可升級合約

使用 delegate call 搭配 solidity 的 fallback function 傳入 calldata。呼叫時會呼叫 proxy contract 然後指向實際的邏輯合約。

Upgrading smart contracts - OpenZeppelin Docs

HardHat 範例：

https://blog.logrocket.com/using-uups-proxy-pattern-upgrade-smart-contracts/

原理

Upgradeable proxy contract from scratchMedium

DelegateCall 用法

contract test {
    uint256 public result;
    function add(uint256 a, uint256 b) public returns (uint256) {
        result = a + b;
        return result;
    }
}

contract test1 {
    function addValues(address test, uint256 a, uint256 b) public returns (uint256) {
        (bool success, bytes memory result) = test.delegatecall(abi.encodeWithSignature("add(uint256,uint256)", a, b));
        return abi.decode(result, (uint256));
    }
}

Call v.s delegateCall:

https://ethereum.stackexchange.com/a/3672/30691

encodeWithSignature v.s encodeWithSelector: https://ethereum.stackexchange.com/q/91826/30691