Upgrade Setup #

We will use the UpgradeBeacon pattern to implement three upgradable contract types: Home, Replica, and GovernanceRouter.

Each upgradable contract will have:

• Proxy
  • the permanent address of the contract that external entities interact with
  • holds the storage of the contract
  • uses the logic specified by Implementation
  • uses delegatecall to forward contract calls from Proxy → UpgradeBeacon → Implementation
• UpgradeBeacon
  • stores the (mutable) address of the Implementation
  • forwards delegatecalls to the Implementation
  • accepts new Implementation addresses from its Controller (thereby performing upgrades for all Proxies)
• Implementation
  • specifies the logic of the contract
  • code is the same as a normal, non-upgradable contract implementation (though it should use upgrade-safe storage)

Each of the three UpgradeBeacon contracts will share a the same Controller — the contract with the power to perform upgrades.

The Controller contract will have two roles: controller and saver.

• controller
  • is a transferrable role that should be performing upgrades in almost every case.
  • will be set to the GovernanceRouter Proxy, so that the Governance xApp ultimately controls the upgrades of the entire system. Note that this creates a circular dependency which makes upgrades of the GovernanceRouter Implementation particularly sensitive.
• saver
  • is a transferrable(?) role that is responsible for recovering the system in a catastrophic failure case. Actions performed by the saver will be subject to a timelock enforced by the Controller contract.
  • will be set to a multisig contract where the signatories are a set of known / trusted community members. the signatories for the saver multisig be the same on every chain

Diagrams #