Execute forks separately

contracts/ForkableBridge.sol

@@ -57,7 +57,7 @@ contract ForkableBridge is
         address to
     ) external onlyAfterForking {
         require(_hardAssetManager == msg.sender, "Not authorized");
-        require(to == children[0] || to == children[1], "Invalid to address");
+        require(to == children[0] || to == children[1], "Invalid to");
         IERC20(token).transfer(to, amount);
     }
 
@@ -79,9 +79,8 @@ contract ForkableBridge is
         if (parentContract != address(0)) {
             // Also check the parent contract for claims if it is set
             return ForkableBridge(parentContract).isClaimed(index);
-        } else {
-            return false;
         }
+        return false;
     }
 
     /**
@@ -116,7 +115,7 @@ contract ForkableBridge is
         bytes calldata metadata,
         address destinationAddress
     ) external onlyParent {
-        require(originNetwork != networkID, "Token is from this network");
+        require(originNetwork != networkID, "wrong Token");
         _issueBridgedTokens(
             originNetwork,
             token,
@@ -127,16 +126,18 @@ contract ForkableBridge is
     }
 
     // @inheritdoc IForkableBridge
-    function splitTokenIntoChildTokens(
+    function splitTokenIntoChildToken(
         address token,
-        uint256 amount
-    ) external onlyAfterForking {
-        BridgeAssetOperations.splitTokenIntoChildTokens(
+        uint256 amount,
+        bool mintSecondChildAsWell
+    ) public onlyAfterForking {
+        BridgeAssetOperations.splitTokenIntoChildToken(
             token,
             amount,
-            wrappedTokenToTokenInfo[token],
             children[0],
-            children[1]
+            // If the second token should not be minted - to safe gas or since its broken - we pass address(0)
+            mintSecondChildAsWell ? children[1] : address(0),
+            wrappedTokenToTokenInfo[token]
         );
     }
 
@@ -171,17 +172,20 @@ contract ForkableBridge is
      * @dev Allows the forkmanager to take out the forkonomic tokens
      * and send them to the children-bridge contracts
      * Notice that forkonomic tokens are special, as they their main contract
-     * is on L1, but they are still forkable tokens as all the tokens from L2.
+     * is on L1, but they are still forkable tokens as all the tokens from
+     * @param useFirstChild boolean indicating for which child the operation should be run
      */
-    function sendForkonomicTokensToChildren()
-        public
-        onlyForkManger
-        onlyAfterForking
-    {
-        BridgeAssetOperations.sendForkonomicTokensToChildren(
+    function sendForkonomicTokensToChild(
+        uint256 amount,
+        bool useFirstChild,
+        bool useChildTokenAllowance
+    ) public onlyForkManger onlyAfterForking {
+        BridgeAssetOperations.sendForkonomicTokensToChild(
             gasTokenAddress,
-            children[0],
-            children[1]
+            amount,
+            useFirstChild ? children[0] : children[1],
+            useFirstChild,
+            useChildTokenAllowance
         );
     }
 

contracts/ForkingManager.sol

@@ -102,38 +102,32 @@ contract ForkingManager is IForkingManager, ForkableStructure {
     /**
      * @dev function that executes a fork proposal
      */
-    function executeFork() external onlyBeforeForking {
+    function executeFork1() external onlyBeforeForking {
         require(
             executionTimeForProposal != 0 &&
                 // solhint-disable-next-line not-rely-on-time
                 executionTimeForProposal <= block.timestamp,
             "ForkingManager: fork not ready"
         );
+
         NewImplementations memory newImplementations = proposedImplementations;
 
         // Create the children of each contract
         NewInstances memory newInstances;
-        (
-            newInstances.forkingManager.one,
-            newInstances.forkingManager.two
-        ) = _createChildren(newImplementations.forkingManagerImplementation);
-        (newInstances.bridge.one, newInstances.bridge.two) = IForkableBridge(
-            bridge
-        ).createChildren(newImplementations.bridgeImplementation);
-        (newInstances.zkEVM.one, newInstances.zkEVM.two) = IForkableZkEVM(zkEVM)
-            .createChildren(newImplementations.zkEVMImplementation);
-        (
-            newInstances.forkonomicToken.one,
-            newInstances.forkonomicToken.two
-        ) = IForkonomicToken(forkonomicToken).createChildren(
-            newImplementations.forkonomicTokenImplementation
+        (newInstances.forkingManager.one, ) = _createChildren(
+            newImplementations.forkingManagerImplementation
         );
-        (
-            newInstances.globalExitRoot.one,
-            newInstances.globalExitRoot.two
-        ) = IForkableGlobalExitRoot(globalExitRoot).createChildren(
-            newImplementations.globalExitRootImplementation
+        (newInstances.bridge.one, ) = IForkableBridge(bridge).createChildren(
+            newImplementations.bridgeImplementation
         );
+        (newInstances.zkEVM.one, ) = IForkableZkEVM(zkEVM).createChildren(
+            newImplementations.zkEVMImplementation
+        );
+        (newInstances.forkonomicToken.one, ) = IForkonomicToken(forkonomicToken)
+            .createChildren(newImplementations.forkonomicTokenImplementation);
+        (newInstances.globalExitRoot.one, ) = IForkableGlobalExitRoot(
+            globalExitRoot
+        ).createChildren(newImplementations.globalExitRootImplementation);
 
         // Initialize the zkEVM contracts
         IPolygonZkEVM.InitializePackedParameters
@@ -175,11 +169,106 @@ contract ForkingManager is IForkingManager, ForkableStructure {
                 IForkableZkEVM(zkEVM).rollupVerifier(),
                 IPolygonZkEVMBridge(newInstances.bridge.one)
             );
-            initializePackedParameters.chainID = ChainIdManager(chainIdManager)
-                .getNextUsableChainId();
-            initializePackedParameters.forkID = newImplementations.forkID > 0
-                ? newImplementations.forkID
-                : IPolygonZkEVM(zkEVM).forkID();
+        }
+
+        // Initialize the tokens
+        IForkonomicToken(newInstances.forkonomicToken.one).initialize(
+            newInstances.forkingManager.one,
+            forkonomicToken,
+            address(this),
+            string.concat(IERC20Metadata(forkonomicToken).name(), "0"),
+            IERC20Metadata(forkonomicToken).symbol()
+        );
+
+        bytes32[DEPOSIT_CONTRACT_TREE_DEPTH]
+            memory depositBranch = IForkableBridge(bridge).getBranch();
+
+        //Initialize the bridge contracts
+        IForkableBridge(newInstances.bridge.one).initialize(
+            newInstances.forkingManager.one,
+            bridge,
+            0, // network identifiers will always be 0 on mainnet and 1 on L2
+            IBasePolygonZkEVMGlobalExitRoot(newInstances.globalExitRoot.one),
+            address(newInstances.zkEVM.one),
+            address(newInstances.forkonomicToken.one),
+            false,
+            IForkableBridge(bridge).getHardAssetManager(),
+            IForkableBridge(bridge).getLastUpdatedDepositCount(),
+            depositBranch
+        );
+
+        //Initialize the forking manager contracts
+        IForkingManager(newInstances.forkingManager.one).initialize(
+            newInstances.zkEVM.one,
+            newInstances.bridge.one,
+            newInstances.forkonomicToken.one,
+            address(this),
+            newInstances.globalExitRoot.one,
+            arbitrationFee,
+            chainIdManager
+        );
+
+        //Initialize the global exit root contracts
+        IForkableGlobalExitRoot(newInstances.globalExitRoot.one).initialize(
+            newInstances.forkingManager.one,
+            globalExitRoot,
+            newInstances.zkEVM.one,
+            newInstances.bridge.one
+        );
+    }
+
+    /**
+     * @dev function that creates the second fork for the fork proposal
+     */
+    function executeFork2() external onlyBeforeCreatingChild2 {
+        require(
+            executionTimeForProposal != 0 &&
+                // solhint-disable-next-line not-rely-on-time
+                executionTimeForProposal <= block.timestamp,
+            "ForkingManager: fork not ready"
+        );
+        NewImplementations memory newImplementations = proposedImplementations;
+
+        // Create the children of each contract
+        NewInstances memory newInstances;
+        (, newInstances.forkingManager.two) = getChildren();
+        (, newInstances.bridge.two) = IForkableBridge(bridge).getChildren();
+        (, newInstances.zkEVM.two) = IForkableZkEVM(zkEVM).getChildren();
+        (, newInstances.forkonomicToken.two) = IForkonomicToken(forkonomicToken)
+            .getChildren();
+        (, newInstances.globalExitRoot.two) = IForkableGlobalExitRoot(
+            globalExitRoot
+        ).getChildren();
+
+        // Initialize the zkEVM contracts
+        IPolygonZkEVM.InitializePackedParameters
+            memory initializePackedParameters;
+
+        {
+            // retrieve some information from the zkEVM contract
+            bytes32 genesisRoot = IPolygonZkEVM(zkEVM).batchNumToStateRoot(
+                IPolygonZkEVM(zkEVM).lastVerifiedBatch()
+            );
+            // the following variables could be used to save gas, but it requires via-ir in the compiler settings
+            string memory trustedSequencerURL = IPolygonZkEVM(zkEVM)
+                .trustedSequencerURL();
+            string memory networkName = IPolygonZkEVM(zkEVM).networkName();
+            // string memory version = "0.1.0"; // Todo: get version from zkEVM, currently only emitted as event
+            initializePackedParameters = IPolygonZkEVM
+                .InitializePackedParameters({
+                    admin: IPolygonZkEVM(zkEVM).admin(),
+                    trustedSequencer: IPolygonZkEVM(zkEVM).trustedSequencer(),
+                    pendingStateTimeout: IPolygonZkEVM(zkEVM)
+                        .pendingStateTimeout(),
+                    trustedAggregator: IPolygonZkEVM(zkEVM).trustedAggregator(),
+                    trustedAggregatorTimeout: IPolygonZkEVM(zkEVM)
+                        .trustedAggregatorTimeout(),
+                    chainID: ChainIdManager(chainIdManager)
+                        .getNextUsableChainId(),
+                    forkID: newImplementations.forkID > 0
+                        ? newImplementations.forkID
+                        : IPolygonZkEVM(zkEVM).forkID()
+                });
             IForkableZkEVM(newInstances.zkEVM.two).initialize(
                 newInstances.forkingManager.two,
                 zkEVM,
@@ -196,13 +285,6 @@ contract ForkingManager is IForkingManager, ForkableStructure {
         }
 
         // Initialize the tokens
-        IForkonomicToken(newInstances.forkonomicToken.one).initialize(
-            newInstances.forkingManager.one,
-            forkonomicToken,
-            address(this),
-            string.concat(IERC20Metadata(forkonomicToken).name(), "0"),
-            IERC20Metadata(forkonomicToken).symbol()
-        );
         IForkonomicToken(newInstances.forkonomicToken.two).initialize(
             newInstances.forkingManager.two,
             forkonomicToken,
@@ -215,18 +297,6 @@ contract ForkingManager is IForkingManager, ForkableStructure {
             memory depositBranch = IForkableBridge(bridge).getBranch();
 
         //Initialize the bridge contracts
-        IForkableBridge(newInstances.bridge.one).initialize(
-            newInstances.forkingManager.one,
-            bridge,
-            0, // network identifiers will always be 0 on mainnet and 1 on L2
-            IBasePolygonZkEVMGlobalExitRoot(newInstances.globalExitRoot.one),
-            address(newInstances.zkEVM.one),
-            address(newInstances.forkonomicToken.one),
-            false,
-            IForkableBridge(bridge).getHardAssetManager(),
-            IForkableBridge(bridge).getLastUpdatedDepositCount(),
-            depositBranch
-        );
         IForkableBridge(newInstances.bridge.two).initialize(
             newInstances.forkingManager.two,
             bridge,
@@ -241,15 +311,6 @@ contract ForkingManager is IForkingManager, ForkableStructure {
         );
 
         //Initialize the forking manager contracts
-        IForkingManager(newInstances.forkingManager.one).initialize(
-            newInstances.zkEVM.one,
-            newInstances.bridge.one,
-            newInstances.forkonomicToken.one,
-            address(this),
-            newInstances.globalExitRoot.one,
-            arbitrationFee,
-            chainIdManager
-        );
         IForkingManager(newInstances.forkingManager.two).initialize(
             newInstances.zkEVM.two,
             newInstances.bridge.two,
@@ -261,12 +322,6 @@ contract ForkingManager is IForkingManager, ForkableStructure {
         );
 
         //Initialize the global exit root contracts
-        IForkableGlobalExitRoot(newInstances.globalExitRoot.one).initialize(
-            newInstances.forkingManager.one,
-            globalExitRoot,
-            newInstances.zkEVM.one,
-            newInstances.bridge.one
-        );
         IForkableGlobalExitRoot(newInstances.globalExitRoot.two).initialize(
             newInstances.forkingManager.two,
             globalExitRoot,

contracts/ForkonomicToken.sol

@@ -16,6 +16,12 @@ contract ForkonomicToken is
     /// @dev The role that allows minting new tokens
     bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
 
+    /// @dev Mapping that stores burned amounts
+    /// address The address of the token owner
+    /// bool indicating whether the first or second child was burnt
+    /// uint256 The amount of burned tokens
+    mapping(address => mapping(bool => uint256)) public childTokenAllowances;
+
     /// @inheritdoc IForkonomicToken
     function initialize(
         address _forkmanager,
@@ -46,12 +52,42 @@ contract ForkonomicToken is
         return _createChildren(implementation);
     }
 
+    function splitTokenAndMintOneChild(
+        uint256 amount,
+        bool firstChild,
+        bool useChildTokenAllowance
+    ) public onlyAfterForking {
+        require(children[0] != address(0), "Children not created yet");
+        if (useChildTokenAllowance) {
+            require(
+                childTokenAllowances[msg.sender][firstChild] >= amount,
+                "Not enough allowance"
+            );
+            childTokenAllowances[msg.sender][firstChild] -= amount;
+        } else {
+            _burn(msg.sender, amount);
+            childTokenAllowances[msg.sender][!firstChild] += amount;
+        }
+        IForkonomicToken(firstChild ? children[0] : children[1]).mint(
+            msg.sender,
+            amount
+        );
+    }
+
+    /// @dev Allows anyone to prepare the splitting of tokens
+    /// by burning them
+    /// @param amount The amount of tokens to burn
+    function prepareSplittingTokens(uint256 amount) public {
+        require(children[0] != address(0), "Children not created yet");
+        _burn(msg.sender, amount);
+        childTokenAllowances[msg.sender][false] += amount;
+        childTokenAllowances[msg.sender][true] += amount;
+    }
+
     /// @dev Allows anyone to split the tokens from the parent contract into the tokens of the children
     /// @param amount The amount of tokens to split
     function splitTokensIntoChildTokens(uint256 amount) external {
-        require(children[0] != address(0), "Children not created yet");
-        _burn(msg.sender, amount);
-        IForkonomicToken(children[0]).mint(msg.sender, amount);
-        IForkonomicToken(children[1]).mint(msg.sender, amount);
+        splitTokenAndMintOneChild(amount, true, false);
+        splitTokenAndMintOneChild(amount, false, true);
     }
 }

contracts/interfaces/IForkableBridge.sol

@@ -4,8 +4,9 @@ pragma solidity ^0.8.20;
 import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import {IPolygonZkEVMBridge} from "@RealityETH/zkevm-contracts/contracts/interfaces/IPolygonZkEVMBridge.sol";
 import {IBasePolygonZkEVMGlobalExitRoot} from "@RealityETH/zkevm-contracts/contracts/interfaces/IBasePolygonZkEVMGlobalExitRoot.sol";
+import {IForkableStructure} from "./IForkableStructure.sol";
 
-interface IForkableBridge is IPolygonZkEVMBridge {
+interface IForkableBridge is IForkableStructure, IPolygonZkEVMBridge {
     /**
      * @dev Function to initialize the contract
      * @param _forkmanager: address of the forkmanager contract
@@ -49,7 +50,11 @@ interface IForkableBridge is IPolygonZkEVMBridge {
      * @param token token that should be split
      * @param amount amount of tokens to be split
      */
-    function splitTokenIntoChildTokens(address token, uint256 amount) external;
+    function splitTokenIntoChildToken(
+        address token,
+        uint256 amount,
+        bool mintSecondChild
+    ) external;
 
     /**
      * @dev Function to mint the forkable token by the parent contract