fix: gas estimation on zksync for safe accounts (#623)

* fix: gas estimation on zksync for safe accounts

* fix: console log

* fix: bump default gas estimation

* fix: test

Author: grothem

packages/contract-helpers/src/commons/gasStation.test.ts

@@ -1,5 +1,6 @@
 import { BigNumber, providers } from 'ethers';
 import { estimateGas, estimateGasByNetwork } from './gasStation';
+import { ChainId } from './types';
 
 describe('gasStation', () => {
   const provider: providers.Provider = new providers.JsonRpcProvider();
@@ -41,5 +42,33 @@ describe('gasStation', () => {
       const gas = await estimateGasByNetwork(tx, provider, 10);
       expect(gas).toEqual(BigNumber.from(110));
     });
+    it('Expects to return 350000 for zksync when connected with contract address', async () => {
+      jest
+        .spyOn(provider, 'getNetwork')
+        .mockImplementationOnce(async () =>
+          Promise.resolve({ chainId: ChainId.zksync, name: 'zksync' }),
+        );
+
+      jest
+        .spyOn(provider, 'getCode')
+        .mockImplementationOnce(async () => Promise.resolve('0x1234'));
+
+      const gas = await estimateGasByNetwork({ from: '0x123abc' }, provider);
+      expect(gas).toEqual(BigNumber.from(350000));
+    });
+    it('Expects to return default for zksync when connected with EOA', async () => {
+      jest
+        .spyOn(provider, 'getNetwork')
+        .mockImplementationOnce(async () =>
+          Promise.resolve({ chainId: ChainId.zksync, name: 'zksync' }),
+        );
+
+      jest
+        .spyOn(provider, 'getCode')
+        .mockImplementationOnce(async () => Promise.resolve('0x'));
+
+      const gas = await estimateGasByNetwork({ from: '0x123abc' }, provider);
+      expect(gas).toEqual(BigNumber.from(130));
+    });
   });
 });

packages/contract-helpers/src/commons/gasStation.ts

@@ -21,8 +21,21 @@ export const estimateGasByNetwork = async (
   provider: providers.Provider,
   gasSurplus?: number,
 ): Promise<BigNumber> => {
-  const estimatedGas = await provider.estimateGas(tx);
   const providerNework: providers.Network = await provider.getNetwork();
+  if (providerNework.chainId === ChainId.zksync && tx.from) {
+    /**
+     *  Trying to estimate gas on zkSync when connected with a smart contract address
+     *  will fail. In that case, we'll just return a default value for all transactions.
+     *
+     *  See here for more details: https://github.com/zkSync-Community-Hub/zksync-developers/discussions/144
+     */
+    const data = await provider.getCode(tx.from);
+    if (data !== '0x') {
+      return BigNumber.from(350000);
+    }
+  }
+
+  const estimatedGas = await provider.estimateGas(tx);
 
   if (providerNework.chainId === ChainId.polygon) {
     return estimatedGas.add(estimatedGas.mul(POLYGON_SURPLUS).div(100));