Trying to use _transfer inside an OpenZep implementation

Support
1

I wrote a contract that extends OpenZep’s ERC20PresetFixedSupply contract. My goal is to add a function that sends tokens to a hardcoded address. I tried to add this function transferToVitalik but it is not working:

// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.4;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.1.0/contracts/token/ERC20/presets/ERC20PresetFixedSupply.sol";

contract TESTToken is ERC20PresetFixedSupply("TestCoin", "TEST", 10**24, msg.sender) {
    function transferToVitalik() public {
        _transfer(msg.sender, address(0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B), uint256(500000000000000000000000));
    }
}

I deployed via Remix and tried to use the function, but Metamask pops up to do the transaction and the value is 0.

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I am confused on why this does not work cause I am just wrapping the _transfer method and hardcoding the arguments. I tried also wrapped transfer and transferFrom instead and I get the same behavior.

2

The “value” of 0 corresponds to the amount of ETH sent in the transaction. Tokens do not count as value in this sense.

3

But if I interact with the native transfer method, it won’t show 0 in metamask, it will instead correctly reflect the tokens I want to send.

4

Ok sorry I wasn’t familiar with that.

In that case, it must be recognizing the standard transfer(address,uint) function signature and showing the uint argument as the value. I doubt Metamask is simulating the transaction to detect that internally a transfer will be performed.

So if you want Metamask to display the value you have to use ERC20’s built in transfer function.

5

I tried both _transfer and transfer and I get the same result. Metamask just shows 0 and if I do the transaction, it indeed does not send anything.

6

You could try by just pasting that code snippet into remix.

7

Ok retried it. It actually does work if I use transfer within my transferToVitalik function. It actually sends the tokens, but it still does not show in Metamask. Is this some limitation of Metamask?

8

Yeah looks like Metamask will only show the value if the function name is transfer or transferFrom