Proxies & Upgradeable Contracts — Hands-on lab

Practice the failure modes Intentionally reorder a variable in tests to see how storage breaks. Practice an unauthorized upgrade and make sure it fails. Rehearse your upgrade script on testnet and verify on an explorer.

Cryptography is about how to maintain control over information.

— Shafi Goldwasser

Observability Emit upgrade events, log implementation addresses, and keep a changelog. Verify proxiableUUID for UUPS to avoid proxy bricking.

Runbooks Write down the exact CLI steps to upgrade, who signs, and how to verify storage afterward. Include rollback steps and thresholds for pausing.

contract Box is Initializable, UUPSUpgradeable, OwnableUpgradeable {
    uint256 public value;

    function initialize(uint256 v) public initializer {
        __Ownable_init();
        __UUPSUpgradeable_init();
        value = v;
    }

    function _authorizeUpgrade(address newImpl) internal override onlyOwner {}

    function setValue(uint256 v) external onlyOwner { value = v; }
}

// test storage append-only:
// V2 adds: uint256 public extra;
// ensure reordering fails in tests.