[v0.14] Add extra gas to account for EIP-150 reserved gas (#2003)

* Adds an extra to the tx estimate to account for EIP-150 reserved gas

* Fixes EIP-150 1/64 estimation math

---------

Co-authored-by: Santiago Aceñolaza <santiago@api3.org>

Author: dcroote

.changeset/blue-starfishes-help.md

@@ -0,0 +1,5 @@
+---
+"@api3/airnode-node": patch
+---
+
+Adds extra gas to estimate to account for EIP-150

packages/airnode-node/src/evm/fulfillments/api-calls.test.ts

@@ -656,8 +656,8 @@ describe('submitApiCall', () => {
             {
               level: 'INFO',
               message: `Gas limit is set to ${
-                73804 + 290001
-              } (AirnodeRrp: ${73804} + Fulfillment Call: ${290001}) for Request:${apiCall.id}.`,
+                73804 + 290001 + 5774
+              } (AirnodeRrp: ${73804} + Fulfillment Call: ${290001} + EIP150: ${5774}) for Request:${apiCall.id}.`,
             },
             { level: 'INFO', message: `Submitting API call fulfillment for Request:${apiCall.id}...` },
           ]);
@@ -686,7 +686,7 @@ describe('submitApiCall', () => {
             apiCall.fulfillFunctionId,
             '0x448b8ad3a330cf8f269f487881b59efff721b3dfa8e61f7c8fd2480389459ed3',
             '0xda6d5aa27f48aa951ba401c8a779645f7d1fa4a46a5e99eb7da04b4e059449a834ca1058c85dfe8117305265228f8cf7ae64c3ef3c4d1cc191f77807227dac461b',
-            { ...txOpts, gasLimit: ethers.BigNumber.from(73804 + 290001) }
+            { ...txOpts, gasLimit: ethers.BigNumber.from(73804 + 290001 + 5774) }
           );
           expect(failMock).not.toHaveBeenCalled();
         }
@@ -735,8 +735,8 @@ describe('submitApiCall', () => {
             {
               level: 'INFO',
               message: `Gas limit is set to ${
-                73804 + 290001
-              } (AirnodeRrp: ${73804} + Fulfillment Call: ${290001}) for Request:${apiCall.id}.`,
+                73804 + 290001 + 5774
+              } (AirnodeRrp: ${73804} + Fulfillment Call: ${290001} + EIP150: ${5774}) for Request:${apiCall.id}.`,
             },
             { level: 'INFO', message: `Submitting API call fulfillment for Request:${apiCall.id}...` },
             {
@@ -768,7 +768,7 @@ describe('submitApiCall', () => {
             apiCall.fulfillFunctionId,
             '0x448b8ad3a330cf8f269f487881b59efff721b3dfa8e61f7c8fd2480389459ed3',
             '0xda6d5aa27f48aa951ba401c8a779645f7d1fa4a46a5e99eb7da04b4e059449a834ca1058c85dfe8117305265228f8cf7ae64c3ef3c4d1cc191f77807227dac461b',
-            { ...txOpts, gasLimit: ethers.BigNumber.from(73804 + 290001) }
+            { ...txOpts, gasLimit: ethers.BigNumber.from(73804 + 290001 + 5774) }
           );
           expect(failMock).not.toHaveBeenCalled();
         }

packages/airnode-node/src/evm/fulfillments/api-calls.ts

@@ -316,15 +316,20 @@ export async function estimateGasAndSubmitFulfill(
   }
 
   const [airnodeRrpGasCost, fulfillmentCallGasCost] = estimateGasData;
-  const totalCost = airnodeRrpGasCost.add(fulfillmentCallGasCost);
+  const subTotalCost = airnodeRrpGasCost.add(fulfillmentCallGasCost);
+  // https://github.com/ethereum/EIPs/issues/114
+  // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-150.md
+  const eip150GasReserve = subTotalCost.div(63);
+  const totalGasCost = subTotalCost.add(eip150GasReserve);
+
   // If gas estimation is success, submit fulfillment without making static test call
   const gasLimitNoticeLog = logger.pend(
     'INFO',
-    `Gas limit is set to ${totalCost} (AirnodeRrp: ${airnodeRrpGasCost} + Fulfillment Call: ${fulfillmentCallGasCost}) for Request:${request.id}.`
+    `Gas limit is set to ${totalGasCost} (AirnodeRrp: ${airnodeRrpGasCost} + Fulfillment Call: ${fulfillmentCallGasCost} + EIP150: ${eip150GasReserve}) for Request:${request.id}.`
   );
   const [submitLogs, submitErr, submitData] = await submitFulfill(airnodeRrp, request, {
     ...options,
-    gasTarget: { ...options.gasTarget, gasLimit: totalCost },
+    gasTarget: { ...options.gasTarget, gasLimit: totalGasCost },
   });
   return [[...estimateGasLogs, gasLimitNoticeLog, ...submitLogs], submitErr, submitData];
 }