Add PayForGas event and reverty flag; add price check; add unit tests

compound-finance · Apr 30, 2024 · 7354cac · 7354cac
1 parent 778b6f5
commit 7354cac
Show file tree

Hide file tree

Showing 4 changed files with 503 additions and 31 deletions.
diff --git a/src/quark-core-scripts/src/Paycall.sol b/src/quark-core-scripts/src/Paycall.sol
@@ -15,12 +15,10 @@ contract Paycall {
 
     event PayForGas(address indexed payer, address indexed payee, address indexed paymentToken, uint256 amount);
 
+    error BadPrice();
     error InvalidCallContext();
     error TransactionTooExpensive();
 
-    /// @notice This contract's address
-    address internal immutable scriptAddress;
-
     /// @notice Native token (e.g. ETH) based price feed address (e.g. ETH/USD, ETH/BTC)
     address public immutable nativeTokenBasedPriceFeedAddress;
 
@@ -30,6 +28,9 @@ contract Paycall {
     /// @notice Flag for indicating if reverts from the call should be propagated or swallowed
     bool public immutable propagateReverts;
 
+    /// @notice This contract's address
+    address internal immutable scriptAddress;
+
     /// @notice Constant buffer for gas overhead
     /// This is a constant to account for the gas used by the Paycall contract itself that's not tracked by gasleft()
     uint256 internal constant GAS_OVERHEAD = 75000;
@@ -52,7 +53,7 @@ contract Paycall {
         // Note: Assumes the native token has 18 decimals
         divisorScale = 10
             ** uint256(
-                18 + AggregatorV3Interface(ethBasedPriceFeedAddress).decimals()
+                18 + AggregatorV3Interface(nativeTokenBasedPriceFeedAddress).decimals()
                     - IERC20Metadata(paymentTokenAddress).decimals()
             );
     }
@@ -82,6 +83,10 @@ contract Paycall {
         }
 
         (, int256 price,,,) = AggregatorV3Interface(nativeTokenBasedPriceFeedAddress).latestRoundData();
+        if (price <= 0) {
+            revert BadPrice();
+        }
+
         uint256 gasUsed = gasInitial - gasleft() + GAS_OVERHEAD;
         uint256 paymentAmount = gasUsed * tx.gasprice * uint256(price) / divisorScale;
         if (paymentAmount > maxPaymentCost) {

diff --git a/src/quark-core-scripts/src/Quotecall.sol b/src/quark-core-scripts/src/Quotecall.sol
@@ -13,20 +13,26 @@ import "openzeppelin/token/ERC20/extensions/IERC20Metadata.sol";
 contract Quotecall {
     using SafeERC20 for IERC20;
 
-    error InvalidCallContext();
-    error TransactionOutsideQuote();
+    event PayForGas(address indexed payer, address indexed payee, address indexed paymentToken, uint256 amount);
 
-    /// @notice This contract's address
-    address internal immutable scriptAddress;
+    error BadPrice();
+    error InvalidCallContext();
+    error QuoteToleranceExceeded();
 
     /// @notice Native token (e.g. ETH) based price feed address (e.g. ETH/USD, ETH/BTC)
     address public immutable nativeTokenBasedPriceFeedAddress;
 
     /// @notice Payment token address
     address public immutable paymentTokenAddress;
 
-    /// @notice The max delta in basis points
-    uint256 public immutable maxDeltaBps;
+    /// @notice The max delta precentage allowed between the quoted cost and actual cost of the call
+    uint256 public immutable maxDeltaPercentage;
+
+    /// @notice Flag for indicating if reverts from the call should be propagated or swallowed
+    bool public immutable propagateReverts;
+
+    /// @notice This contract's address
+    address internal immutable scriptAddress;
 
     /// @notice Constant buffer for gas overhead
     /// This is a constant to accounted for the gas used by the Quotecall contract itself that's not tracked by gasleft()
@@ -35,22 +41,32 @@ contract Quotecall {
     /// @notice Difference in scale between the native token + price feed and the payment token, used to scale the payment token
     uint256 internal immutable divisorScale;
 
+    /// @dev The scale for percentages, used for `maxDeltaPercentage` (e.g. 1e18 = 100%)
+    uint256 internal constant PERCENTAGE_SCALE = 1e18;
+
     /**
      * @notice Constructor
      * @param nativeTokenBasedPriceFeedAddress_ Native token based price feed address that follows Chainlink's AggregatorV3Interface correlated to the payment token
      * @param paymentTokenAddress_ Payment token address
-     * @param maxDeltaBps_ Maximal allowed delta in basis points (100 bps = 1%)
+     * @param maxDeltaPercentage_ Maximum allowed delta percentage between the quoted cost and actual cost of the call (1e18 = 100%)
+     * @param propagateReverts_ Flag for indicating if reverts from the call should be propagated or swallowed
      */
-    constructor(address nativeTokenBasedPriceFeedAddress_, address paymentTokenAddress_, uint256 maxDeltaBps_) {
+    constructor(
+        address nativeTokenBasedPriceFeedAddress_,
+        address paymentTokenAddress_,
+        uint256 maxDeltaPercentage_,
+        bool propagateReverts_
+    ) {
         nativeTokenBasedPriceFeedAddress = nativeTokenBasedPriceFeedAddress_;
         paymentTokenAddress = paymentTokenAddress_;
-        maxDeltaBps = maxDeltaBps_;
+        maxDeltaPercentage = maxDeltaPercentage_;
+        propagateReverts = propagateReverts_;
         scriptAddress = address(this);
 
         // Note: Assumes the native token has 18 decimals
         divisorScale = 10
             ** uint256(
-                18 + AggregatorV3Interface(ethBasedPriceFeedAddress).decimals()
+                18 + AggregatorV3Interface(nativeTokenBasedPriceFeedAddress).decimals()
                     - IERC20Metadata(paymentTokenAddress).decimals()
             );
     }
@@ -59,36 +75,39 @@ contract Quotecall {
      * @notice Execute delegatecall on a contract and pay tx.origin for gas
      * @param callContract Contract to call
      * @param callData Encoded calldata for call
-     * @param quote The quoted network fee for this transaction
+     * @param quotedAmount The quoted network fee for this transaction, in units of the payment token
      * @return Return data from call
      */
-    function run(address callContract, bytes calldata callData, uint256 quote)
-        external
-        returns (bytes memory)
-    {
+    function run(address callContract, bytes calldata callData, uint256 quotedAmount) external returns (bytes memory) {
         uint256 gasInitial = gasleft();
         // Ensures that this script cannot be called directly and self-destructed
         if (address(this) == scriptAddress) {
             revert InvalidCallContext();
         }
 
-        IERC20(paymentTokenAddress).safeTransfer(tx.origin, quote);
+        IERC20(paymentTokenAddress).safeTransfer(tx.origin, quotedAmount);
+        emit PayForGas(address(this), tx.origin, paymentTokenAddress, quotedAmount);
 
         (bool success, bytes memory returnData) = callContract.delegatecall(callData);
-        if (!success) {
+        if (!success && propagateReverts) {
             assembly {
                 revert(add(returnData, 32), mload(returnData))
             }
         }
 
-        (, int256 price,,,) = AggregatorV3Interface(ethBasedPriceFeedAddress).latestRoundData();
+        (, int256 price,,,) = AggregatorV3Interface(nativeTokenBasedPriceFeedAddress).latestRoundData();
+        if (price <= 0) {
+            revert BadPrice();
+        }
+
         uint256 gasUsed = gasInitial - gasleft() + GAS_OVERHEAD;
-        uint256 expectedAmount = gasUsed * tx.gasprice * uint256(price) / divisorScale;
-        uint256 actualDelta = expectedAmount > quote ? expectedAmount - quote : quote - expectedAmount;
-        uint256 actualDeltaBps = actualDelta * 10000 / quote;
+        uint256 actualAmount = gasUsed * tx.gasprice * uint256(price) / divisorScale;
+        uint256 actualDelta = actualAmount > quotedAmount ? actualAmount - quotedAmount : quotedAmount - actualAmount;
+        uint256 actualDeltaPercentage = actualDelta * PERCENTAGE_SCALE / quotedAmount;
+        emit PayForGas(address(this), tx.origin, paymentTokenAddress, actualAmount);
 
-        if (actualDeltaBps > maxDelta) {
-            revert TransactionOutsideQuote();
+        if (actualDeltaPercentage > maxDeltaPercentage) {
+            revert QuoteToleranceExceeded();
         }
 
         return returnData;

diff --git a/test/quark-core-scripts/Paycall.t.sol b/test/quark-core-scripts/Paycall.t.sol
@@ -52,7 +52,8 @@ contract PaycallTest is Test {
     bytes multicall = new YulHelper().getCode("Multicall.sol/Multicall.json");
     bytes ethcall = new YulHelper().getCode("Ethcall.sol/Ethcall.json");
     bytes reverts = new YulHelper().getCode("Reverts.sol/Reverts.json");
-    // Paycall has its contructor with 2 parameters
+
+    // Paycall has its contructor with 3 parameters
     bytes paycall;
     bytes paycallUSDT;
     bytes paycallWBTC;
@@ -108,10 +109,13 @@ contract PaycallTest is Test {
     /* ===== call context-based tests ===== */
 
     function testInitializeProperlyFromConstructor() public {
-        address storedPriceFeedAddress = Paycall(paycallAddress).ethBasedPriceFeedAddress();
-        address stpredPaymentTokenAddress = Paycall(paycallAddress).paymentTokenAddress();
+        address storedPriceFeedAddress = Paycall(paycallAddress).nativeTokenBasedPriceFeedAddress();
+        address storedPaymentTokenAddress = Paycall(paycallAddress).paymentTokenAddress();
+        bool storedPropagateReverts = Paycall(paycallAddress).propagateReverts();
+
         assertEq(storedPriceFeedAddress, ETH_USD_PRICE_FEED);
-        assertEq(stpredPaymentTokenAddress, USDC);
+        assertEq(storedPaymentTokenAddress, USDC);
+        assertEq(storedPropagateReverts, true);
     }
 
     function testRevertsForInvalidCallContext() public {