improve(OVM_SpokePool): Use bridgeERC20To to bridge native L2 tokens if admin decides to support them

contracts/Blast_SpokePool.sol

@@ -128,21 +128,8 @@ contract Blast_SpokePool is Ovm_SpokePool {
         if (l2TokenAddress == USDB || l2TokenAddress == address(wrappedNativeToken)) {
             _claimYield(IERC20Rebasing(l2TokenAddress));
         }
-        // If the token being bridged is WETH then we need to first unwrap it to ETH and then send ETH over the
-        // canonical bridge. On Optimism, this is address 0xDeadDeAddeAddEAddeadDEaDDEAdDeaDDeAD0000.
-        if (l2TokenAddress == address(wrappedNativeToken)) {
-            WETH9Interface(l2TokenAddress).withdraw(amountToReturn); // Unwrap into ETH.
-            l2TokenAddress = l2Eth; // Set the l2TokenAddress to ETH.
-            IL2ERC20Bridge(Lib_PredeployAddresses.L2_STANDARD_BRIDGE).withdrawTo{ value: amountToReturn }(
-                l2TokenAddress, // _l2Token. Address of the L2 token to bridge over.
-                hubPool, // _to. Withdraw, over the bridge, to the l1 pool contract.
-                amountToReturn, // _amount.
-                l1Gas, // _l1Gas. Unused, but included for potential forward compatibility considerations
-                "" // _data. We don't need to send any data for the bridging action.
-            );
-        }
         // If the token is USDB then use the L2BlastBridge
-        else if (l2TokenAddress == USDB) {
+        if (l2TokenAddress == USDB) {
             IL2ERC20Bridge(L2_BLAST_BRIDGE).bridgeERC20To(
                 l2TokenAddress, // _l2Token. Address of the L2 token to bridge over.
                 L1_USDB,
@@ -151,17 +138,6 @@ contract Blast_SpokePool is Ovm_SpokePool {
                 l1Gas,
                 ""
             );
-        } else
-            IL2ERC20Bridge(
-                tokenBridges[l2TokenAddress] == address(0)
-                    ? Lib_PredeployAddresses.L2_STANDARD_BRIDGE
-                    : tokenBridges[l2TokenAddress]
-            ).withdrawTo(
-                    l2TokenAddress, // _l2Token. Address of the L2 token to bridge over.
-                    hubPool, // _to. Withdraw, over the bridge, to the l1 pool contract.
-                    amountToReturn, // _amount.
-                    l1Gas, // _l1Gas. Unused, but included for potential forward compatibility considerations
-                    "" // _data. We don't need to send any data for the bridging action.
-                );
+        } else super._bridgeTokensToHubPool(amountToReturn, l2TokenAddress);
     }
 }

contracts/Optimism_SpokePool.sol

@@ -9,6 +9,12 @@ import "./external/interfaces/CCTPInterfaces.sol";
  * @notice Optimism Spoke pool.
  */
 contract Optimism_SpokePool is Ovm_SpokePool {
+    // Address of custom bridge used to bridge Synthetix-related assets like SNX.
+    address private constant SYNTHETIX_BRIDGE = 0x136b1EC699c62b0606854056f02dC7Bb80482d63;
+
+    // Address of SNX ERC20
+    address private constant SNX = 0x8700dAec35aF8Ff88c16BdF0418774CB3D7599B4;
+
     /// @custom:oz-upgrades-unsafe-allow constructor
     constructor(
         address _wrappedNativeTokenAddress,
@@ -40,4 +46,14 @@ contract Optimism_SpokePool is Ovm_SpokePool {
     ) public initializer {
         __OvmSpokePool_init(_initialDepositId, _crossDomainAdmin, _hubPool, Lib_PredeployAddresses.OVM_ETH);
     }
+
+    function _bridgeTokensToHubPool(uint256 amountToReturn, address l2TokenAddress) internal virtual override {
+        // Handle custom SNX bridge which doesn't conform to the standard bridge interface.
+        if (l2TokenAddress == SNX)
+            SynthetixBridgeToBase(SYNTHETIX_BRIDGE).withdrawTo(
+                hubPool, // _to. Withdraw, over the bridge, to the l1 pool contract.
+                amountToReturn // _amount.
+            );
+        else super._bridgeTokensToHubPool(amountToReturn, l2TokenAddress);
+    }
 }

contracts/Ovm_SpokePool.sol

@@ -37,6 +37,7 @@ interface IL2ERC20Bridge {
  * @notice OVM specific SpokePool. Uses OVM cross-domain-enabled logic to implement admin only access to functions. * Optimism, Base, and Boba each implement this spoke pool and set their chain specific contract addresses for l2Eth and l2Weth.
  */
 contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
+    using SafeERC20 for IERC20;
     // "l1Gas" parameter used in call to bridge tokens from this contract back to L1 via IL2ERC20Bridge. Currently
     // unused by bridge but included for future compatibility.
     uint32 public l1Gas;
@@ -50,18 +51,18 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
     // replaced by the above constant.
     address private __deprecated_messenger;
 
-    // Address of custom bridge used to bridge Synthetix-related assets like SNX.
-    address private constant SYNTHETIX_BRIDGE = 0x136b1EC699c62b0606854056f02dC7Bb80482d63;
-
-    // Address of SNX ERC20
-    address private constant SNX = 0x8700dAec35aF8Ff88c16BdF0418774CB3D7599B4;
-
     // Stores alternative token bridges to use for L2 tokens that don't go over the standard bridge. This is needed
     // to support non-standard ERC20 tokens on Optimism, such as DIA and SNX which both use custom bridges.
     mapping(address => address) public tokenBridges;
 
+    // Stores mapping of L2 tokens to L1 equivalent tokens. If a mapping is defined for a given L2 token, then
+    // the mapped L1 token can be used in _bridgeTokensToHubPool which can then call bridgeERC20To, which
+    // requires specfiying an L1 token.
+    mapping(address => address) public remoteL1Tokens;
+
     event SetL1Gas(uint32 indexed newL1Gas);
     event SetL2TokenBridge(address indexed l2Token, address indexed tokenBridge);
+    event SetRemoteL1Token(address indexed l2Token, address indexed l1Token);
 
     error NotCrossDomainAdmin();
 
@@ -111,6 +112,11 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
         emit SetL1Gas(newl1Gas);
     }
 
+    function setRemoteL1Token(address l2Token, address l1Token) public onlyAdmin nonReentrant {
+        remoteL1Tokens[l2Token] = l1Token;
+        emit SetRemoteL1Token(l2Token, l1Token);
+    }
+
     /**
      * @notice Set bridge contract for L2 token used to withdraw back to L1.
      * @dev If this mapping isn't set for an L2 token, then the standard bridge will be used to bridge this token.
@@ -160,24 +166,43 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
         else if (_isCCTPEnabled() && l2TokenAddress == address(usdcToken)) {
             _transferUsdc(hubPool, amountToReturn);
         }
-        // Handle custom SNX bridge which doesn't conform to the standard bridge interface.
-        else if (l2TokenAddress == SNX)
-            SynthetixBridgeToBase(SYNTHETIX_BRIDGE).withdrawTo(
-                hubPool, // _to. Withdraw, over the bridge, to the l1 pool contract.
-                amountToReturn // _amount.
-            );
-        else
-            IL2ERC20Bridge(
+        // Note we'll default to withdrawTo instead of bridgeERC20To here because we can assume
+        // we'll only bridge back L2 tokens that are "non-native", i.e. they have a canonical L1 token
+        // that maps to this L2. If we wanted to bridge "native L2" tokens we'd need to call
+        // bridgeERC20To and give allowance to the tokenBridge to spend l2Token from this contract. We'd
+        // also need to know the L1 equivalent token address.
+        else {
+            IL2ERC20Bridge tokenBridge = IL2ERC20Bridge(
                 tokenBridges[l2TokenAddress] == address(0)
                     ? Lib_PredeployAddresses.L2_STANDARD_BRIDGE
                     : tokenBridges[l2TokenAddress]
-            ).withdrawTo(
+            );
+            if (remoteL1Tokens[l2TokenAddress] != address(0)) {
+                // If there is a mapping for this L2 token to an L1 token, then use the L1 token address and
+                // call bridgeERC20To.
+                IERC20(l2TokenAddress).safeIncreaseAllowance(address(tokenBridge), amountToReturn);
+                address remoteL1Token = remoteL1Tokens[l2TokenAddress];
+                tokenBridge.bridgeERC20To(
+                    l2TokenAddress, // _l2Token. Address of the L2 token to bridge over.
+                    remoteL1Token, // Remote token to be received on l1 side. If the
+                    // remoteL1Token on the other chain does not recognize the local token as the correct
+                    // pair token, the ERC20 bridge will fail and the tokens will be returned to sender on
+                    // this chain.
+                    hubPool, // _to
+                    amountToReturn, // _amount
+                    l1Gas, // _l1Gas
+                    "" // _data
+                );
+            } else {
+                tokenBridge.withdrawTo(
                     l2TokenAddress, // _l2Token. Address of the L2 token to bridge over.
                     hubPool, // _to. Withdraw, over the bridge, to the l1 pool contract.
                     amountToReturn, // _amount.
                     l1Gas, // _l1Gas. Unused, but included for potential forward compatibility considerations
                     "" // _data. We don't need to send any data for the bridging action.
                 );
+            }
+        }
     }
 
     // Apply OVM-specific transformation to cross domain admin address on L1.
@@ -188,5 +213,5 @@ contract Ovm_SpokePool is SpokePool, CircleCCTPAdapter {
     // Reserve storage slots for future versions of this base contract to add state variables without
     // affecting the storage layout of child contracts. Decrement the size of __gap whenever state variables
     // are added. This is at bottom of contract to make sure its always at the end of storage.
-    uint256[1000] private __gap;
+    uint256[999] private __gap;
 }

contracts/test/MockBedrockStandardBridge.sol

@@ -23,6 +23,8 @@ contract MockBedrockL2StandardBridge is IL2ERC20Bridge {
         uint256 _minGasLimit,
         bytes calldata _extraData
     ) external {
+        // Check that caller has approved this contract to pull funds, mirroring mainnet's behavior
+        IERC20(_localToken).transferFrom(msg.sender, address(this), _amount);
         // do nothing
     }
 }

scripts/checkStorageLayout.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-CONTRACTS=("Arbitrum_SpokePool" "Optimism_SpokePool" "Polygon_SpokePool" "Linea_SpokePool" "ZkSync_SpokePool" "Ethereum_SpokePool" "Base_SpokePool" "Mode_SpokePool")
+CONTRACTS=("Arbitrum_SpokePool" "Optimism_SpokePool" "Polygon_SpokePool" "Linea_SpokePool" "ZkSync_SpokePool" "Ethereum_SpokePool" "Base_SpokePool" "Mode_SpokePool" "Blast_SpokePool")
 if [[ "$1" == "--overwrite" ]]; then
     for CONTRACT in "${CONTRACTS[@]}"; do
         echo "Overwrite flag detected. Creating new storage layout snapshot of the $CONTRACT contract"

storage-layouts/Base_SpokePool.json

@@ -176,9 +176,15 @@
     },
     {
       "contract": "contracts/Base_SpokePool.sol:Base_SpokePool",
-      "label": "__gap",
+      "label": "remoteL1Tokens",
       "offset": 0,
       "slot": "3165"
+    },
+    {
+      "contract": "contracts/Base_SpokePool.sol:Base_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "3166"
     }
   ]
 }

storage-layouts/Blast_SpokePool.json

@@ -0,0 +1,190 @@
+{
+  "storage": [
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "_initialized",
+      "offset": 0,
+      "slot": "0"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "_initializing",
+      "offset": 1,
+      "slot": "0"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "1"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "51"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "_status",
+      "offset": 0,
+      "slot": "101"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "102"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "151"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "_HASHED_NAME",
+      "offset": 0,
+      "slot": "1151"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "_HASHED_VERSION",
+      "offset": 0,
+      "slot": "1152"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "1153"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "crossDomainAdmin",
+      "offset": 0,
+      "slot": "2153"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "hubPool",
+      "offset": 0,
+      "slot": "2154"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "DEPRECATED_wrappedNativeToken",
+      "offset": 0,
+      "slot": "2155"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "DEPRECATED_depositQuoteTimeBuffer",
+      "offset": 20,
+      "slot": "2155"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "numberOfDeposits",
+      "offset": 24,
+      "slot": "2155"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "pausedFills",
+      "offset": 28,
+      "slot": "2155"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "pausedDeposits",
+      "offset": 29,
+      "slot": "2155"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "rootBundles",
+      "offset": 0,
+      "slot": "2156"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "enabledDepositRoutes",
+      "offset": 0,
+      "slot": "2157"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "DEPRECATED_relayFills",
+      "offset": 0,
+      "slot": "2158"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "DEPRECATED_fillCounter",
+      "offset": 0,
+      "slot": "2159"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "DEPRECATED_depositCounter",
+      "offset": 0,
+      "slot": "2160"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "DEPRECATED_refundsRequested",
+      "offset": 0,
+      "slot": "2161"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "fillStatuses",
+      "offset": 0,
+      "slot": "2162"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "2163"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "l1Gas",
+      "offset": 0,
+      "slot": "3162"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "l2Eth",
+      "offset": 4,
+      "slot": "3162"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__deprecated_messenger",
+      "offset": 0,
+      "slot": "3163"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "tokenBridges",
+      "offset": 0,
+      "slot": "3164"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "remoteL1Tokens",
+      "offset": 0,
+      "slot": "3165"
+    },
+    {
+      "contract": "contracts/Blast_SpokePool.sol:Blast_SpokePool",
+      "label": "__gap",
+      "offset": 0,
+      "slot": "3166"
+    }
+  ]
+}