OptimismPortal Interop

Table of Contents

Overview

The OptimismPortal contract is integrated with the ETHLockbox for managing unified ETH liquidity. This liquidity consists of every ETH balance migrated from each OptimismPortal when joining the op-governed dependency set.

It is possible to upgrade to this version without being part of the op-governed dependency set. In this case, the corresponding chain would need to deploy and manage its own ETHLockbox.

Integrating ETHLockbox

The integration with the ETHLockbox involves locking ETH when executing deposit transactions and unlocking ETH when finalizing withdrawal transactions, without altering other aspects of the current OptimismPortal implementation.

Interface and properties

ETH Management

migrateLiquidity

Migrates the ETH liquidity to the ETHLockbox. This function will only be called once by the ProxyAdmin owner when updating the OptimismPortal contract.

function migrateLiquidity() external;
  • MUST only be callable by the ProxyAdmin owner
  • MUST transfer all ETH balance to the ETHLockbox
  • MUST emit an ETHMigrated event with the amount transferred

Internal ETH Functions

_lockETH

Called during deposit transactions to handle ETH locking.

function _lockETH() internal;
  • MUST be invoked during depositTransaction when there is ETH value
  • MUST lock any ETH value in the ETHLockbox

_unlockETH

Called during withdrawal finalization to handle ETH unlocking.

function _unlockETH(uint256 _amount) internal;
  • MUST be invoked during withdrawal finalization when there is ETH value
  • MUST unlock the withdrawal value from the ETHLockbox
  • MUST revert if withdrawal target is the ETHLockbox

Events

ETHMigrated

MUST be triggered when the ETH liquidity is migrated to the ETHLockbox.

event ETHMigrated(uint256 amount);

Invariants

  • Deposits MUST lock the ETH in the ETHLockbox

  • Withdrawals MUST unlock the ETH from the ETHLockbox and forward it to the withdrawal target

  • The contract MUST NOT hold any ETH balance from deposits or withdrawals

  • The contract MUST be able to handle zero ETH value operations

  • The contract MUST NOT allow withdrawals to target the ETHLockbox address