Append only array of games

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 allGames() external view returns (IDisputeGame[] memory _disputeGameList) {
+        _disputeGameList = disputeGameList;
+    }
+
     /**
      * @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 retrieves a list of all dispute games created by this factory.
+     * @return _disputeGameList The list of all dispute games created by this factory.
+     */
+    function allGames() external view returns (IDisputeGame[] memory _disputeGameList);
+
     /**
      * @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 +48,9 @@ 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));
+        IDisputeGame[] memory disputeGameList = factory.allGames();
+        assertEq(disputeGameList.length, 1);
+        assertEq(address(disputeGameList[0]), address(proxy));
     }
 
     /**