feat(ctb + proposer): Send initial bond when submitting outputs to DGF (

ethereum-optimism#8821) * Add initial bond to `DisputeGameFactory` * Update proposer * fdg semver * fmt * bindings + semver + slither * @refcell nit
ethstorage · Jan 5, 2024 · 19c79fe · 19c79fe
1 parent e496caa
commit 19c79fe
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Showing 13 changed files with 405 additions and 34 deletions.
diff --git a/op-bindings/bindings/disputegamefactory.go b/op-bindings/bindings/disputegamefactory.go
diff --git a/op-bindings/bindings/disputegamefactory_more.go b/op-bindings/bindings/disputegamefactory_more.go
diff --git a/op-bindings/bindings/faultdisputegame.go b/op-bindings/bindings/faultdisputegame.go
diff --git a/op-bindings/bindings/faultdisputegame_more.go b/op-bindings/bindings/faultdisputegame_more.go
diff --git a/op-proposer/proposer/driver.go b/op-proposer/proposer/driver.go
@@ -310,8 +310,16 @@ func proposeL2OutputTxData(abi *abi.ABI, output *eth.OutputResponse) ([]byte, er
 		new(big.Int).SetUint64(output.Status.CurrentL1.Number))
 }
 
-func (l *L2OutputSubmitter) ProposeL2OutputDGFTxData(output *eth.OutputResponse) ([]byte, error) {
-	return proposeL2OutputDGFTxData(l.dgfABI, l.Cfg.DisputeGameType, output)
+func (l *L2OutputSubmitter) ProposeL2OutputDGFTxData(output *eth.OutputResponse) ([]byte, *big.Int, error) {
+	bond, err := l.dgfContract.InitBonds(&bind.CallOpts{}, l.Cfg.DisputeGameType)
+	if err != nil {
+		return nil, nil, err
+	}
+	data, err := proposeL2OutputDGFTxData(l.dgfABI, l.Cfg.DisputeGameType, output)
+	if err != nil {
+		return nil, nil, err
+	}
+	return data, bond, err
 }
 
 // proposeL2OutputDGFTxData creates the transaction data for the DisputeGameFactory's `create` function
@@ -356,14 +364,15 @@ func (l *L2OutputSubmitter) sendTransaction(ctx context.Context, output *eth.Out
 
 	var receipt *types.Receipt
 	if l.Cfg.DisputeGameFactoryAddr != nil {
-		data, err := l.ProposeL2OutputDGFTxData(output)
+		data, bond, err := l.ProposeL2OutputDGFTxData(output)
 		if err != nil {
 			return err
 		}
 		receipt, err = l.Txmgr.Send(ctx, txmgr.TxCandidate{
 			TxData:   data,
 			To:       l.Cfg.DisputeGameFactoryAddr,
 			GasLimit: 0,
+			Value:    bond,
 		})
 		if err != nil {
 			return err

diff --git a/packages/contracts-bedrock/semver-lock.json b/packages/contracts-bedrock/semver-lock.json
@@ -88,12 +88,12 @@
     "sourceCodeHash": "0x1afb1d392e8f6a58ff86ea7f648e0d1756d4ba8d0d964279d58a390deaa53b7e"
   },
   "src/dispute/DisputeGameFactory.sol": {
-    "initCodeHash": "0x79ede9274590494d776c9e2ecdf006cb7106f97490841ea85b52fc8eb18cd7b9",
-    "sourceCodeHash": "0x6e3a697764840cd30ca4b3e514528b832ce80bb412ac958b5ec6b751a07d735f"
+    "initCodeHash": "0xf6ab546550f8d3d85e9bde748eeea21f7fb16db3d63b8312c04598ca64c1be16",
+    "sourceCodeHash": "0x01c757935c87dcf2faa7f16bcf29cfb29b90c671a874f983067614670147b11d"
   },
   "src/dispute/FaultDisputeGame.sol": {
-    "initCodeHash": "0xe3c50aa8ab4ba7a4b4b6d5752a3a3acc2ca0efccbc086df8e00f85d4d696ab15",
-    "sourceCodeHash": "0xbc5e4e6ec9d4438494cacd6ed284456b41a9b6e090fa4b39a59cf122c8c3667d"
+    "initCodeHash": "0x2f30aa96d5c4d126d93dfe15bbfc90e1bbd6bc6208bcc4a49e250790c2a0918d",
+    "sourceCodeHash": "0x315508f5b100dcb6b81077fb8d6999de425b47f0dfd0330ac1973ee4df166f4a"
   },
   "src/legacy/DeployerWhitelist.sol": {
     "initCodeHash": "0x8de80fb23b26dd9d849f6328e56ea7c173cd9e9ce1f05c9beea559d1720deb3d",

diff --git a/packages/contracts-bedrock/slither-report.json b/packages/contracts-bedrock/slither-report.json
@@ -952,7 +952,7 @@
     "impact": "Medium",
     "confidence": "Medium",
     "check": "reentrancy-no-eth",
-    "description": "Reentrancy in FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191):\n\tExternal calls:\n\t- validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw() (src/dispute/FaultDisputeGame.sol#184)\n\tState variables written after the call(s):\n\t- parent.counteredBy = msg.sender (src/dispute/FaultDisputeGame.sol#190)\n\tFaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66) can be used in cross function reentrancies:\n\t- FaultDisputeGame._findStartingAndDisputedOutputs(uint256) (src/dispute/FaultDisputeGame.sol#664-723)\n\t- FaultDisputeGame._findTraceAncestor(Position,uint256,bool) (src/dispute/FaultDisputeGame.sol#637-655)\n\t- FaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66)\n\t- FaultDisputeGame.claimDataLen() (src/dispute/FaultDisputeGame.sol#512-514)\n\t- FaultDisputeGame.initialize() (src/dispute/FaultDisputeGame.sol#454-509)\n\t- FaultDisputeGame.move(uint256,Claim,bool) (src/dispute/FaultDisputeGame.sol#197-288)\n\t- FaultDisputeGame.resolve() (src/dispute/FaultDisputeGame.sol#353-365)\n\t- FaultDisputeGame.resolveClaim(uint256) (src/dispute/FaultDisputeGame.sol#368-428)\n\t- FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191)\n",
+    "description": "Reentrancy in FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191):\n\tExternal calls:\n\t- validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw() (src/dispute/FaultDisputeGame.sol#184)\n\tState variables written after the call(s):\n\t- parent.counteredBy = msg.sender (src/dispute/FaultDisputeGame.sol#190)\n\tFaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66) can be used in cross function reentrancies:\n\t- FaultDisputeGame._findStartingAndDisputedOutputs(uint256) (src/dispute/FaultDisputeGame.sol#662-721)\n\t- FaultDisputeGame._findTraceAncestor(Position,uint256,bool) (src/dispute/FaultDisputeGame.sol#635-653)\n\t- FaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66)\n\t- FaultDisputeGame.claimDataLen() (src/dispute/FaultDisputeGame.sol#510-512)\n\t- FaultDisputeGame.initialize() (src/dispute/FaultDisputeGame.sol#454-507)\n\t- FaultDisputeGame.move(uint256,Claim,bool) (src/dispute/FaultDisputeGame.sol#197-288)\n\t- FaultDisputeGame.resolve() (src/dispute/FaultDisputeGame.sol#353-365)\n\t- FaultDisputeGame.resolveClaim(uint256) (src/dispute/FaultDisputeGame.sol#368-428)\n\t- FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191)\n",
     "type": "function",
     "name": "step",
     "start": 4981,
@@ -964,7 +964,7 @@
     "impact": "Medium",
     "confidence": "Medium",
     "check": "reentrancy-no-eth",
-    "description": "Reentrancy in FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191):\n\tExternal calls:\n\t- validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw() (src/dispute/FaultDisputeGame.sol#184)\n\tState variables written after the call(s):\n\t- parent.counteredBy = msg.sender (src/dispute/FaultDisputeGame.sol#190)\n\tFaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66) can be used in cross function reentrancies:\n\t- FaultDisputeGame._findStartingAndDisputedOutputs(uint256) (src/dispute/FaultDisputeGame.sol#664-723)\n\t- FaultDisputeGame._findTraceAncestor(Position,uint256,bool) (src/dispute/FaultDisputeGame.sol#637-655)\n\t- FaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66)\n\t- FaultDisputeGame.claimDataLen() (src/dispute/FaultDisputeGame.sol#512-514)\n\t- FaultDisputeGame.initialize() (src/dispute/FaultDisputeGame.sol#454-509)\n\t- FaultDisputeGame.move(uint256,Claim,bool) (src/dispute/FaultDisputeGame.sol#197-288)\n\t- FaultDisputeGame.resolve() (src/dispute/FaultDisputeGame.sol#353-365)\n\t- FaultDisputeGame.resolveClaim(uint256) (src/dispute/FaultDisputeGame.sol#368-428)\n\t- FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191)\n",
+    "description": "Reentrancy in FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191):\n\tExternal calls:\n\t- validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw() (src/dispute/FaultDisputeGame.sol#184)\n\tState variables written after the call(s):\n\t- parent.counteredBy = msg.sender (src/dispute/FaultDisputeGame.sol#190)\n\tFaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66) can be used in cross function reentrancies:\n\t- FaultDisputeGame._findStartingAndDisputedOutputs(uint256) (src/dispute/FaultDisputeGame.sol#662-721)\n\t- FaultDisputeGame._findTraceAncestor(Position,uint256,bool) (src/dispute/FaultDisputeGame.sol#635-653)\n\t- FaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66)\n\t- FaultDisputeGame.claimDataLen() (src/dispute/FaultDisputeGame.sol#510-512)\n\t- FaultDisputeGame.initialize() (src/dispute/FaultDisputeGame.sol#454-507)\n\t- FaultDisputeGame.move(uint256,Claim,bool) (src/dispute/FaultDisputeGame.sol#197-288)\n\t- FaultDisputeGame.resolve() (src/dispute/FaultDisputeGame.sol#353-365)\n\t- FaultDisputeGame.resolveClaim(uint256) (src/dispute/FaultDisputeGame.sol#368-428)\n\t- FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191)\n",
     "type": "node",
     "name": "validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw()",
     "start": 8761,
@@ -976,7 +976,7 @@
     "impact": "Medium",
     "confidence": "Medium",
     "check": "reentrancy-no-eth",
-    "description": "Reentrancy in FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191):\n\tExternal calls:\n\t- validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw() (src/dispute/FaultDisputeGame.sol#184)\n\tState variables written after the call(s):\n\t- parent.counteredBy = msg.sender (src/dispute/FaultDisputeGame.sol#190)\n\tFaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66) can be used in cross function reentrancies:\n\t- FaultDisputeGame._findStartingAndDisputedOutputs(uint256) (src/dispute/FaultDisputeGame.sol#664-723)\n\t- FaultDisputeGame._findTraceAncestor(Position,uint256,bool) (src/dispute/FaultDisputeGame.sol#637-655)\n\t- FaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66)\n\t- FaultDisputeGame.claimDataLen() (src/dispute/FaultDisputeGame.sol#512-514)\n\t- FaultDisputeGame.initialize() (src/dispute/FaultDisputeGame.sol#454-509)\n\t- FaultDisputeGame.move(uint256,Claim,bool) (src/dispute/FaultDisputeGame.sol#197-288)\n\t- FaultDisputeGame.resolve() (src/dispute/FaultDisputeGame.sol#353-365)\n\t- FaultDisputeGame.resolveClaim(uint256) (src/dispute/FaultDisputeGame.sol#368-428)\n\t- FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191)\n",
+    "description": "Reentrancy in FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191):\n\tExternal calls:\n\t- validStep = VM.step(_stateData,_proof,uuid.raw()) == postState.claim.raw() (src/dispute/FaultDisputeGame.sol#184)\n\tState variables written after the call(s):\n\t- parent.counteredBy = msg.sender (src/dispute/FaultDisputeGame.sol#190)\n\tFaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66) can be used in cross function reentrancies:\n\t- FaultDisputeGame._findStartingAndDisputedOutputs(uint256) (src/dispute/FaultDisputeGame.sol#662-721)\n\t- FaultDisputeGame._findTraceAncestor(Position,uint256,bool) (src/dispute/FaultDisputeGame.sol#635-653)\n\t- FaultDisputeGame.claimData (src/dispute/FaultDisputeGame.sol#66)\n\t- FaultDisputeGame.claimDataLen() (src/dispute/FaultDisputeGame.sol#510-512)\n\t- FaultDisputeGame.initialize() (src/dispute/FaultDisputeGame.sol#454-507)\n\t- FaultDisputeGame.move(uint256,Claim,bool) (src/dispute/FaultDisputeGame.sol#197-288)\n\t- FaultDisputeGame.resolve() (src/dispute/FaultDisputeGame.sol#353-365)\n\t- FaultDisputeGame.resolveClaim(uint256) (src/dispute/FaultDisputeGame.sol#368-428)\n\t- FaultDisputeGame.step(uint256,bool,bytes,bytes) (src/dispute/FaultDisputeGame.sol#124-191)\n",
     "type": "node",
     "name": "parent.counteredBy = msg.sender",
     "start": 9171,
@@ -1072,10 +1072,10 @@
     "impact": "Medium",
     "confidence": "Medium",
     "check": "uninitialized-local",
-    "description": "FaultDisputeGame._findStartingAndDisputedOutputs(uint256).currentDepth (src/dispute/FaultDisputeGame.sol#682) is a local variable never initialized\n",
+    "description": "FaultDisputeGame._findStartingAndDisputedOutputs(uint256).currentDepth (src/dispute/FaultDisputeGame.sol#680) is a local variable never initialized\n",
     "type": "variable",
     "name": "currentDepth",
-    "start": 32191,
+    "start": 32115,
     "length": 20,
     "filename_relative": "src/dispute/FaultDisputeGame.sol"
   },

diff --git a/packages/contracts-bedrock/snapshots/abi/DisputeGameFactory.json b/packages/contracts-bedrock/snapshots/abi/DisputeGameFactory.json
@@ -157,6 +157,25 @@
     "stateMutability": "pure",
     "type": "function"
   },
+  {
+    "inputs": [
+      {
+        "internalType": "GameType",
+        "name": "",
+        "type": "uint8"
+      }
+    ],
+    "name": "initBonds",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
   {
     "inputs": [
       {
@@ -208,6 +227,24 @@
     "stateMutability": "nonpayable",
     "type": "function"
   },
+  {
+    "inputs": [
+      {
+        "internalType": "GameType",
+        "name": "_gameType",
+        "type": "uint8"
+      },
+      {
+        "internalType": "uint256",
+        "name": "_initBond",
+        "type": "uint256"
+      }
+    ],
+    "name": "setInitBond",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
   {
     "inputs": [
       {
@@ -278,6 +315,25 @@
     "name": "ImplementationSet",
     "type": "event"
   },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "GameType",
+        "name": "gameType",
+        "type": "uint8"
+      },
+      {
+        "indexed": true,
+        "internalType": "uint256",
+        "name": "newBond",
+        "type": "uint256"
+      }
+    ],
+    "name": "InitBondUpdated",
+    "type": "event"
+  },
   {
     "anonymous": false,
     "inputs": [
@@ -321,6 +377,11 @@
     "name": "GameAlreadyExists",
     "type": "error"
   },
+  {
+    "inputs": [],
+    "name": "InsufficientBond",
+    "type": "error"
+  },
   {
     "inputs": [
       {

diff --git a/packages/contracts-bedrock/snapshots/storageLayout/DisputeGameFactory.json b/packages/contracts-bedrock/snapshots/storageLayout/DisputeGameFactory.json
@@ -43,16 +43,23 @@
   },
   {
     "bytes": "32",
-    "label": "_disputeGames",
+    "label": "initBonds",
     "offset": 0,
     "slot": "102",
+    "type": "mapping(GameType => uint256)"
+  },
+  {
+    "bytes": "32",
+    "label": "_disputeGames",
+    "offset": 0,
+    "slot": "103",
     "type": "mapping(Hash => GameId)"
   },
   {
     "bytes": "32",
     "label": "_disputeGameList",
     "offset": 0,
-    "slot": "103",
+    "slot": "104",
     "type": "GameId[]"
   }
 ]
diff --git a/packages/contracts-bedrock/src/dispute/DisputeGameFactory.sol b/packages/contracts-bedrock/src/dispute/DisputeGameFactory.sol
@@ -23,9 +23,16 @@ contract DisputeGameFactory is OwnableUpgradeable, IDisputeGameFactory, ISemver
     /// @dev Allows for the creation of clone proxies with immutable arguments.
     using ClonesWithImmutableArgs for address;
 
+    /// @notice Semantic version.
+    /// @custom:semver 0.0.8
+    string public constant version = "0.0.8";
+
     /// @inheritdoc IDisputeGameFactory
     mapping(GameType => IDisputeGame) public gameImpls;
 
+    /// @inheritdoc IDisputeGameFactory
+    mapping(GameType => uint256) public initBonds;
+
     /// @notice Mapping of a hash of `gameType || rootClaim || extraData` to
     ///         the deployed `IDisputeGame` clone.
     /// @dev Note: `||` denotes concatenation.
@@ -36,10 +43,6 @@ contract DisputeGameFactory is OwnableUpgradeable, IDisputeGameFactory, ISemver
     ///      track dispute games
     GameId[] internal _disputeGameList;
 
-    /// @notice Semantic version.
-    /// @custom:semver 0.0.7
-    string public constant version = "0.0.7";
-
     /// @notice constructs a new DisputeGameFactory contract.
     constructor() OwnableUpgradeable() {
         initialize(address(0));
@@ -96,6 +99,9 @@ contract DisputeGameFactory is OwnableUpgradeable, IDisputeGameFactory, ISemver
         // If there is no implementation to clone for the given `GameType`, revert.
         if (address(impl) == address(0)) revert NoImplementation(_gameType);
 
+        // If the required initialization bond is not met, revert.
+        if (msg.value < initBonds[_gameType]) revert InsufficientBond();
+
         // Clone the implementation contract and initialize it with the given parameters.
         proxy_ = IDisputeGame(address(impl).clone(abi.encodePacked(_rootClaim, _extraData)));
         proxy_.initialize{ value: msg.value }();
@@ -132,4 +138,10 @@ contract DisputeGameFactory is OwnableUpgradeable, IDisputeGameFactory, ISemver
         gameImpls[_gameType] = _impl;
         emit ImplementationSet(address(_impl), _gameType);
     }
+
+    /// @inheritdoc IDisputeGameFactory
+    function setInitBond(GameType _gameType, uint256 _initBond) external onlyOwner {
+        initBonds[_gameType] = _initBond;
+        emit InitBondUpdated(_gameType, _initBond);
+    }
 }
diff --git a/packages/contracts-bedrock/src/dispute/FaultDisputeGame.sol b/packages/contracts-bedrock/src/dispute/FaultDisputeGame.sol
@@ -81,8 +81,8 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, ISemver {
     bool internal initialized;
 
     /// @notice Semantic version.
-    /// @custom:semver 0.0.23
-    string public constant version = "0.0.23";
+    /// @custom:semver 0.0.24
+    string public constant version = "0.0.24";
 
     /// @param _gameType The type ID of the game.
     /// @param _absolutePrestate The absolute prestate of the instruction trace.
@@ -457,6 +457,7 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, ISemver {
         //
         // Implicit assumptions:
         // - The `gameStatus` state variable defaults to 0, which is `GameStatus.IN_PROGRESS`
+        // - The dispute game factory will enforce the required bond to initialize the game.
         //
         // Explicit checks:
         // - The game must not have already been initialized.
@@ -482,9 +483,6 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, ISemver {
             }
         }
 
-        // INVARIANT: The `msg.value` must be sufficient to cover the required bond.
-        if (getRequiredBond(ROOT_POSITION) > msg.value) revert InsufficientBond();
-
         // Set the root claim
         claimData.push(
             ClaimData({

diff --git a/packages/contracts-bedrock/src/dispute/interfaces/IDisputeGameFactory.sol b/packages/contracts-bedrock/src/dispute/interfaces/IDisputeGameFactory.sol
@@ -19,6 +19,11 @@ interface IDisputeGameFactory {
     /// @param gameType The type of the DisputeGame.
     event ImplementationSet(address indexed impl, GameType indexed gameType);
 
+    /// @notice Emitted when a game type's initialization bond is updated
+    /// @param gameType The type of the DisputeGame.
+    /// @param newBond The new bond (in wei) for initializing the game type.
+    event InitBondUpdated(GameType indexed gameType, uint256 indexed newBond);
+
     /// @notice The total number of dispute games created by this factory.
     /// @return gameCount_ The total number of dispute games created by this factory.
     function gameCount() external view returns (uint256 gameCount_);
@@ -60,6 +65,11 @@ interface IDisputeGameFactory {
     ///         Will be cloned on creation of a new dispute game with the given `gameType`.
     function gameImpls(GameType _gameType) external view returns (IDisputeGame impl_);
 
+    /// @notice Returns the required bonds for initializing a dispute game of the given type.
+    /// @param _gameType The type of the dispute game.
+    /// @return bond_ The required bond for initializing a dispute game of the given type.
+    function initBonds(GameType _gameType) external view returns (uint256 bond_);
+
     /// @notice Creates a new DisputeGame proxy contract.
     /// @param _gameType The type of the DisputeGame - used to decide the proxy implementation.
     /// @param _rootClaim The root claim of the DisputeGame.
@@ -80,6 +90,12 @@ interface IDisputeGameFactory {
     /// @param _impl The implementation contract for the given `GameType`.
     function setImplementation(GameType _gameType, IDisputeGame _impl) external;
 
+    /// @notice Sets the bond (in wei) for initializing a game type.
+    /// @dev May only be called by the `owner`.
+    /// @param _gameType The type of the DisputeGame.
+    /// @param _initBond The bond (in wei) for initializing a game type.
+    function setInitBond(GameType _gameType, uint256 _initBond) external;
+
     /// @notice Returns a unique identifier for the given dispute game parameters.
     /// @dev Hashes the concatenation of `gameType . rootClaim . extraData`
     ///      without expanding memory.