Can we override the private variable in base contract?

Question

Background: I'm using an opezeppellin Erc20 contract. but i want to use it for minimal proxy pattern(eip-1167). so for that reason i cannot use constructor and have to use the initialize method. Now I'm unsure how to translate this constructor into initialize method.

constructor(uint256 initial_supply) ERC20("Solderse", "SOLD") {
        _mint(msg.sender, initial_supply * 10 ** uint256(decimals()));
    }

so I opt out to hack around which is as follows.

string private _myName;
string private _mySymbol;
bool private _initialized;

constructor() ERC20("", "") {
    _initialized = false;
}

function initialize(string memory _name, string memory _symbol, uint256 initial_supply) external {
    require(!_initialized, "Already initialized"); // Ensure it's not initialized yet
    _myName = _name;
    _mySymbol = _symbol;
    _initialized = true;
    _mint(msg.sender, initial_supply * 10 ** uint256(decimals()));
}

Here I'm initializing my child contract with blank ERC20 constructor to silent off the errors and using an initialize method where I'm setting a name and symbol.

Now another issue arises as in Erc20 implementation the name and symbol are private variables so I cannot change them so I opt in with another hack which is to create two override public function who can change the name and symbol so I made these two functions.

function name() public view override returns (string memory) {
    return _myName;
}

function symbol() public view override returns (string memory) {
    return _mySymbol;
}

And I can write tests to check the name and symbol are returning the values correctly but these hacks are not what I'm looking for as far as i know ERC20 storage values have not changed at any case and i find it not very much sophisticated. so basically my question is

Can we override the private variables from child Contract or How can I implement a basic er20 in minimal proxy pattern?

Answer 1

I think you should be able to use https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable/blob/master/contracts/token/ERC20/ERC20Upgradeable.sol together with the minimal proxy

Answer 2

You can use Openzeppelin's upgradeable set of contracts for this.

https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable

The trick here is, each upgradeable contract that you inherit dont have a constructor either, but an _init function (and also an __init_unchained)

So, for an ERC20, inside your inititialize() function you should have __ERC20_init(name, symbol)

You can see an example for an ERC20 in this article

https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable

Hope it helps