contracts-bedrock/

README

Optimism Smart Contracts (Bedrock)

This package contains the smart contracts that compose the on-chain component of Optimism's upcoming Bedrock upgrade. We've tried to maintain 100% backwards compatibility with the existing system while also introducing new useful features. You can find detailed specifications for the contracts contained within this package here.

A style guide we follow for writing contracts can be found here.

Contracts Overview

Contracts deployed to L1

Name	Proxy Type	Description
L1CrossDomainMessenger	ResolvedDelegateProxy	High-level interface for sending messages to and receiving messages from Optimism
L1StandardBridge	L1ChugSplashProxy	Standardized system for transfering ERC20 tokens to/from Optimism
L2OutputOracle	Proxy	Stores commitments to the state of Optimism which can be used by contracts on L1 to access L2 state
OptimismPortal	Proxy	Low-level message passing interface
OptimismMintableERC20Factory	Proxy	Deploys standard OptimismMintableERC20 tokens that are compatible with either StandardBridge
ProxyAdmin	-	Contract that can upgrade L1 contracts

Contracts deployed to L2

Name	Proxy Type	Description
GasPriceOracle	Proxy	Stores L2 gas price configuration values
L1Block	Proxy	Stores L1 block context information (e.g., latest known L1 block hash)
L2CrossDomainMessenger	Proxy	High-level interface for sending messages to and receiving messages from L1
L2StandardBridge	Proxy	Standardized system for transferring ERC20 tokens to/from L1
L2ToL1MessagePasser	Proxy	Low-level message passing interface
SequencerFeeVault	Proxy	Vault for L2 transaction fees
OptimismMintableERC20Factory	Proxy	Deploys standard OptimismMintableERC20 tokens that are compatible with either StandardBridge
L2ProxyAdmin	-	Contract that can upgrade L2 contracts when sent a transaction from L1

Legacy and deprecated contracts

Name	Location	Proxy Type	Description
AddressManager	L1	-	Legacy upgrade mechanism (unused in Bedrock)
DeployerWhitelist	L2	Proxy	Legacy contract for managing allowed deployers (unused since EVM Equivalence upgrade)
L1BlockNumber	L2	Proxy	Legacy contract for accessing latest known L1 block number, replaced by L1Block

Installation

We export contract ABIs, contract source code, and contract deployment information for this package via npm:

npm install @eth-optimism/contracts-bedrock

Development

Dependencies

We work on this repository with a combination of Hardhat and Foundry.

1. Install node modules with pnpm (v8) and Node.js (16+):

pnpm install

1. Install the correct version of foundry (defined in the .foundryrc file in the root of this repo.

pnpm install:foundry

Build

pnpm build

Tests

pnpm test

Deployment

The smart contracts are deployed using foundry with a hardhat-deploy compatibility layer. When the contracts are deployed, they will write a temp file to disk that can then be formatted into a hardhat-deploy style artifact by calling another script.

Configuration

Create or modify a file <network-name>.json inside of the deploy-config folder. By default, the network name will be selected automatically based on the chainid. Alternatively, the DEPLOYMENT_CONTEXT env var can be used to override the network name. The spec for the deploy config is defined by the deployConfigSpec located inside of the hardhat.config.ts.

Execution

1. Set the env vars ETH_RPC_URL, PRIVATE_KEY and ETHERSCAN_API_KEY if contract verification is desired
2. Deploy the contracts with forge script -vvv scripts/Deploy.s.sol:Deploy --rpc-url $ETH_RPC_URL --broadcast --private-key $PRIVATE_KEY Pass the --verify flag to verify the deployments automatically with Etherscan.
3. Generate the hardhat deploy artifacts with forge script -vvv scripts/Deploy.s.sol:Deploy --sig 'sync()' --rpc-url $ETH_RPC_URL --broadcast --private-key $PRIVATE_KEY

Deploying a single contract

All of the functions for deploying a single contract are public meaning that the --sig argument to forge script can be used to target the deployment of a single contract.

Tools

Layout Locking

We use a system called "layout locking" as a safety mechanism to prevent certain contract variables from being moved to different storage slots accidentally. To lock a contract variable, add it to the layout-lock.json file which has the following format:

{
  "MyContractName": {
    "myVariableName": {
      "slot": 1,
      "offset": 0,
      "length": 32
    }
  }
}

With the above config, the validate-spacers hardhat task will check that we have a contract called MyContractName, that the contract has a variable named myVariableName, and that the variable is in the correct position as defined in the lock file. You should add things to the layout-lock.json file when you want those variables to never change. Layout locking should be used in combination with diffing the .storage-layout file in CI.