xdeployer 💥

Hardhat plugin to deploy your smart contracts across multiple Ethereum Virtual Machine (EVM) chains with the same deterministic address.

What

This plugin will help you make easier and safer usage of the CREATE2 EVM opcode. CREATE2 can be used to compute in advance the address where a smart contract will be deployed, which allows for interesting new mechanisms known as counterfactual interactions.

Installation

npm install --save-dev xdeployer @nomiclabs/hardhat-ethers @openzeppelin/contracts

Or if you are using Yarn:

yarn add --dev xdeployer @nomiclabs/hardhat-ethers @openzeppelin/contracts

Note: This plugin uses the optional chaining operator (?.). Optional chaining is not supported in Node.js v13 and below.

Import the plugin in your hardhat.config.js:

require("xdeployer");

Or if you are using TypeScript, in your hardhat.config.ts:

import "xdeployer";

Required Plugins

• @nomiclabs/hardhat-ethers
• @openzeppelin/contracts

Tasks

This plugin provides the xdeploy task, which allows you to deploy your smart contracts across multiple EVM chains with the same deterministic address:

npx hardhat xdeploy

Environment Extensions

This plugin does not extend the environment.

Configuration

You need to add the following configurations to your hardhat.config.js file:

module.exports = {
  networks: {
    mainnet: { ... }
  },
  xdeploy: {
    contract: "YOUR_CONTRACT_NAME_TO_BE_DEPLOYED",
    constructorArgsPath: "PATH_TO_CONSTRUCTOR_ARGS",
    salt: "YOUR_SALT_MESSAGE",
    signer: "SIGNER_PRIVATE_KEY",
    networks: ["LIST_OF_NETWORKS"],
    rpcUrls: ["LIST_OF_RPCURLS"],
    gasLimit: "GAS_LIMIT",
  },
};

Or if you are using TypeScript, in your hardhat.config.ts:

const config: HardhatUserConfig = {
  networks: {
    mainnet: { ... }
  },
  xdeploy: {
    contract: "YOUR_CONTRACT_NAME_TO_BE_DEPLOYED",
    constructorArgsPath: "PATH_TO_CONSTRUCTOR_ARGS",
    salt: "YOUR_SALT_MESSAGE",
    signer: "SIGNER_PRIVATE_KEY",
    networks: ["LIST_OF_NETWORKS"],
    rpcUrls: ["LIST_OF_RPCURLS"],
    gasLimit: "GAS_LIMIT",
  },
};

The parameters constructorArgsPath and gasLimit are optional. The salt parameter is a random value (32 byte string) used to create the contract address. If you have previously deployed the same contract with the identical salt, the contract creation transaction will fail due to EIP-684. For more details, see also here.

Example:

xdeploy: {
  contract: "ERC20Mock",
  constructorArgsPath: "./deploy-args.ts",
  salt: "WAGMI",
  signer: process.env.PRIVATE_KEY,
  networks: ["hardhat", "rinkeby", "kovan"],
  rpcUrls: ["hardhat", process.env.RINKEBY_URL, process.env.KOVAN_URL],
  gasLimit: 1.2 * 10 ** 6,
},

The current available networks are:

• Local:
  • localhost
  • hardhat
• EVM-Based Test Networks:
  • rinkeby
  • ropsten
  • kovan
  • goerli
  • bscTestnet
  • optimismTestnet
  • arbitrumTestnet
  • mumbai
  • hecoTestnet
  • fantomTestnet
  • fuji
  • sokol
  • moonbaseAlpha
  • alfajores
  • auroraTestnet
  • harmonyTestnet
  • spark
  • cronosTestnet
• EVM-Based Production Networks:
  • ethMain
  • bscMain
  • optimismMain
  • arbitrumMain
  • polygon
  • hecoMain
  • fantomMain
  • avalanche
  • gnosis
  • moonriver
  • moonbeam
  • celo
  • auroraMain
  • harmonyMain
  • autobahn
  • fuse
  • cronos

Note that you must ensure that your deployment account has sufficient funds on all target networks. In addition, please be aware that gnosis refers to the previously known xDai chain.

Local Deployment

If you also want to test deploy your smart contracts on "hardhat" or "localhost", you must first add the following Solidity file called Create2DeployerLocal.sol to your contracts/ folder:

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "xdeployer/src/contracts/Create2Deployer.sol";

contract Create2DeployerLocal is Create2Deployer {}

For this kind of deployment, you must set the Solidity version in the hardhat.config.js or hardhat.config.ts file to 0.8.9.

The RPC URL for hardhat is simply hardhat, while for localhost you must first run npx hardhat node, which defaults to http://127.0.0.1:8545. Note that localhost in Node.js v17 favours IPv6, which means that you need to configure the network endpoint of localhost in hardhat.config.js or hardhat.config.ts like this:

networks: {
  localhost: {
    url: [::1],
  },
}

Eventually, it is important to note that the local deployment does not generate the same deterministic address as on all live test/production networks, since the address of the smart contract that calls the opcode CREATE2 differs locally from the live test/production networks. I recommend using local deployments for general testing, for example to understand the correct gasLimit target size.

Further Considerations

The constructor arguments file must have an exportable field called data in case you are using TypeScript:

const data = [
  "arg1",
  "arg2",
  ...
];
export { data };

BigInt literals (e.g. 100000000000000000000n) can be used for the constructor arguments if you set target: ES2020 in your tsconfig.json file. See also here for an example.

If you are using common JavaScript:

module.exports = [
  "arg1",
  "arg2",
  ...
];

The gasLimit field is set to 1'500'000 by default because the CREATE2 operations are a complex sequence of opcode executions. Usually the providers do not manage to estimate the gasLimit for these calls, so a predefined value is set.

The contract creation transaction is displayed on Etherscan (or any other block explorer) as a so-called internal transaction. An internal transaction is an action that is occurring within, or between, one or multiple smart contracts. In other words, it is initiated inside the code itself, rather than externally, from a wallet address controlled by a human. For more details on why it works this way, see here.

Usage

npx hardhat xdeploy

Usage With Truffle

Truffle suite users can leverage the Hardhat plugin hardhat-truffle5 (or if you use Truffle v4 hardhat-truffle4) to integrate with TruffleContract from Truffle v5. This plugin allows tests and scripts written for Truffle to work with Hardhat.

How It Works

EVM opcodes can only be called via a smart contract. I have deployed a helper smart contract Create2Deployer with the same address across all the available networks to make easier and safer usage of the CREATE2 EVM opcode. During your deployment, the plugin will call this contract.

A Note on SELFDESTRUCT

Using the CREATE2 EVM opcode always allows to redeploy a new smart contract to a previously selfdestructed contract address. However, if a contract creation is attempted, due to either a creation transaction or the CREATE/CREATE2 EVM opcode, and the destination address already has either nonzero nonce, or non-empty code, then the creation throws immediately, with exactly the same behavior as would arise if the first byte in the init code were an invalid opcode. This applies retroactively starting from genesis.

A Note on the Contract Creation Transaction

It is important to note that the msg.sender of the contract creation transaction is the helper smart contract Create2Deployer with address 0x13b0D85CcB8bf860b6b79AF3029fCA081AE9beF2. If you are relying on common smart contract libraries such as OpenZeppelin for your smart contract, which set certain constructor arguments to msg.sender (e.g. owner), you will need to change these arguments to tx.origin so that they are set to your deployer's EOA address. For another workaround, see here.

Caveat: Please familiarise yourself with the security considerations concerning tx.origin. You can find more information about it, e.g. here.

Donation

I am a strong advocate of the open-source and free software paradigm. However, if you feel my work deserves a donation, you can send it to this address: 0x07bF3CDA34aA78d92949bbDce31520714AB5b228. I can pledge that I will use this money to help fix more existing challenges in the Ethereum ecosystem 🤝.