SIP-57: Permanent Read-only Proxy for Address Resolver

Simple Summary

A permanent read-only proxy to the latest AddressResolver instance.

Abstract

Create and maintain a read-only proxy to the latest AddressResolver instance. Third party contracts can then reference this proxy in their code and rest assured that thier code will work with future versions of the AddressResolver.

Motivation

Synthetix is a protocol that iterates fairly frequently. Yet we want to provide an immutable avenue for that third party contracts to connect with our infrastructure, even after upgrades.

Specification

To create a minimal version of Proxy, called ReadProxy, that forwards non-mutable calls to the underlying target and returns its results (transacting to mutated functions will fail).

The owner of this ReadProxy will be the ProtocolDAO and is the only one that can change the target of this proxy. The target will change only when a new version of the contract is released.

The ReadProxy will conform to the current IAddressResolver interface, which is:

interface IAddressResolver {

    function getAddress(bytes32 name) external view returns (address);

    // Note ⚠️⚠️⚠️: This is coming in the Altair (v2.22) release of Synthetix
    function getSynth(bytes32 key) external view returns (address);

    function requireAndGetAddress(bytes32 name, string calldata reason) external view returns (address);

}

Rationale

While we could simply reuse the Proxy contract, it's much more powerful than is necessary here, so we propose a simpler and safer read-only version of the proxy for this instance.

Test Cases

• When any view function from AddressResolver is invoked on this ReadProxy instance, it forwards the request to the AddressResolver and returns its response
• When any mutative function call (other than what is in the ReadProxy's ABI directly) is attempted, the transaction will fail
• When the target of ReadProxy changes, it emits a TargetUpdated event.

Implementation

See commit b015b8f5 and corresponding PR #512

Configurable Values (Via SCCP)

(None)

Copyright

Copyright and related rights waived via CC0.