TLaaS (LEX) — Proxy Upgradability Patterns: Delegate-Call Proxies for Contract Upgrades

1. Purpose

Define safe, governance‑controlled contract upgrade mechanisms for TLaaS (LEX) components (e.g., LicenseMarketplace, PaymentOrchestrator, RoyaltyRoutingEngine). Upgrades must preserve storage layout, enforce role‑gated authorization, emit auditable events, and integrate with TLAAS (DLA) and DAL controls. Primary patterns: EIP‑1967 Transparent, UUPS (ERC‑1822), and Beacon. Non‑proxy patterns (EIP‑1167 minimal clones) are covered for factory deployments.

2. Design Principles

• Deterministic Storage: Strict layout discipline;
• Least Privilege: Only a governance executor (timelock + Safe) may authorize upgrades.
• Explicit Initializers: No constructors in logic contracts; use
• Upgrade Simulation: Pre‑deploy storage diff checks; rollback testing; dry‑run on fork.
• Observability: Emit

3. Pattern Selection

• UUPS (ERC‑1822): Preferred for app contracts; lower gas; upgrade code in implementation with
• Transparent (EIP‑1967): Useful where an
• Beacon: Many proxies share a single implementation pointer; suitable for mass upgrades of homogeneous instances.
• Clones (EIP‑1167): For factories minting many lightweight instances; pair with Beacon for bulk logic updates.

4. Storage Layout Discipline

• Append‑only storage; never change order or type of existing fields.
• Reserve
• Track layout with

Example Layout Manifest (snippet)

{
  "contracts/PaymentOrchestrator.sol:PaymentOrchestrator": {
    "storage": [
      {"label":"WETH","type":"t_address","slot":"0","offset":0},
      {"label":"lexTreasury","type":"t_address","slot":"1","offset":0}
    ]
  }
}

5. UUPS Implementation (Recommended)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.24;

import {Initializable} from "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import {UUPSUpgradeable} from "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";
import {AccessControlUpgradeable} from "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";

contract PaymentOrchestratorV1 is Initializable, UUPSUpgradeable, AccessControlUpgradeable {
    bytes32 public constant GOVERNANCE_ROLE = keccak256("GOVERNANCE_ROLE");

    address public lexTreasury;
    address public router;

    uint256[48] private __gap; // storage gap

    function initialize(address _treasury, address _router) public initializer {
        __AccessControl_init();
        __UUPSUpgradeable_init();
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _grantRole(GOVERNANCE_ROLE, msg.sender);
        lexTreasury = _treasury;
        router = _router;
    }

    function _authorizeUpgrade(address newImplementation) internal override onlyRole(GOVERNANCE_ROLE) {}
}

Proxy Deployment (UUPS)

// deploy_uups.ts
import { ethers, upgrades } from "hardhat";

async function main() {
  const Impl = await ethers.getContractFactory("PaymentOrchestratorV1");
  const proxy = await upgrades.deployProxy(Impl, [process.env.TREASURY!, process.env.ROUTER!], { kind: 'uups' });
  await proxy.waitForDeployment();
  console.log('Proxy:', await proxy.getAddress());
}
main();

Upgrade Execution

// upgrade_uups.ts
import { ethers, upgrades } from "hardhat";

async function main() {
  const proxyAddr = process.env.PROXY!;
  const NewImpl = await ethers.getContractFactory("PaymentOrchestratorV2");
  await upgrades.upgradeProxy(proxyAddr, NewImpl);
}
main();

6. Transparent Proxy (EIP‑1967) Variant

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import {TransparentUpgradeableProxy} from "@openzeppelin/contracts/proxy/transparent/TransparentUpgradeableProxy.sol";
import {ProxyAdmin} from "@openzeppelin/contracts/proxy/transparent/ProxyAdmin.sol";

contract Deploy1967 {
    ProxyAdmin public admin;
    TransparentUpgradeableProxy public proxy;

    constructor(address impl, bytes memory initData) {
        admin = new ProxyAdmin();
        proxy = new TransparentUpgradeableProxy(impl, address(admin), initData);
    }
}

Admin Upgrade Call

// admin_upgrade.ts
import { ethers } from 'hardhat';
import { ProxyAdmin } from '../typechain';

async function main(){
  const admin = await ethers.getContractAt('ProxyAdmin', process.env.ADMIN!);
  await admin.upgradeAndCall(process.env.PROXY!, process.env.NEW_IMPL!, '0x');
}
main();

7. Beacon Pattern

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import {UpgradeableBeacon} from "@openzeppelin/contracts/proxy/beacon/UpgradeableBeacon.sol";
import {BeaconProxy} from "@openzeppelin/contracts/proxy/beacon/BeaconProxy.sol";

contract BeaconDeployer {
    UpgradeableBeacon public beacon;

    constructor(address impl, address owner){
        beacon = new UpgradeableBeacon(impl);
        beacon.transferOwnership(owner);
    }

    function newInstance(bytes memory initData) external returns (address){
        BeaconProxy p = new BeaconProxy(address(beacon), initData);
        return address(p);
    }
}

8. Initialization & Versioning

• Use
• Guard against re‑init with
• Store

Versioned Initializer

function initializeV2(/* new params */) public reinitializer(2) {
    // add new fields safely
}

9. Authorization & Governance Integration

• UUPS
• Transparent/Beacon upgrades restricted to
• Record DAL proposal id in an on‑chain registry before allowing

Timelock Gate (concept)

interface ITimelock { function isOperationReady(bytes32 id) external view returns (bool); }

contract UpgradeGate {
    ITimelock public timelock;
    mapping(address => bytes32) public requiredProposal; // proxy => proposalId
    function canUpgrade(address proxy) external view returns (bool) {
        return timelock.isOperationReady(requiredProposal[proxy]);
    }
}

10. Safety Checks & Tooling

• Storage Layout Diff:
• Rollback Test: upgrade → call → upgrade back; verify state and behavior unchanged.
• Access Controls: fuzz tests on
• Pause Before Upgrade: optional emergency pause via

Hardhat Test (excerpt)

it('prevents non-governance upgrade', async () => {
  const v2 = await ethers.getContractFactory('PaymentOrchestratorV2');
  await expect(upgrades.upgradeProxy(proxy.address, v2.connect(attacker))).to.be.reverted;
});

11. Diamond Pattern (Optional)

If modular facets are needed (e.g., Marketplace facets), use EIP‑2535 with caution: higher complexity, selector collisions, and tooling overhead. Prefer UUPS for simpler governance.

12. Clones & Factories

For per‑issuer SublicenseModule instances:

• Deploy EIP‑1167 minimal proxies from a factory.
• Optionally point clones to a Beacon for coordinated upgrades.

Factory (EIP‑1167)

library Clones { function clone(address impl) internal returns (address instance); }

contract SublicenseFactory {
    address public impl;
    event Instance(address indexed owner, address proxy);
    constructor(address _impl){ impl = _impl; }
    function create(address owner, bytes memory init) external returns (address p){
        p = Clones.clone(impl);
        (bool ok,) = p.call(init); require(ok, 'init failed');
        emit Instance(owner, p);
    }
}

13. Operational Runbook

• Pre‑Upgrade:
• Freeze window announced; submit DAL proposal; generate storage manifest; run fuzz/invariants.
• Execute:
• Timelock executes upgrade;
• Post‑Upgrade:
• Monitor key metrics; run sanity txs; publish release notes (SBOM, audit delta, storage diff).

14. Acceptance Criteria

• Storage layout unchanged for existing slots; gaps preserved.
• Only governance executor can upgrade; DAL gate enforced.
• Rollback test passes; invariants hold; no critical static‑analysis findings.
• All proxies emit expected events with implementation address fingerprints.

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