contracts-bedrock: fixup standard bridge

packages/contracts-bedrock/.gas-snapshot

@@ -198,17 +198,17 @@ L1StandardBridge_DepositERC20_TestFail:test_depositERC20_notEoa_reverts() (gas:
 L1StandardBridge_DepositETHTo_Test:test_depositETHTo_succeeds() (gas: 514657)
 L1StandardBridge_DepositETH_Test:test_depositETH_succeeds() (gas: 501874)
 L1StandardBridge_DepositETH_TestFail:test_depositETH_notEoa_reverts() (gas: 40759)
-L1StandardBridge_FinalizeBridgeETH_Test:test_finalizeBridgeETH_succeeds() (gas: 54082)
-L1StandardBridge_FinalizeBridgeETH_TestFail:test_finalizeBridgeETH_incorrectValue_reverts() (gas: 36531)
-L1StandardBridge_FinalizeBridgeETH_TestFail:test_finalizeBridgeETH_sendToMessenger_reverts() (gas: 36718)
-L1StandardBridge_FinalizeBridgeETH_TestFail:test_finalizeBridgeETH_sendToSelf_reverts() (gas: 36603)
-L1StandardBridge_FinalizeERC20Withdrawal_Test:test_finalizeERC20Withdrawal_succeeds() (gas: 498115)
-L1StandardBridge_FinalizeERC20Withdrawal_TestFail:test_finalizeERC20Withdrawal_notMessenger_reverts() (gas: 33432)
+L1StandardBridge_FinalizeBridgeETH_Test:test_finalizeBridgeETH_succeeds() (gas: 54085)
+L1StandardBridge_FinalizeBridgeETH_TestFail:test_finalizeBridgeETH_incorrectValue_reverts() (gas: 36534)
+L1StandardBridge_FinalizeBridgeETH_TestFail:test_finalizeBridgeETH_sendToMessenger_reverts() (gas: 36721)
+L1StandardBridge_FinalizeBridgeETH_TestFail:test_finalizeBridgeETH_sendToSelf_reverts() (gas: 36606)
+L1StandardBridge_FinalizeERC20Withdrawal_Test:test_finalizeERC20Withdrawal_succeeds() (gas: 498117)
+L1StandardBridge_FinalizeERC20Withdrawal_TestFail:test_finalizeERC20Withdrawal_notMessenger_reverts() (gas: 33435)
 L1StandardBridge_FinalizeERC20Withdrawal_TestFail:test_finalizeERC20Withdrawal_notOtherBridge_reverts() (gas: 34084)
-L1StandardBridge_FinalizeETHWithdrawal_Test:test_finalizeETHWithdrawal_succeeds() (gas: 64602)
-L1StandardBridge_Getter_Test:test_getters_succeeds() (gas: 28352)
+L1StandardBridge_FinalizeETHWithdrawal_Test:test_finalizeETHWithdrawal_succeeds() (gas: 64605)
+L1StandardBridge_Getter_Test:test_getters_succeeds() (gas: 28372)
 L1StandardBridge_Initialize_Test:test_initialize_fix_succeeds() (gas: 5258)
-L1StandardBridge_Initialize_Test:test_initialize_succeeds() (gas: 24175)
+L1StandardBridge_Initialize_Test:test_initialize_succeeds() (gas: 24178)
 L1StandardBridge_Receive_Test:test_receive_succeeds() (gas: 615010)
 L2CrossDomainMessenger_Test:test_messageVersion_succeeds() (gas: 8477)
 L2CrossDomainMessenger_Test:test_relayMessage_retry_succeeds() (gas: 163815)
@@ -273,13 +273,13 @@ L2StandardBridge_BridgeERC20_Test:test_bridgeLegacyERC20_succeeds() (gas: 395741
 L2StandardBridge_BridgeERC20_Test:test_withdrawLegacyERC20_succeeds() (gas: 396103)
 L2StandardBridge_BridgeERC20_Test:test_withdraw_notEOA_reverts() (gas: 251807)
 L2StandardBridge_BridgeERC20_Test:test_withdraw_withdrawingERC20_succeeds() (gas: 387750)
-L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_incorrectValue_reverts() (gas: 26112)
-L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_sendToMessenger_reverts() (gas: 26380)
-L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_sendToSelf_reverts() (gas: 26139)
-L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingERC20_succeeds() (gas: 96071)
-L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingETH_succeeds() (gas: 94925)
-L2StandardBridge_FinalizeBridgeETH_Test:test_finalizeBridgeETH_succeeds() (gas: 45508)
-L2StandardBridge_Test:test_initialize_succeeds() (gas: 26296)
+L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_incorrectValue_reverts() (gas: 26126)
+L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_sendToMessenger_reverts() (gas: 26394)
+L2StandardBridge_Bridge_Test:test_finalizeBridgeETH_sendToSelf_reverts() (gas: 26153)
+L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingERC20_succeeds() (gas: 96085)
+L2StandardBridge_Bridge_Test:test_finalizeDeposit_depositingETH_succeeds() (gas: 94939)
+L2StandardBridge_FinalizeBridgeETH_Test:test_finalizeBridgeETH_succeeds() (gas: 45522)
+L2StandardBridge_Test:test_initialize_succeeds() (gas: 26310)
 L2StandardBridge_Test:test_receive_succeeds() (gas: 176756)
 L2StandardBridge_Test:test_withdraw_ether_succeeds() (gas: 142997)
 L2StandardBridge_Test:test_withdraw_insufficientValue_reverts() (gas: 16552)

packages/contracts-bedrock/.storage-layout

@@ -38,7 +38,7 @@
 | spacer_0_2_20 | address                                         | 0    | 2      | 20    | src/L1/L1StandardBridge.sol:L1StandardBridge |
 | spacer_1_0_20 | address                                         | 1    | 0      | 20    | src/L1/L1StandardBridge.sol:L1StandardBridge |
 | deposits      | mapping(address => mapping(address => uint256)) | 2    | 0      | 32    | src/L1/L1StandardBridge.sol:L1StandardBridge |
-| _MESSENGER    | contract CrossDomainMessenger                   | 3    | 0      | 20    | src/L1/L1StandardBridge.sol:L1StandardBridge |
+| MESSENGER     | contract CrossDomainMessenger                   | 3    | 0      | 20    | src/L1/L1StandardBridge.sol:L1StandardBridge |
 | __gap         | uint256[46]                                     | 4    | 0      | 1472  | src/L1/L1StandardBridge.sol:L1StandardBridge |
 
 =======================
@@ -156,7 +156,7 @@
 | spacer_0_2_20 | address                                         | 0    | 2      | 20    | src/L2/L2StandardBridge.sol:L2StandardBridge |
 | spacer_1_0_20 | address                                         | 1    | 0      | 20    | src/L2/L2StandardBridge.sol:L2StandardBridge |
 | deposits      | mapping(address => mapping(address => uint256)) | 2    | 0      | 32    | src/L2/L2StandardBridge.sol:L2StandardBridge |
-| _MESSENGER    | contract CrossDomainMessenger                   | 3    | 0      | 20    | src/L2/L2StandardBridge.sol:L2StandardBridge |
+| MESSENGER     | contract CrossDomainMessenger                   | 3    | 0      | 20    | src/L2/L2StandardBridge.sol:L2StandardBridge |
 | __gap         | uint256[46]                                     | 4    | 0      | 1472  | src/L2/L2StandardBridge.sol:L2StandardBridge |
 
 =======================

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

@@ -232,7 +232,7 @@ contract L1StandardBridge is StandardBridge, Semver {
     /// @notice Retrieves the access of the corresponding L2 bridge contract.
     /// @return Address of the corresponding L2 bridge contract.
     function l2TokenBridge() external view returns (address) {
-        return address(_OTHER_BRIDGE);
+        return address(OTHER_BRIDGE);
     }
 
     /// @notice Internal function for initiating an ETH deposit.

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

@@ -145,7 +145,7 @@ contract L2StandardBridge is StandardBridge, Semver {
     /// @notice Retrieves the access of the corresponding L1 bridge contract.
     /// @return Address of the corresponding L1 bridge contract.
     function l1TokenBridge() external view returns (address) {
-        return address(_OTHER_BRIDGE);
+        return address(OTHER_BRIDGE);
     }
 
     /// @custom:legacy

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

@@ -22,8 +22,10 @@ abstract contract StandardBridge is Initializable {
     /// @notice The L2 gas limit set when eth is depoisited using the receive() function.
     uint32 internal constant RECEIVE_DEFAULT_GAS_LIMIT = 200_000;
 
-    /// @notice Corresponding bridge on the other domain.
-    StandardBridge internal immutable _OTHER_BRIDGE;
+    /// @notice Corresponding bridge on the other domain. This public getter is deprecated
+    ///         and will be removed in the future. Please use `otherBridge` instead.
+    /// @custom:legacy
+    StandardBridge public immutable OTHER_BRIDGE;
 
     /// @custom:legacy
     /// @custom:spacer messenger
@@ -38,8 +40,11 @@ abstract contract StandardBridge is Initializable {
     /// @notice Mapping that stores deposits for a given pair of local and remote tokens.
     mapping(address => mapping(address => uint256)) public deposits;
 
-    /// @notice Messenger contract on this domain.
-    CrossDomainMessenger internal _MESSENGER;
+    /// @notice Messenger contract on this domain. This public getter is deprecated
+    ///         and will be removed in the future. Please use `messenger` instead.
+    /// @custom:legacy
+    /// @custom:network-specific
+    CrossDomainMessenger public MESSENGER;
 
     /// @notice Reserve extra slots (to a total of 50) in the storage layout for future upgrades.
     ///         A gap size of 46 was chosen here, so that the first slot used in a child contract
@@ -116,8 +121,8 @@ abstract contract StandardBridge 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() == address(_OTHER_BRIDGE),
+            msg.sender == address(MESSENGER) &&
+                MESSENGER.xDomainMessageSender() == address(OTHER_BRIDGE),
             "StandardBridge: function can only be called from the other bridge"
         );
         _;
@@ -125,14 +130,14 @@ abstract contract StandardBridge is Initializable {
 
     /// @param _otherBridge Address of the other StandardBridge contract.
     constructor(StandardBridge _otherBridge) {
-        _OTHER_BRIDGE = _otherBridge;
+        OTHER_BRIDGE = _otherBridge;
     }
 
     /// @notice Initializer.
     /// @param _messenger   Address of CrossDomainMessenger on this network.
     // solhint-disable-next-line func-name-mixedcase
     function __StandardBridge_init(CrossDomainMessenger _messenger) internal onlyInitializing {
-        _MESSENGER = _messenger;
+        MESSENGER = _messenger;
     }
 
     /// @notice Allows EOAs to bridge ETH by sending directly to the bridge.
@@ -142,24 +147,12 @@ abstract contract StandardBridge is Initializable {
     /// @notice Getter for messenger contract.
     /// @return Messenger contract on this domain.
     function messenger() external view returns (CrossDomainMessenger) {
-        return _MESSENGER;
-    }
-
-    /// @notice Legacy getter for messenger contract.
-    /// @custom:legacy
-    function MESSENGER() external view returns (CrossDomainMessenger) {
-        return _MESSENGER;
+        return MESSENGER;
     }
 
     /// @notice Getter for the remote domain bridge contract.
     function otherBridge() external view returns (StandardBridge) {
-        return _OTHER_BRIDGE;
-    }
-
-    /// @notice Legacy getter for the remote domain bridge contract.
-    /// @custom:legacy
-    function OTHER_BRIDGE() external view returns (StandardBridge) {
-        return _OTHER_BRIDGE;
+        return OTHER_BRIDGE;
     }
 
     /// @notice Sends ETH to the sender's address on the other chain.
@@ -267,7 +260,7 @@ abstract contract StandardBridge is Initializable {
     ) public payable onlyOtherBridge {
         require(msg.value == _amount, "StandardBridge: amount sent does not match amount required");
         require(_to != address(this), "StandardBridge: cannot send to self");
-        require(_to != address(_MESSENGER), "StandardBridge: cannot send to messenger");
+        require(_to != address(MESSENGER), "StandardBridge: cannot send to messenger");
 
         // Emit the correct events. By default this will be _amount, but child
         // contracts may override this function in order to emit legacy events as well.
@@ -336,8 +329,8 @@ abstract contract StandardBridge is Initializable {
         // contracts may override this function in order to emit legacy events as well.
         _emitETHBridgeInitiated(_from, _to, _amount, _extraData);
 
-        _MESSENGER.sendMessage{ value: _amount }(
-            address(_OTHER_BRIDGE),
+        MESSENGER.sendMessage{ value: _amount }(
+            address(OTHER_BRIDGE),
             abi.encodeWithSelector(
                 this.finalizeBridgeETH.selector,
                 _from,
@@ -383,8 +376,8 @@ abstract contract StandardBridge is Initializable {
         // contracts may override this function in order to emit legacy events as well.
         _emitERC20BridgeInitiated(_localToken, _remoteToken, _from, _to, _amount, _extraData);
 
-        _MESSENGER.sendMessage(
-            address(_OTHER_BRIDGE),
+        MESSENGER.sendMessage(
+            address(OTHER_BRIDGE),
             abi.encodeWithSelector(
                 this.finalizeBridgeERC20.selector,
                 // Because this call will be executed on the remote chain, we reverse the order of