(
+        address _to,
+        uint32 _minGasLimit,
+        bytes calldata _extraData
+    ) external payable {
         _initiateETHDeposit(msg.sender, _to, _minGasLimit, _extraData);
     }
 
@@ -127,12 +135,16 @@ contract L1StandardBridge is StandardBridge, ISemver {
         uint256 _amount,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        external
-        virtual
-        onlyEOA
-    {
-        _initiateERC20Deposit(_l1Token, _l2Token, msg.sender, msg.sender, _amount, _minGasLimit, _extraData);
+    ) external virtual onlyEOA {
+        _initiateERC20Deposit(
+            _l1Token,
+            _l2Token,
+            msg.sender,
+            msg.sender,
+            _amount,
+            _minGasLimit,
+            _extraData
+        );
     }
 
     /// @custom:legacy
@@ -152,11 +164,16 @@ contract L1StandardBridge is StandardBridge, ISemver {
         uint256 _amount,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        external
-        virtual
-    {
-        _initiateERC20Deposit(_l1Token, _l2Token, msg.sender, _to, _amount, _minGasLimit, _extraData);
+    ) external virtual {
+        _initiateERC20Deposit(
+            _l1Token,
+            _l2Token,
+            msg.sender,
+            _to,
+            _amount,
+            _minGasLimit,
+            _extraData
+        );
     }
 
     /// @custom:legacy
@@ -170,10 +187,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes calldata _extraData
-    )
-        external
-        payable
-    {
+    ) external payable {
         finalizeBridgeETH(_from, _to, _amount, _extraData);
     }
 
@@ -192,9 +206,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes calldata _extraData
-    )
-        external
-    {
+    ) external {
         finalizeBridgeERC20(_l1Token, _l2Token, _from, _to, _amount, _extraData);
     }
 
@@ -210,7 +222,12 @@ contract L1StandardBridge is StandardBridge, ISemver {
     /// @param _to          Address of the recipient on L2.
     /// @param _minGasLimit Minimum gas limit for the deposit message on L2.
     /// @param _extraData   Optional data to forward to L2.
-    function _initiateETHDeposit(address _from, address _to, uint32 _minGasLimit, bytes memory _extraData) internal {
+    function _initiateETHDeposit(
+        address _from,
+        address _to,
+        uint32 _minGasLimit,
+        bytes memory _extraData
+    ) internal {
         _initiateBridgeETH(_from, _to, msg.value, _minGasLimit, _extraData);
     }
 
@@ -230,9 +247,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         uint256 _amount,
         uint32 _minGasLimit,
         bytes memory _extraData
-    )
-        internal
-    {
+    ) internal {
         _initiateBridgeERC20(_l1Token, _l2Token, _from, _to, _amount, _minGasLimit, _extraData);
     }
 
@@ -244,10 +259,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         emit ETHDepositInitiated(_from, _to, _amount, _extraData);
         super._emitETHBridgeInitiated(_from, _to, _amount, _extraData);
     }
@@ -260,10 +272,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         emit ETHWithdrawalFinalized(_from, _to, _amount, _extraData);
         super._emitETHBridgeFinalized(_from, _to, _amount, _extraData);
     }
@@ -278,10 +287,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         emit ERC20DepositInitiated(_localToken, _remoteToken, _from, _to, _amount, _extraData);
         super._emitERC20BridgeInitiated(_localToken, _remoteToken, _from, _to, _amount, _extraData);
     }
@@ -296,10 +302,7 @@ contract L1StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         emit ERC20WithdrawalFinalized(_localToken, _remoteToken, _from, _to, _amount, _extraData);
         super._emitERC20BridgeFinalized(_localToken, _remoteToken, _from, _to, _amount, _extraData);
     }

packages/contracts-bedrock/src/L1/ResourceMetering.sol

@@ -76,16 +76,16 @@ abstract contract ResourceMetering is Initializable {
         uint256 blockDiff = block.number - params.prevBlockNum;
 
         ResourceConfig memory config = _resourceConfig();
-        int256 targetResourceLimit =
-            int256(uint256(config.maxResourceLimit)) / int256(uint256(config.elasticityMultiplier));
+        int256 targetResourceLimit = int256(uint256(config.maxResourceLimit)) /
+            int256(uint256(config.elasticityMultiplier));
 
         if (blockDiff > 0) {
             // Handle updating EIP-1559 style gas parameters. We use EIP-1559 to restrict the rate
             // at which deposits can be created and therefore limit the potential for deposits to
             // spam the L2 system. Fee scheme is very similar to EIP-1559 with minor changes.
             int256 gasUsedDelta = int256(uint256(params.prevBoughtGas)) - targetResourceLimit;
-            int256 baseFeeDelta = (int256(uint256(params.prevBaseFee)) * gasUsedDelta)
-                / (targetResourceLimit * int256(uint256(config.baseFeeMaxChangeDenominator)));
+            int256 baseFeeDelta = (int256(uint256(params.prevBaseFee)) * gasUsedDelta) /
+                (targetResourceLimit * int256(uint256(config.baseFeeMaxChangeDenominator)));
 
             // Update base fee by adding the base fee delta and clamp the resulting value between
             // min and max.
@@ -155,6 +155,10 @@ abstract contract ResourceMetering is Initializable {
     ///         child contract.
     // solhint-disable-next-line func-name-mixedcase
     function __ResourceMetering_init() internal onlyInitializing {
-        params = ResourceParams({ prevBaseFee: 1 gwei, prevBoughtGas: 0, prevBlockNum: uint64(block.number) });
+        params = ResourceParams({
+            prevBaseFee: 1 gwei,
+            prevBoughtGas: 0,
+            prevBlockNum: uint64(block.number)
+        });
     }
 }

packages/contracts-bedrock/src/L2/L2ERC721Bridge.sol

@@ -19,20 +19,15 @@ import { Predeploys } from "src/libraries/Predeploys.sol";
 ///         bridge ONLY supports ERC721s originally deployed on Ethereum. Users will need to
 ///         wait for the one-week challenge period to elapse before their Optimism-native NFT
 ///         can be refunded on L2.
-contract L2ERC721Bridge is ERC721Bridge, ISemver {
-    /// @custom:semver 1.4.0
-    string public constant version = "1.4.0";
-
+contract L2ERC721Bridge is ERC721Bridge, Semver {
+    /// @custom:semver 1.1.1
     /// @notice Constructs the L2ERC721Bridge contract.
+    /// @param _messenger   Address of the CrossDomainMessenger on this network.
     /// @param _otherBridge Address of the ERC721 bridge on the other network.
-    constructor(address _otherBridge) ERC721Bridge(_otherBridge) {
-        initialize();
-    }
-
-    /// @notice Initializes the contract.
-    function initialize() public reinitializer(Constants.INITIALIZER) {
-        __ERC721Bridge_init({ _messenger: CrossDomainMessenger(Predeploys.L2_CROSS_DOMAIN_MESSENGER) });
-    }
+    constructor(address _messenger, address _otherBridge)
+        Semver(1, 1, 1)
+        ERC721Bridge(_messenger, _otherBridge)
+    {}
 
     /// @notice Completes an ERC721 bridge from the other domain and sends the ERC721 token to the
     ///         recipient on this domain.
@@ -51,10 +46,7 @@ contract L2ERC721Bridge is ERC721Bridge, ISemver {
         address _to,
         uint256 _tokenId,
         bytes calldata _extraData
-    )
-        external
-        onlyOtherBridge
-    {
+    ) external onlyOtherBridge {
         require(_localToken != address(this), "L2ERC721Bridge: local token cannot be self");
 
         // Note that supportsInterface makes a callback to the _localToken address which is user
@@ -86,10 +78,7 @@ contract L2ERC721Bridge is ERC721Bridge, ISemver {
         uint256 _tokenId,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         require(_remoteToken != address(0), "L2ERC721Bridge: remote token cannot be address(0)");
 
         // Check that the withdrawal is being initiated by the NFT owner
@@ -101,7 +90,10 @@ contract L2ERC721Bridge is ERC721Bridge, ISemver {
         // Construct calldata for l1ERC721Bridge.finalizeBridgeERC721(_to, _tokenId)
         // slither-disable-next-line reentrancy-events
         address remoteToken = IOptimismMintableERC721(_localToken).remoteToken();
-        require(remoteToken == _remoteToken, "L2ERC721Bridge: remote token does not match given value");
+        require(
+            remoteToken == _remoteToken,
+            "L2ERC721Bridge: remote token does not match given value"
+        );
 
         // When a withdrawal is initiated, we burn the withdrawer's NFT to prevent subsequent L2
         // usage
@@ -109,12 +101,18 @@ contract L2ERC721Bridge is ERC721Bridge, ISemver {
         IOptimismMintableERC721(_localToken).burn(_from, _tokenId);
 
         bytes memory message = abi.encodeWithSelector(
-            L1ERC721Bridge.finalizeBridgeERC721.selector, remoteToken, _localToken, _from, _to, _tokenId, _extraData
+            L1ERC721Bridge.finalizeBridgeERC721.selector,
+            remoteToken,
+            _localToken,
+            _from,
+            _to,
+            _tokenId,
+            _extraData
         );
 
         // Send message to L1 bridge
         // slither-disable-next-line reentrancy-events
-        messenger.sendMessage(OTHER_BRIDGE, message, _minGasLimit);
+        MESSENGER.sendMessage(OTHER_BRIDGE, message, _minGasLimit);
 
         // slither-disable-next-line reentrancy-events
         emit ERC721BridgeInitiated(_localToken, remoteToken, _from, _to, _tokenId, _extraData);

packages/contracts-bedrock/src/L2/L2StandardBridge.sol

@@ -17,7 +17,7 @@ import { Constants } from "src/libraries/Constants.sol";
 ///         NOTE: this contract is not intended to support all variations of ERC20 tokens. Examples
 ///         of some token types that may not be properly supported by this contract include, but are
 ///         not limited to: tokens with transfer fees, rebasing tokens, and tokens with blocklists.
-contract L2StandardBridge is StandardBridge, ISemver {
+contract L2StandardBridge is StandardBridge, Semver {
     /// @custom:legacy
     /// @notice Emitted whenever a withdrawal from L2 to L1 is initiated.
     /// @param l1Token   Address of the token on L1.
@@ -52,24 +52,23 @@ contract L2StandardBridge is StandardBridge, ISemver {
         bytes extraData
     );
 
-    /// @custom:semver 1.4.0
-    string public constant version = "1.4.0";
-
+    /// @custom:semver 1.1.1
     /// @notice Constructs the L2StandardBridge contract.
     /// @param _otherBridge Address of the L1StandardBridge.
-    constructor(StandardBridge _otherBridge) StandardBridge(_otherBridge) {
-        initialize();
-    }
-
-    /// @notice Initializer
-    function initialize() public reinitializer(Constants.INITIALIZER) {
-        __StandardBridge_init({ _messenger: CrossDomainMessenger(Predeploys.L2_CROSS_DOMAIN_MESSENGER) });
-    }
+    constructor(address payable _otherBridge)
+        Semver(1, 1, 1)
+        StandardBridge(payable(Predeploys.L2_CROSS_DOMAIN_MESSENGER), _otherBridge)
+    {}
 
     /// @notice Allows EOAs to bridge ETH by sending directly to the bridge.
     receive() external payable override onlyEOA {
         _initiateWithdrawal(
-            Predeploys.LEGACY_ERC20_ETH, msg.sender, msg.sender, msg.value, RECEIVE_DEFAULT_GAS_LIMIT, bytes("")
+            Predeploys.LEGACY_ERC20_ETH,
+            msg.sender,
+            msg.sender,
+            msg.value,
+            RECEIVE_DEFAULT_GAS_LIMIT,
+            bytes("")
         );
     }
 
@@ -86,12 +85,7 @@ contract L2StandardBridge is StandardBridge, ISemver {
         uint256 _amount,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        external
-        payable
-        virtual
-        onlyEOA
-    {
+    ) external payable virtual onlyEOA {
         _initiateWithdrawal(_l2Token, msg.sender, msg.sender, _amount, _minGasLimit, _extraData);
     }
 
@@ -114,11 +108,7 @@ contract L2StandardBridge is StandardBridge, ISemver {
         uint256 _amount,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        external
-        payable
-        virtual
-    {
+    ) external payable virtual {
         _initiateWithdrawal(_l2Token, msg.sender, _to, _amount, _minGasLimit, _extraData);
     }
 
@@ -138,11 +128,7 @@ contract L2StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes calldata _extraData
-    )
-        external
-        payable
-        virtual
-    {
+    ) external payable virtual {
         if (_l1Token == address(0) && _l2Token == Predeploys.LEGACY_ERC20_ETH) {
             finalizeBridgeETH(_from, _to, _amount, _extraData);
         } else {
@@ -172,9 +158,7 @@ contract L2StandardBridge is StandardBridge, ISemver {
         uint256 _amount,
         uint32 _minGasLimit,
         bytes memory _extraData
-    )
-        internal
-    {
+    ) internal {
         if (_l2Token == Predeploys.LEGACY_ERC20_ETH) {
             _initiateBridgeETH(_from, _to, _amount, _minGasLimit, _extraData);
         } else {
@@ -191,11 +175,15 @@ contract L2StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
-        emit WithdrawalInitiated(address(0), Predeploys.LEGACY_ERC20_ETH, _from, _to, _amount, _extraData);
+    ) internal override {
+        emit WithdrawalInitiated(
+            address(0),
+            Predeploys.LEGACY_ERC20_ETH,
+            _from,
+            _to,
+            _amount,
+            _extraData
+        );
         super._emitETHBridgeInitiated(_from, _to, _amount, _extraData);
     }
 
@@ -207,11 +195,15 @@ contract L2StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
-        emit DepositFinalized(address(0), Predeploys.LEGACY_ERC20_ETH, _from, _to, _amount, _extraData);
+    ) internal override {
+        emit DepositFinalized(
+            address(0),
+            Predeploys.LEGACY_ERC20_ETH,
+            _from,
+            _to,
+            _amount,
+            _extraData
+        );
         super._emitETHBridgeFinalized(_from, _to, _amount, _extraData);
     }
 
@@ -225,10 +217,7 @@ contract L2StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         emit WithdrawalInitiated(_remoteToken, _localToken, _from, _to, _amount, _extraData);
         super._emitERC20BridgeInitiated(_localToken, _remoteToken, _from, _to, _amount, _extraData);
     }
@@ -243,10 +232,7 @@ contract L2StandardBridge is StandardBridge, ISemver {
         address _to,
         uint256 _amount,
         bytes memory _extraData
-    )
-        internal
-        override
-    {
+    ) internal override {
         emit DepositFinalized(_remoteToken, _localToken, _from, _to, _amount, _extraData);
         super._emitERC20BridgeFinalized(_localToken, _remoteToken, _from, _to, _amount, _extraData);
     }

packages/contracts-bedrock/src/universal/ERC721Bridge.sol

@@ -7,17 +7,15 @@ import { Initializable } from "@openzeppelin/contracts/proxy/utils/Initializable
 
 /// @title ERC721Bridge
 /// @notice ERC721Bridge is a base contract for the L1 and L2 ERC721 bridges.
-abstract contract ERC721Bridge is Initializable {
+abstract contract ERC721Bridge {
     /// @notice Messenger contract on this domain.
-    /// @custom:network-specific
-    CrossDomainMessenger public messenger;
+    CrossDomainMessenger public immutable MESSENGER;
 
     /// @notice Address of the bridge on the other network.
-    /// @custom:legacy
     address public immutable OTHER_BRIDGE;
 
     /// @notice Reserve extra slots (to a total of 50) in the storage layout for future upgrades.
-    uint256[48] private __gap;
+    uint256[49] private __gap;
 
     /// @notice Emitted when an ERC721 bridge to the other network is initiated.
     /// @param localToken  Address of the token on this domain.
@@ -54,31 +52,31 @@ abstract contract ERC721Bridge is Initializable {
     /// @notice Ensures that the caller is a cross-chain message from the other bridge.
     modifier onlyOtherBridge() {
         require(
-            msg.sender == address(messenger) && messenger.xDomainMessageSender() == OTHER_BRIDGE,
+            msg.sender == address(MESSENGER) && MESSENGER.xDomainMessageSender() == OTHER_BRIDGE,
             "ERC721Bridge: function can only be called from the other bridge"
         );
         _;
     }
 
-    /// @notice Constructs the contract.
+    /// @param _messenger   Address of the CrossDomainMessenger on this network.
     /// @param _otherBridge Address of the ERC721 bridge on the other network.
-    constructor(address _otherBridge) {
+    constructor(address _messenger, address _otherBridge) {
+        require(_messenger != address(0), "ERC721Bridge: messenger cannot be address(0)");
         require(_otherBridge != address(0), "ERC721Bridge: other bridge cannot be address(0)");
-        OTHER_BRIDGE = _otherBridge;
-    }
 
-    // @notice Initializes the contract.
-    /// @param _messenger   Address of the CrossDomainMessenger on this network.
-    function __ERC721Bridge_init(CrossDomainMessenger _messenger) internal onlyInitializing {
-        messenger = _messenger;
+        MESSENGER = CrossDomainMessenger(_messenger);
+        OTHER_BRIDGE = _otherBridge;
     }
 
-    /// @notice Getter for messenger contract.
-    function MESSENGER() external view returns (CrossDomainMessenger) {
-        return messenger;
+    /// @custom:legacy
+    /// @notice Legacy getter for messenger contract.
+    /// @return Messenger contract on this domain.
+    function messenger() external view returns (CrossDomainMessenger) {
+        return MESSENGER;
     }
 
-    /// @notice Getter for other bridge address.
+    /// @custom:legacy
+    /// @notice Legacy getter for other bridge address.
     /// @return Address of the bridge on the other network.
     function otherBridge() external view returns (address) {
         return OTHER_BRIDGE;
@@ -106,9 +104,7 @@ abstract contract ERC721Bridge is Initializable {
         uint256 _tokenId,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        external
-    {
+    ) external {
         // Modifier requiring sender to be EOA. This prevents against a user error that would occur
         // if the sender is a smart contract wallet that has a different address on the remote chain
         // (or doesn't have an address on the remote chain at all). The user would fail to receive
@@ -117,7 +113,15 @@ abstract contract ERC721Bridge is Initializable {
         // care of the user error we want to avoid.
         require(!Address.isContract(msg.sender), "ERC721Bridge: account is not externally owned");
 
-        _initiateBridgeERC721(_localToken, _remoteToken, msg.sender, msg.sender, _tokenId, _minGasLimit, _extraData);
+        _initiateBridgeERC721(
+            _localToken,
+            _remoteToken,
+            msg.sender,
+            msg.sender,
+            _tokenId,
+            _minGasLimit,
+            _extraData
+        );
     }
 
     /// @notice Initiates a bridge of an NFT to some recipient's account on the other chain. Note
@@ -142,12 +146,18 @@ abstract contract ERC721Bridge is Initializable {
         uint256 _tokenId,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        external
-    {
+    ) external {
         require(_to != address(0), "ERC721Bridge: nft recipient cannot be address(0)");
 
-        _initiateBridgeERC721(_localToken, _remoteToken, msg.sender, _to, _tokenId, _minGasLimit, _extraData);
+        _initiateBridgeERC721(
+            _localToken,
+            _remoteToken,
+            msg.sender,
+            _to,
+            _tokenId,
+            _minGasLimit,
+            _extraData
+        );
     }
 
     /// @notice Internal function for initiating a token bridge to the other domain.
@@ -168,7 +178,5 @@ abstract contract ERC721Bridge is Initializable {
         uint256 _tokenId,
         uint32 _minGasLimit,
         bytes calldata _extraData
-    )
-        internal
-        virtual;
+    ) internal virtual;
 }

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

+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { Strings } from "@openzeppelin/contracts/utils/Strings.sol";
+
+/// @title Semver
+/// @notice Semver is a simple contract for managing contract versions.
+contract Semver {
+    /// @notice Contract version number (major).
+    uint256 private immutable MAJOR_VERSION;
+
+    /// @notice Contract version number (minor).
+    uint256 private immutable MINOR_VERSION;
+
+    /// @notice Contract version number (patch).
+    uint256 private immutable PATCH_VERSION;
+
+    /// @param _major Version number (major).
+    /// @param _minor Version number (minor).
+    /// @param _patch Version number (patch).
+    constructor(
+        uint256 _major,
+        uint256 _minor,
+        uint256 _patch
+    ) {
+        MAJOR_VERSION = _major;
+        MINOR_VERSION = _minor;
+        PATCH_VERSION = _patch;
+    }
+
+    /// @notice Returns the full semver contract version.
+    /// @return Semver contract version as a string.
+    function version() public view returns (string memory) {
+        return
+            string(
+                abi.encodePacked(
+                    Strings.toString(MAJOR_VERSION),
+                    ".",
+                    Strings.toString(MINOR_VERSION),
+                    ".",
+                    Strings.toString(PATCH_VERSION)
+                )
+            );
+    }
+}