🪁 Hardhat support custom errors (#719)

Author: yivlad

Diff for: .changeset/big-goats-guess.md

@@ -0,0 +1,5 @@
+---
+"@ethereum-waffle/chai": patch
+---
+
+Add support for custom errors in hardhat

Diff for: waffle-chai/src/matchers/revertedWith.ts

@@ -87,6 +87,13 @@ const decodeHardhatError = (error: any) => {
         return matches[1];
       }
     }
+    {
+      const regexp = new RegExp('VM Exception while processing transaction: reverted with custom error \'(.*)\'');
+      const matches = regexp.exec(errorString);
+      if (matches && matches.length >= 1) {
+        return matches[1];
+      }
+    }
     {
       const regexp = new RegExp('VM Exception while processing transaction: reverted with panic code ([a-zA-Z0-9]*)');
       const matches = regexp.exec(errorString);

Diff for: waffle-hardhat/contracts/CustomError.sol

@@ -0,0 +1,9 @@
+pragma solidity ^0.8.0;
+
+error CustomError(uint value);
+
+contract Matchers {
+  function doRevertWithCustomError() public pure {
+    revert CustomError(0);
+  }
+}

Diff for: waffle-hardhat/test/reverted.test.ts

@@ -3,7 +3,8 @@ import {expect} from 'chai';
 import {MockProvider} from 'ethereum-waffle';
 import {revertedTest, revertedWithTest} from '@ethereum-waffle/chai/test';
 import {ContractFactory} from 'ethers';
-import {abi, bytecode} from '../build/contracts/Panic.sol/Panic.json';
+import Panic from '../build/contracts/Panic.sol/Panic.json';
+import CustomError from '../build/contracts/CustomError.sol/Matchers.json';
 
 describe('INTEGRATION: Matchers: reverted', () => {
   const provider = waffle.provider as MockProvider;
@@ -29,7 +30,16 @@ it('Panic code', async () => {
   await waffle.provider.send('hardhat_reset', []);
   const wallets = waffle.provider.getWallets();
   const wallet = wallets[0];
-  const factory = new ContractFactory(abi, bytecode, wallet);
+  const factory = new ContractFactory(Panic.abi, Panic.bytecode, wallet);
   const panicContract = await factory.deploy();
   await expect(panicContract.panic()).to.be.revertedWith('panic code 0x32');
 });
+
+it('Handle custom error', async () => {
+  await waffle.provider.send('hardhat_reset', []);
+  const wallets = waffle.provider.getWallets();
+  const wallet = wallets[0];
+  const factory = new ContractFactory(CustomError.abi, CustomError.bytecode, wallet);
+  const matchers = await factory.deploy();
+  await expect(matchers.doRevertWithCustomError()).to.be.revertedWith('CustomError(0)');
+});