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 transferring 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

Contributing

For all information about working on and contributing to Optimism's smart contracts, please see CONTRIBUTING.md

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.

The addresses in the deployments directory will be read into the script based on the backend's chain id. To manually define the set of addresses used in the script, set the CONTRACT_ADDRESSES_PATH env var to a path on the local filesystem that points to a JSON file full of key value pairs where the keys are names of contracts and the values are addresses. This works well with the JSON files in superchain-ops.

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

Before deploying the contracts, you can verify the state diff produced by the deploy script using the runWithStateDiff() function signature which produces the outputs inside snapshots/state-diff/. Run the deployment with state diffs by executing: forge script -vvv scripts/Deploy.s.sol:Deploy --sig 'runWithStateDiff()' --rpc-url $ETH_RPC_URL --broadcast --private-key $PRIVATE_KEY.

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.

Test Setup

The Solidity unit tests use the same codepaths to set up state that are used in production. The same L1 deploy script is used to deploy the L1 contracts for the in memory tests and the L2 state is set up using the same L2 genesis generation code that is used for production and then loaded into foundry via the vm.loadAllocs cheatcode. This helps to reduce the overhead of maintaining multiple ways to set up the state as well as give additional coverage to the "actual" way that the contracts are deployed.

The L1 contract addresses are held in deployments/hardhat/.deploy and the L2 test state is held in a .testdata directory. The L1 addresses are used to create the L2 state and it is possible for stale addresses to be pulled into the L2 state, causing tests to fail. Stale addresses may happen if the order of the L1 deployments happen differently since some contracts are deployed using CREATE. Run pnpm clean and rerun the tests if they are failing for an unknown reason.

Static Analysis

contracts-bedrock uses slither as its primary static analysis tool. When opening a pr that includes changes to contracts-bedrock, you should verify that slither did not detect any new issues by running pnpm slither:check.

If there are new issues, you should triage them. Run pnpm slither:triage to step through findings. You should carefully walk through these findings, specifying which to triage/ignore (default is to keep all, outputting them into slither-report.json). Findings can be triaged into slither.db.json or kept in the slither-report.json. You should triage issues with extreme care and security sign-off.

After issues are triaged, or an updated slither report is generated, make sure to check in your changes to git. Once checked in, the changes can be verified by running pnpm slither:check. This will fail if there are issues missing from the slither-report.json that are not triaged into slither.db.json.