LinkTokenOnMatic.sol

pragma solidity ^0.6.0;


import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.2.0/contracts/token/ERC20/IERC20.sol";

contract LinkTokenOnMatic {
    
    IERC20 public token;
    
    // child chain manager
    address public depositor;
    address public deployer;
    
    // This is the address of deployed & unchanged v4 LinkToken
    constructor(address _token) public {
        token = IERC20(_token);
        require(token.totalSupply() == token.balanceOf(address(this)), "I need to have it all.");
        // child chain manager proxy
        depositor =  0xb5505a6d998549090530911180f38aC5130101c6;
        deployer =  msg.sender;
    }
    
    function updateDepositor(address newDespositor) external {
        require(msg.sender == deployer, "You can't update me");
        depositor = newDespositor;
    }
    
    
    // additional methods needed for enabling cross chain asset transfer
    
    function deposit(address user, bytes calldata depositData) external {
        require(msg.sender == depositor, "Only ChildChainManager can deposit");
        require(user != address(0), "Not a valid address");
        
        uint256 amount = abi.decode(depositData, (uint256));
        token.transfer(user, amount);
    }
    
    function withdraw(uint256 amount) external {
        token.transferFrom(msg.sender, address(this), amount);
    }
}

Yes we can do this 👍

Are you also emitting Transfer event from withdraw ?

I think Openzeppelin has it. Still just to confirm.

Yes, the Transfer event is emitted, but from the LinkToken not LinkTokenOnMatic (this) contract.

Also, the Transfer will not be from 0x0 but from the address of LinkTokenOnMatic holding contract.

One more thing, the withdraw function will need to be a 2-step in this case. The transferFrom will first need to be approved by the token holder.

Well not associating address 0x0, in events will cause issue, and it'll not get included in checkpoint. That's the idea while check pointing. Can you fix that ?

@itzmeanjan consider this proposal and discussion deprecated. I am working on a new implementation that will hopefully be ready for a test run in a day or two.

You can take a peek here.

Alright 👍