Merge pull request #6005 from ethereum-optimism/refcell/array/factory

feat(ctb): Append Only Array in DisputeGameFactory

packages/contracts-bedrock/.gas-snapshot

@@ -27,11 +27,11 @@ CrossDomainOwnable_Test:test_onlyOwner_notOwner_reverts() (gas: 10597)
 CrossDomainOwnable_Test:test_onlyOwner_succeeds() (gas: 34883)
 DeployerWhitelist_Test:test_owner_succeeds() (gas: 7582)
 DeployerWhitelist_Test:test_storageSlots_succeeds() (gas: 33395)
-DisputeGameFactory_Test:test_owner_succeeds() (gas: 7582)
-DisputeGameFactory_Test:test_setImplementation_notOwner_reverts() (gas: 11191)
-DisputeGameFactory_Test:test_setImplementation_succeeds() (gas: 38765)
+DisputeGameFactory_Test:test_owner_succeeds() (gas: 7627)
+DisputeGameFactory_Test:test_setImplementation_notOwner_reverts() (gas: 11169)
+DisputeGameFactory_Test:test_setImplementation_succeeds() (gas: 38743)
 DisputeGameFactory_Test:test_transferOwnership_notOwner_reverts() (gas: 10979)
-DisputeGameFactory_Test:test_transferOwnership_succeeds() (gas: 13180)
+DisputeGameFactory_Test:test_transferOwnership_succeeds() (gas: 13225)
 FeeVault_Test:test_constructor_succeeds() (gas: 18185)
 GasBenchMark_L1CrossDomainMessenger:test_sendMessage_benchmark_0() (gas: 352135)
 GasBenchMark_L1CrossDomainMessenger:test_sendMessage_benchmark_1() (gas: 2950342)
@@ -435,4 +435,4 @@ SystemConfig_Setters_TestFail:test_setResourceConfig_notOwner_reverts() (gas: 11
 SystemConfig_Setters_TestFail:test_setResourceConfig_zeroDenominator_reverts() (gas: 13039)
 SystemConfig_Setters_TestFail:test_setUnsafeBlockSigner_notOwner_reverts() (gas: 10616)
 TransferOnionTest:test_constructor_succeeds() (gas: 564855)
-TransferOnionTest:test_unwrap_succeeds() (gas: 724955)
+TransferOnionTest:test_unwrap_succeeds() (gas: 724955)
\ No newline at end of file

packages/contracts-bedrock/.storage-layout

@@ -253,11 +253,12 @@
 ➡ contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory
 =======================
 
-| Name         | Type                                            | Slot | Offset | Bytes | Contract                                                    |
-|--------------|-------------------------------------------------|------|--------|-------|-------------------------------------------------------------|
-| _owner       | address                                         | 0    | 0      | 20    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
-| gameImpls    | mapping(enum GameType => contract IDisputeGame) | 1    | 0      | 32    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
-| disputeGames | mapping(Hash => contract IDisputeGame)          | 2    | 0      | 32    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
+| Name            | Type                                            | Slot | Offset | Bytes | Contract                                                    |
+|-----------------|-------------------------------------------------|------|--------|-------|-------------------------------------------------------------|
+| _owner          | address                                         | 0    | 0      | 20    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
+| gameImpls       | mapping(enum GameType => contract IDisputeGame) | 1    | 0      | 32    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
+| disputeGames    | mapping(Hash => contract IDisputeGame)          | 2    | 0      | 32    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
+| disputeGameList | contract IDisputeGame[]                         | 3    | 0      | 32    | contracts/dispute/DisputeGameFactory.sol:DisputeGameFactory |
 
 =======================
 ➡ contracts/dispute/BondManager.sol:BondManager

packages/contracts-bedrock/contracts/dispute/DisputeGameFactory.sol

@@ -32,6 +32,13 @@ contract DisputeGameFactory is Ownable, IDisputeGameFactory {
      */
     mapping(Hash => IDisputeGame) internal disputeGames;
 
+    /**
+     * @notice An append-only array of disputeGames that have been created.
+     * @dev This accessor is used by offchain game solvers to efficiently
+     *      track dispute games
+     */
+    IDisputeGame[] public disputeGameList;
+
     /**
      * @notice Constructs a new DisputeGameFactory contract.
      * @param _owner The owner of the contract.
@@ -40,6 +47,13 @@ contract DisputeGameFactory is Ownable, IDisputeGameFactory {
         transferOwnership(_owner);
     }
 
+    /**
+     * @inheritdoc IDisputeGameFactory
+     */
+    function gameCount() external view returns (uint256 _gameCount) {
+        _gameCount = disputeGameList.length;
+    }
+
     /**
      * @inheritdoc IDisputeGameFactory
      */
@@ -81,6 +95,7 @@ contract DisputeGameFactory is Ownable, IDisputeGameFactory {
 
         // Store the dispute game in the mapping & emit the `DisputeGameCreated` event.
         disputeGames[uuid] = proxy;
+        disputeGameList.push(proxy);
         emit DisputeGameCreated(address(proxy), gameType, rootClaim);
     }
 

packages/contracts-bedrock/contracts/dispute/interfaces/IDisputeGameFactory.sol

@@ -29,6 +29,12 @@ interface IDisputeGameFactory {
      */
     event ImplementationSet(address indexed impl, GameType indexed gameType);
 
+    /**
+     * @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);
+
     /**
      * @notice `games` queries an internal a mapping that maps the hash of
      *         `gameType ++ rootClaim ++ extraData` to the deployed `DisputeGame` clone.

packages/contracts-bedrock/contracts/test/DisputeGameFactory.t.sol

@@ -48,6 +48,8 @@ contract DisputeGameFactory_Test is Test {
 
         // Ensure that the dispute game was assigned to the `disputeGames` mapping.
         assertEq(address(factory.games(gt, rootClaim, extraData)), address(proxy));
+        assertEq(factory.gameCount(), 1);
+        assertEq(address(factory.disputeGameList(0)), address(proxy));
     }
 
     /**