How to verify deployed solidity smart contracts with constructor arguments (WIP)

TLDR

This readme & plugin helps you verify the source code for your Solidity contracts. At the moment, it supports Etherscan-based explorers, explorers compatible with its API like Blockscout and Sourcify.

Steps

• Install hardhat-verify
• Import @nomicfoundation/hardhat-verify
• Add the following Etherscan and Sourcify configs
• Write your arguments.js
• Run npx hardhat verify --network sepolia --constructor-args arguments.js CONTRACT_ADDRESS

Installation

npm install --save-dev @nomicfoundation/hardhat-verify

Then if you are using TypeScript, add this to your hardhat.config.ts:

import "@nomicfoundation/hardhat-verify";

Add Etherscan and sourcify configs

You need to add the following Etherscan and Sourcify configs to your hardhat.config.js file:

module.exports = {
  networks: {
    mainnet: { ... }
  },
  etherscan: {
    // Your API key for Etherscan
    // Obtain one at https://etherscan.io/
    apiKey: "YOUR_ETHERSCAN_API_KEY"
  },
  sourcify: {
    // Disabled by default
    // Doesn't need an API key
    enabled: true
  }
};

Complex arguments

When the constructor has a complex argument list, you'll need to write a javascript module that exports the argument list. The expected format is the same as a constructor list for an ethers contract. For example, if you have a contract like this:

    constructor(
        bytes32[] memory _proposalNames,
        address _tokenContract,
        uint256 _targetBlockNumber
    ) {
        tokenContract = IMyToken(_tokenContract);
        targetBlockNumber = _targetBlockNumber;
        require(
          targetBlockNumber <= block.number,
          "TokenizedBallot: targetBlockNumber must be in the past"
        );
        for (uint i = 0; i < _proposalNames.length; i++) {
            proposals.push(Proposal({name: _proposalNames[i], voteCount: 0}));
        }
    }

Write your arguments.js

then you can use an arguments.js file like this:

const { toHex } = require("viem");

const proposals = ["pizza", "tacos", "donuts", "wings"];

const _proposalNames = proposals.map((name) => toHex(name, { size: 32 }));

module.exports = [
  _proposalNames,
  "0x3c9d658a9b358cf1985bc52c5476229e8b186f1f",
  "6564652",
];

Run npx hardhat verify

The module can then be loaded by the verify task when invoked like this:

npx hardhat verify --network sepolia --constructor-args arguments.js CONTRACT_ADDRESS

npx hardhat verify --network sepolia --constructor-args ballotArguments.js 0x3cac1e711919a503681d258ee38c01d5e1971f4d