Merge pull request #61 from Polymarket/fix/stuck-reward-tokens

Fix: H01

.gas-snapshot

@@ -9,49 +9,52 @@ BulletinBoardTest:testGetLatestUpdate() (gas: 88406)
 BulletinBoardTest:testGetUpdate() (gas: 87904)
 BulletinBoardTest:testPostUpdate() (gas: 83918)
 BulletinBoardTest:testPostUpdateMultiple() (gas: 142834)
-UmaCtfAdapterTest:testEmergencyResolve() (gas: 674039)
-UmaCtfAdapterTest:testEmergencyResolvePaused() (gas: 669958)
-UmaCtfAdapterTest:testEmergencyResolveRevertInvalidPayouts() (gas: 597594)
-UmaCtfAdapterTest:testEmergencyResolveRevertNotAdmin() (gas: 600990)
-UmaCtfAdapterTest:testEmergencyResolveRevertNotFlagged() (gas: 574689)
+UmaCtfAdapterTest:testEmergencyResolve() (gas: 674897)
+UmaCtfAdapterTest:testEmergencyResolvePaused() (gas: 670573)
+UmaCtfAdapterTest:testEmergencyResolveRevertInvalidPayouts() (gas: 597973)
+UmaCtfAdapterTest:testEmergencyResolveRevertNotAdmin() (gas: 601367)
+UmaCtfAdapterTest:testEmergencyResolveRevertNotFlagged() (gas: 575001)
 UmaCtfAdapterTest:testEmergencyResolveRevertNotInitialized() (gas: 18313)
-UmaCtfAdapterTest:testEmergencyResolveRevertSafetyPeriod() (gas: 597849)
-UmaCtfAdapterTest:testExpectedPayouts() (gas: 708827)
-UmaCtfAdapterTest:testExpectedPayoutsRevertIgnorePriceReceived() (gas: 1202332)
-UmaCtfAdapterTest:testExpectedPayoutsRevertNotInitialized() (gas: 13300)
-UmaCtfAdapterTest:testExpectedPayoutsRevertPriceNotAvailable() (gas: 575538)
-UmaCtfAdapterTest:testFlag() (gas: 601560)
-UmaCtfAdapterTest:testFlagRevertNotAdmin() (gas: 574852)
+UmaCtfAdapterTest:testEmergencyResolveRevertSafetyPeriod() (gas: 598226)
+UmaCtfAdapterTest:testEmergencyResolveWhenRefundExists() (gas: 1191277)
+UmaCtfAdapterTest:testExpectedPayouts() (gas: 709449)
+UmaCtfAdapterTest:testExpectedPayoutsRevertIgnorePriceReceived() (gas: 1203605)
+UmaCtfAdapterTest:testExpectedPayoutsRevertNotInitialized() (gas: 13343)
+UmaCtfAdapterTest:testExpectedPayoutsRevertPriceNotAvailable() (gas: 575872)
+UmaCtfAdapterTest:testFlag() (gas: 601916)
+UmaCtfAdapterTest:testFlagRevertNotAdmin() (gas: 575208)
 UmaCtfAdapterTest:testFlagRevertNotInitialized() (gas: 17492)
-UmaCtfAdapterTest:testInitialize() (gas: 641835)
-UmaCtfAdapterTest:testInitializeCustomLiveness() (gas: 549484)
-UmaCtfAdapterTest:testInitializeRevertCustomLiveness() (gas: 450507)
-UmaCtfAdapterTest:testInitializeRevertInsufficientRewardBalance() (gas: 312973)
-UmaCtfAdapterTest:testInitializeRevertInvalidAncillaryData() (gas: 20703)
-UmaCtfAdapterTest:testInitializeRevertOnSameQuestion() (gas: 435398)
-UmaCtfAdapterTest:testInitializeRevertUnsupportedRewardToken() (gas: 854143)
-UmaCtfAdapterTest:testInitializeZeroRewardAndBond() (gas: 494815)
-UmaCtfAdapterTest:testPause() (gas: 590533)
-UmaCtfAdapterTest:testPauseRevertNotAdmin() (gas: 583918)
-UmaCtfAdapterTest:testPauseRevertNotInitialized() (gas: 17523)
-UmaCtfAdapterTest:testPriceDisputed() (gas: 945593)
-UmaCtfAdapterTest:testPriceDisputedAlreadyReset() (gas: 1216563)
-UmaCtfAdapterTest:testPriceDisputedIgnorePriceReceived() (gas: 1373772)
-UmaCtfAdapterTest:testPriceDisputedResolveAfterDispute() (gas: 1149312)
-UmaCtfAdapterTest:testPriceDisputedRevertNotOO() (gas: 11901)
-UmaCtfAdapterTest:testProposed() (gas: 681763)
-UmaCtfAdapterTest:testReady() (gas: 779898)
-UmaCtfAdapterTest:testReset() (gas: 755607)
-UmaCtfAdapterTest:testResetAlreadyReset() (gas: 938667)
+UmaCtfAdapterTest:testInitialize() (gas: 642410)
+UmaCtfAdapterTest:testInitializeCustomLiveness() (gas: 550060)
+UmaCtfAdapterTest:testInitializeRevertCustomLiveness() (gas: 450885)
+UmaCtfAdapterTest:testInitializeRevertInsufficientRewardBalance() (gas: 313330)
+UmaCtfAdapterTest:testInitializeRevertInvalidAncillaryData() (gas: 20681)
+UmaCtfAdapterTest:testInitializeRevertOnSameQuestion() (gas: 435754)
+UmaCtfAdapterTest:testInitializeRevertUnsupportedRewardToken() (gas: 854099)
+UmaCtfAdapterTest:testInitializeZeroRewardAndBond() (gas: 495389)
+UmaCtfAdapterTest:testPause() (gas: 591326)
+UmaCtfAdapterTest:testPauseRevertNotAdmin() (gas: 584275)
+UmaCtfAdapterTest:testPauseRevertNotInitialized() (gas: 17502)
+UmaCtfAdapterTest:testPriceDisputed() (gas: 946424)
+UmaCtfAdapterTest:testPriceDisputedDvmRespondsIgnore() (gas: 1375613)
+UmaCtfAdapterTest:testPriceDisputedDvmRespondsNo() (gas: 1213524)
+UmaCtfAdapterTest:testPriceDisputedDvmRespondsYes() (gas: 1253323)
+UmaCtfAdapterTest:testPriceDisputedResolveAfterDispute() (gas: 1150359)
+UmaCtfAdapterTest:testPriceDisputedRevertNotOO() (gas: 11944)
+UmaCtfAdapterTest:testProposed() (gas: 682381)
+UmaCtfAdapterTest:testReady() (gas: 780512)
+UmaCtfAdapterTest:testReset() (gas: 756570)
+UmaCtfAdapterTest:testResetAlreadyReset() (gas: 940335)
 UmaCtfAdapterTest:testResetRevertNotInitialized() (gas: 17468)
-UmaCtfAdapterTest:testResetRevertResolved() (gas: 773205)
-UmaCtfAdapterTest:testResolve() (gas: 768886)
-UmaCtfAdapterTest:testResolveIgnorePrice() (gas: 1352578)
-UmaCtfAdapterTest:testResolveNo() (gas: 728760)
-UmaCtfAdapterTest:testResolveRevertAlreadyResolved() (gas: 770772)
-UmaCtfAdapterTest:testResolveRevertNotInitialized() (gas: 12872)
-UmaCtfAdapterTest:testResolveRevertPaused() (gas: 575854)
-UmaCtfAdapterTest:testResolveRevertUnavailablePrice() (gas: 575393)
-UmaCtfAdapterTest:testResolveUnknown() (gas: 788454)
-UmaCtfAdapterTest:testResolveYes() (gas: 768577)
+UmaCtfAdapterTest:testResetRevertResolved() (gas: 774063)
+UmaCtfAdapterTest:testResetWhenRefundExists() (gas: 1236223)
+UmaCtfAdapterTest:testResolve() (gas: 769743)
+UmaCtfAdapterTest:testResolveIgnorePrice() (gas: 1354088)
+UmaCtfAdapterTest:testResolveNo() (gas: 729355)
+UmaCtfAdapterTest:testResolveRevertAlreadyResolved() (gas: 771652)
+UmaCtfAdapterTest:testResolveRevertNotInitialized() (gas: 12895)
+UmaCtfAdapterTest:testResolveRevertPaused() (gas: 576210)
+UmaCtfAdapterTest:testResolveRevertUnavailablePrice() (gas: 575749)
+UmaCtfAdapterTest:testResolveUnknown() (gas: 789093)
+UmaCtfAdapterTest:testResolveYes() (gas: 769195)
 UmaCtfAdapterTest:testSetup() (gas: 23659)

src/UmaCtfAdapter.sol

@@ -148,11 +148,14 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
         bytes32 questionID = keccak256(ancillaryData);
         QuestionData storage questionData = questions[questionID];
 
-        if (questionData.reset) return;
+        if (questionData.reset) {
+            questionData.refund = true;
+            return;
+        }
 
         // If the question has not been reset previously, reset the question
         // Ensures that there are at most 2 OO Requests at a time for a question
-        _reset(address(this), questionID, questionData);
+        _reset(address(this), questionID, false, questionData);
     }
 
     /// @notice Checks if a question is initialized
@@ -199,8 +202,11 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
         if (!_isInitialized(questionData)) revert NotInitialized();
         if (questionData.resolved) revert Resolved();
 
+        // Refund the reward to the question creator if necessary
+        if (questionData.refund) _refund(questionData);
+
         // Reset the question, paying for the price request from the caller
-        _reset(msg.sender, questionID, questionData);
+        _reset(msg.sender, questionID, true, questionData);
     }
 
     /// @notice Allows an admin to resolve a CTF market in an emergency
@@ -215,6 +221,10 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
         if (block.timestamp < questionData.emergencyResolutionTimestamp) revert SafetyPeriodNotPassed();
 
         questionData.resolved = true;
+
+        // Refund the reward to the question creator if necessary
+        if (questionData.refund) _refund(questionData);
+
         ctf.reportPayouts(questionID, payouts);
         emit QuestionEmergencyResolved(questionID, payouts);
     }
@@ -270,6 +280,7 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
             resolved: false,
             paused: false,
             reset: false,
+            refund: false,
             rewardToken: rewardToken,
             creator: creator,
             ancillaryData: ancillaryData
@@ -332,11 +343,14 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
 
     /// @notice Reset the question by updating the requestTimestamp field and sending a new price request to the OO
     /// @param questionID - The unique questionID
-    function _reset(address requestor, bytes32 questionID, QuestionData storage questionData) internal {
+    function _reset(address requestor, bytes32 questionID, bool resetRefund, QuestionData storage questionData)
+        internal
+    {
         uint256 requestTimestamp = block.timestamp;
         // Update the question parameters in storage
         questionData.requestTimestamp = requestTimestamp;
         questionData.reset = true;
+        if (resetRefund) questionData.refund = false;
 
         // Send out a new price request with the new timestamp
         _requestPrice(
@@ -362,14 +376,18 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
         );
 
         // If the OO returns the ignore price, reset the question
-        if (price == _ignorePrice()) return _reset(address(this), questionID, questionData);
-
-        // Construct the payout array for the question
-        uint256[] memory payouts = _constructPayouts(price);
+        if (price == _ignorePrice()) return _reset(address(this), questionID, true, questionData);
 
         // Set resolved flag
         questionData.resolved = true;
 
+        // If refund flag is set, this indicates that the question's reward now sits on the Adapter.
+        // Refund the reward to the question creator on resolution
+        if (questionData.refund) _refund(questionData);
+
+        // Construct the payout array for the question
+        uint256[] memory payouts = _constructPayouts(price);
+
         // Resolve the underlying CTF market
         ctf.reportPayouts(questionID, payouts);
 
@@ -382,6 +400,10 @@ contract UmaCtfAdapter is IUmaCtfAdapter, Auth, BulletinBoard, IOptimisticReques
         );
     }
 
+    function _refund(QuestionData storage questionData) internal {
+        return TransferHelper._transfer(questionData.rewardToken, questionData.creator, questionData.reward);
+    }
+
     function _isFlagged(QuestionData storage questionData) internal view returns (bool) {
         return questionData.emergencyResolutionTimestamp > 0;
     }

src/interfaces/IUmaCtfAdapter.sol

@@ -19,6 +19,8 @@ struct QuestionData {
     bool paused;
     /// @notice Flag marking whether a question has been reset. A question can only be reset once
     bool reset;
+    /// @notice Flag marking whether a question's reward should be refunded.
+    bool refund;
     /// @notice ERC20 token address used for payment of rewards, proposal bonds and fees
     address rewardToken;
     /// @notice The address of the question creator

src/libraries/TransferHelper.sol

@@ -14,4 +14,12 @@ library TransferHelper {
     function _transferFromERC20(address token, address from, address to, uint256 amount) internal {
         SafeTransferLib.safeTransferFrom(ERC20(token), from, to, amount);
     }
+
+    /// @notice Transfers tokens from the current address to the given destination
+    /// @param token    - The contract address of the token to be transferred
+    /// @param to       - The destination address of the transfer
+    /// @param amount   - The amount to be transferred
+    function _transfer(address token, address to, uint256 amount) internal {
+        SafeTransferLib.safeTransfer(ERC20(token), to, amount);
+    }
 }