Fix bug related to refunding of application budget if delivery fails (#42)

* Fix bug related to refunding of application budget if delivery doesn't succeed

* forge fmt

* Fix some yul error

* forge fmt

ethereum/contracts/coreRelayer/CoreRelayer.sol

@@ -358,7 +358,7 @@ contract CoreRelayer is CoreRelayerGovernance {
         uint256 postGas = gasleft();
 
         // refund unused gas budget
-        uint256 weiToRefund = 0;
+        uint256 weiToRefund = internalInstruction.applicationBudgetTarget;
         if (success) {
             weiToRefund = (internalInstruction.executionParameters.gasLimit - (preGas - postGas))
                 * internalInstruction.maximumRefundTarget / internalInstruction.executionParameters.gasLimit;
@@ -409,11 +409,11 @@ contract CoreRelayer is CoreRelayerGovernance {
             }
         }
 
+        uint256 applicationBudgetPaid = (success ? internalInstruction.applicationBudgetTarget : 0);
+        uint256 wormholeFeePaid = getForwardingRequest().isValid ? wormhole.messageFee() : 0;
+        uint256 relayerRefundAmount = msg.value - weiToRefund - applicationBudgetPaid - wormholeFeePaid;
         // refund the rest to relayer
-        msg.sender.call{
-            value: msg.value - weiToRefund - internalInstruction.applicationBudgetTarget
-                - (getForwardingRequest().isValid ? wormhole.messageFee() : 0)
-        }("");
+        msg.sender.call{value: relayerRefundAmount}("");
     }
 
     //REVISE, consider implementing this system into the RelayProvider.

ethereum/contracts/mock/MockRelayerIntegration.sol

@@ -74,7 +74,7 @@ contract MockRelayerIntegration is IWormholeReceiver {
             targetChain: targetChainId,
             targetAddress: relayer.toWormholeFormat(address(destination)),
             refundAddress: relayer.toWormholeFormat(address(refundAddress)), // This will be ignored on the target chain if the intent is to perform a forward
-            computeBudget: msg.value - 2 * wormhole.messageFee(),
+            computeBudget: msg.value - 2 * wormhole.messageFee() - applicationBudget,
             applicationBudget: applicationBudget, // not needed in this case.
             relayParameters: relayer.getDefaultRelayParams() //no overrides
         });

ethereum/forge-test/CoreRelayer.t.sol

@@ -357,6 +357,49 @@ contract TestCoreRelayer is Test {
         );
     }
 
+    function testFundsCorrectIfApplicationCallReverts(
+        GasParameters memory gasParams,
+        bytes memory message,
+        uint32 applicationBudget
+    ) public {
+        (uint16 SOURCE_CHAIN_ID, uint16 TARGET_CHAIN_ID, Contracts memory source, Contracts memory target) =
+            standardAssumeAndSetupTwoChains(gasParams, 1000000);
+
+        vm.recordLogs();
+
+        uint256 refundAddressBalance = target.refundAddress.balance;
+        uint256 relayerBalance = target.relayer.balance;
+        uint256 rewardAddressBalance = source.rewardAddress.balance;
+
+        uint256 payment = source.coreRelayer.quoteGasDeliveryFee(TARGET_CHAIN_ID, 21000, source.relayProvider)
+            + source.wormhole.messageFee() + applicationBudget;
+
+        source.integration.sendMessageGeneral{value: payment}(
+            abi.encodePacked(uint8(0), message),
+            TARGET_CHAIN_ID,
+            address(target.integration),
+            address(target.refundAddress),
+            applicationBudget,
+            1
+        );
+
+        genericRelayer(SOURCE_CHAIN_ID, 2);
+
+        uint256 USDcost = uint256(payment) * gasParams.sourceNativePrice
+            - (target.refundAddress.balance - refundAddressBalance) * gasParams.targetNativePrice;
+        uint256 relayerProfit = uint256(gasParams.sourceNativePrice)
+            * (source.rewardAddress.balance - rewardAddressBalance)
+            - gasParams.targetNativePrice * (relayerBalance - target.relayer.balance);
+
+        uint256 howMuchGasRelayerCouldHavePaidForAndStillProfited =
+            relayerProfit / gasParams.targetGasPrice / gasParams.targetNativePrice;
+
+        assertTrue(
+            USDcost == relayerProfit + 2 * map[SOURCE_CHAIN_ID].wormhole.messageFee() * gasParams.sourceNativePrice,
+            "We paid the exact amount"
+        );
+    }
+
     function testForward(GasParameters memory gasParams, bytes memory message) public {
         (uint16 SOURCE_CHAIN_ID, uint16 TARGET_CHAIN_ID, Contracts memory source, Contracts memory target) =
             standardAssumeAndSetupTwoChains(gasParams, 1000000);