hardhat-zksync-upgradable

Guide on using the hardhat-zksync-upgradable plugin.


The hardhat-zksync-upgradable plugin is a Hardhat plugin that supports end-to-end pipelines for deploying and updating upgradable smart contracts on the Validium network.

The plugin is based on @openzeppelin/upgrades-corearrow-up-right plugin for deploying and managing upgradeable smart contracts on the Ethereum network. The hardhat-zksync-upgradable plugin provides an easy-to-use interface for interacting with the OpenZeppelin Upgrades Pluginsarrow-up-right within a Hardhat environment on Validium.

Ensure you are using the correct version of the plugin with ethers:

  • For plugin version <1.0.0:

    • Compatible with ethers v5.

  • For plugin version ≥1.0.0:

    • Compatible with ethers v6 (⭐ Recommended)

Examples are adopted for plugin version >=1.0.0Ensure that you're using the correct version of OpenZeppelin Contracts Upgradable for compatibility with your plugin:

  • For plugin version <1.6.0:

    • Compatible with @openzeppelin/contracts-upgradeable v4.

  • For plugin version ≥1.7.0:

    • Compatible with @openzeppelin/contracts-upgradeable v5 (⭐ Recommended)

Installation

Current version of the upgradable plugin does not support the latest version of the @openzeppelin/upgrades-core package.

@matterlabs/hardhat-zksync-upgradablearrow-up-right

Add the latest version of this plugin to your project with the following command:

Configuration

After installing it, add the plugin to your hardhat.config.ts file:

Deploying proxies

The plugin supports three types of proxies: Transparent upgradable proxies, UUPS proxies, and beacon proxies.

Upgradability methods are all part of the zkUpgrades property in the HardhatRuntimeEnvironment and you only need to interact with it in order to deploy or upgrade your contracts.

For the following examples, we use the simple Box smart contract:

In the examples below, we assume that the Box contract is compiled and its artifact loaded using Deployer class from the hardhat-zksync-deploy plugin. More info on how to compile and load the contract can be found in the Hardhat getting started page.

Transparent upgradable proxies

Transparent upgradable proxies provide a way to upgrade a smart contract without changing its address or requiring any change in the contract's interaction code. With transparent proxies, a contract's address is owned by a proxy contract, which forwards all calls to the actual contract implementation. When a new implementation is deployed, the proxy can be upgraded to point to the new implementation, allowing for seamless upgrades without requiring changes to the contract's interaction code.

To deploy a simple upgradable contract on ZKsync Era local setup, first create a test wallet and add it to the new Deployer.

After that, load the Box artifact and call the deployProxy method from the zkUpgrades hre property.

The deployProxy method deploys your implementation contract on ZKsync Era, deploys the proxy admin contract, and finally, deploys the transparent proxy.

Full deploy proxy script

Run the script with:

  • deployProxy method (and other deploy/upgrade methods from the zkUpgrades) needs to know which wallet to use to deploy smart contracts.

  • For this reason, the wallet needs to have a configured provider that connects it to the specific ZKsync network.

  • This provider is configured in the hardhat config file, by stating the RPC url of the network to connect to.

Hardhat config

Since the provider was instantiated on creating the Deployer class, based on your Hardhat configuration, we only have to pass the deployer.zkWallet and be sure that the correct provider is already set.

On the other hand, if you need to explicitly set the provider, do that with the code below:

UUPS proxies

If you want to use the plugin's UUPS proxy functionality, use zksolc version >=1.3.9.

The UUPS proxy pattern is similar to the transparent proxy pattern, except that the upgrade is triggered via the logic contract instead of from the proxy contract.

For the UUPS deployment example, we use a slightly modified smart contract called BoxUups.

The main difference between the Box and BoxUups contracts is that the latter implements both UUPSUpgradeable and OwnableUpgradeable interfaces and has a special function _authorizeUpgrade which can only be called by the contract owner.

You can find more info about how UUPS works in OpenZeppelin's documentationarrow-up-right.

To deploy the UUPS contract, use the same script as for the transparent upgradable proxy.

When you run the script, the plugin detects that the proxy type is UUPS, it executes the deployment, and saves the deployment info in your manifest file.

Beacon proxies

Beacon proxies are a more advanced form of proxy that use an intermediate contract (called the Beacon contract) to delegate calls to a specific implementation contract.

Beacon proxies enable a more advanced upgrade pattern, where multiple implementation contracts can be deployed and "hot-swapped" on the fly with no disruption to the contract's operation.

This allows for more advanced upgrade patterns, such as adding or removing functionality while minimizing downtime.

  1. Start by creating a Deployer for the ZKsync Era network and load the Box artifact:

  2. Deploy the beacon contract using deployBeacon method from the zkUpgrades

  3. Use the deployBeaconProxy method which receives the ZKsync Era wallet, beacon contract, and the implementation (Box) contract with its arguments.

After that, your beacon proxy contract is deployed on the network, and you can interact with it.

Full code for deploy beacon

Run the script with:

Implementation addresses check

Once you deploy the proxy contract, all interactions with your implementation contract go through it.

If you invoke the deployProxy function multiple times for a single implementation contract, several proxies will be created, but the implementation contract will remain the same for all of them. This means we can optimize the process to check for the existing implementation addresses before deploying a new proxy, instead of deploying a new implementation contract every time.

The upgradable plugin saves this information in the manifest file. This file will be created in your project's .upgradable folder. The manifest file is created per network, meaning you will have different data saved for upgrading contracts on the local setup and ZKsync Era networks.

Upgrading proxies

Validations

In order for a smart contract implementation to be upgradable, it has to follow specific rulesarrow-up-right.

  • The current version of the hardhat-zksync-upgradable plugin does NOT support all the validation checks.

  • This means that it is the users responsibility to check if the new implementation they want to upgrade follows the predefined standards.

  • At the time of writing, we are working on implementing those checks within the plugin itself, and the plan for subsequent releases is to support them natively.

Upgradable examples

The following examples use the BoxV2 contract as a new implementation for the Box proxy.

Upgrade transparent proxy

To upgrade the implementation of the transparent upgradeable contract, use the upgradeProxy method from the zkUpgrades.

upgradeProxy receives 3 arguments:

  • A ZKsync Era wallet.

  • The address of the previously deployed box proxy.

  • The artifact containing the new Box2 implementation.

Upgrade UUPS proxy

Similar to the deployment script, there are no modifications needed to upgrade the implementation of the UUPS contract, compared to upgrading the transparent upgradable contract. The only difference is that we use the BoxUupsV2 as a new implementation contract.

Upgrade proxy script snippet:

Upgrade beacon proxy

Beacon proxy implementation can be upgraded using a similarly structured method from the zkUpgrades called upgradeBeacon. For example:

The example below deploys and upgrades a smart contract using a beacon proxy:

Run the script with:

Proxy verification

To use proxy verification functionality, you must use the hardhat-zksync-verify plugin version >=0.1.8

The hardhat-zksync-upgradable plugin supports proxy verification, which means you can verify all the contracts deployed during the proxy deployment with a single verify command.

To use the verification functionality, you first need to import the hardhat-zksync-verify plugin before the hardhat-zksync-upgradable plugin in your hardhat.config.ts file:

To verify all the deployed contracts, simply run the verify command with the proxy address as an argument:

This command will verify the implementation related to the proxy, the proxy contract itself, and all the smart contracts included in the specific deployment process, such as a proxy admin smart contract or a beacon smart contract.

Proxy validations

The hardhat-zksync-upgradable plugin has built-in checks to ensure that your smart contract's newest implementation version follows the necessary requirements when upgrading your smart contract.

You can learn more about what those restrictions are in OpenZeppelin's documentationarrow-up-right.

Proxy gas fee estimation

Should you wish to estimate the total gas used throughout the proxy deployment process, consider utilizing the upgradable plugin's gas estimation functions. We offer three types of gas estimation functions for your convenience:

  • estimateGasProxy

  • estimateGasBeacon

  • estimateGasBeaconProxy

In the examples provided below, we will use the a Box contract and the deployer in the same way we used them in the previous examples:

To estimate the deployment fee for the Transparent upgradable proxies and UUPS proxies, use the estimateGasProxy method from the zkUpgrades.estimation. This method calculates the fee for deploying the implementation contract, transparent proxy/UUPS contract, and the ProxyAdmin smart contract.

Transparent proxyUUPS proxy

To estimate the deployment fee for the beacon contract and its corresponding implementation, use the estimateGasBeacon method:

If you want to get the estimation for the beacon proxy contract, please use the estimateGasBeaconProxy method:

Each of these methods totals the fee for every contract in their respective pipeline, displays the cost on the console, and returns the cumulative sum. If you prefer not to see the individual estimations, introduce the parameter quiet as the final parameter in any method to receive only the returned sum.

Commands

Please consider that while the provided commands enable contract deployment and upgrading, not all arguments may be available. If these commands lack the required functionality, it may be necessary to utilize scripting for a more comprehensive approach.

Configuration

To extend the configuration to support commands, we need to add an accounts field to the specific network configuration in the networks section of the hardhat.config.ts file. This accounts field can support an array of private keys or a mnemonic object and represents accounts that will be used as wallet automatically.

  • accounts represents a list of the private keys or mnemonic object for the account used in the deployment or in the upgrade process. accounts object will automatically be populated with rich accounts if used network is ZKsync Era Test Node or zksync-cli Local Node To establish a default index per network, which is by default 0, you can include a deployerAccounts section in your hardhat.config.ts file.

  • deployerAccounts represents an object where the default index of the accounts is provided and automatically used in the upgradable commands described below. If the network name is not specified inside the object, the default index of the account will be 0. We can change and deafult index for not specified networks if we override default name with index that we want.

Command list

Automatically determine whether the deployment requires a Transparent or UUPS proxy, and deploy all necessary contracts accordingly. If the Transparent proxy is chosen, the deployment will include the implementation, admin, and proxy. Alternatively, selecting the UUPS proxy will result in deploying the implementation and proxy.

Upgrade UUPS or Transparent implementation on the specified network.

Initiates the deployment of the specified implementation, beacon, and proxy on the specified network.

yarn hardhat upgrade-zksync:beacon --contract-name <contract name or FQN> --beacon-address <beacon address> [--deployment-type <deployment type>] [--no-compile]

Upgrade beacon implementation on the specified network.

  • --contract-name <contract name or FQN> - contract name or FQN, required argument in all tasks, e.g. hardhat deploy-zksync:proxy --contract-name SomeContract.

  • <constructor arguments> - list of constructor arguments, e.g. hardhat deploy-zksync:proxy --contract-name Greeter 'Hello'.

  • --constructor-args <module name> - name of javascript module containing complex constructor arguments. Works only if <constructor arguments> are not provided, e.g. hardhat deploy-zksync:contract --contract-name ComplexContract --constructor-args args.js. Example of args.js :

  • --beacon-address <beacon address> - deployed beacon contract address, e.g. yarn hardhat upgrade-zksync:beacon --contract-name BoxV2 --beacon-address 0x4bbeEB066eD09B7AEd07bF39EEe0460DFa261520.

  • --proxy-address <proxy address> - deployed proxy contract address, e.g. yarn hardhat upgrade-zksync:proxy --contract-name BoxV2 --proxy-address 0x4bbeEB066eD09B7AEd07bF39EEe0460DFa261520.

  • --initializer <initializer method> - initializer method name present in the contract, e.g. hardhat deploy-zksync:proxy --contract-name Contract --initializer store. If this parameter is omitted, the default value will be initialize.

  • --initial-owner - specify inital contract owner, e.g. hardhat deploy-zksync:beacon --contract-name Contract --initial-owner 0xa61464658AfeAf65CccaaFD3a512b69A83B77618. If this argument is omitted wallet address will be used.

  • --no-compile- skip the compilation process, e.g. hardhat deploy-zksync:beacon --contract-name Contract --no-compile.

  • --deployment-type - specify which deployer smart contract function will be called. Permissible values for this parameter include create, create2, createAccount, and create2Account. If this parameter is omitted, the default value will be create, e.g. hardhat deploy-zksync:beacon --contract-name Greeter 'Hello' --deployment-type create2.

The account used for deployment will be the one specified by the deployerAccount configuration within the hardhat.config.ts file. If no such configuration is present, the account with index 0 will be used.

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