Stateless airdrops

[kumaryash90]

No description provided.

[nkrishang]

Re: this native token amount check: https://github.com/thirdweb-dev/contracts/blob/yash/stateless-airdrops/contracts/airdrop/AirdropERC20.sol#L119C9-L119C82

This check happens outside the for loop, however we should try to revert as early as possible, since the for loop is likely to have many runs (due to many recipients). What about this pattern:

uint256 msgValue = msg.value;
uint256 nativeTokenAmount = 0;
bool insufficientValue = false;

for(uint256 i = 0; i < len; ) {
   // .. whatever logic
  
    if (_tokenAddress == CurrencyTransferLib.NATIVE_TOKEN) {
        nativeTokenAmount += _contents[i].amount;
       
        if(nativeTokenAmount > msgValue) {
            insufficientValue = true;
            break;
        }
    }
}

require(!insufficientValue && msgValue == nativeTokenAmount);

[nkrishang]

Re: this native token amount check: https://github.com/thirdweb-dev/contracts/blob/yash/stateless-airdrops/contracts/airdrop/AirdropERC20.sol#L119C9-L119C82

This check happens outside the for loop, however we should try to revert as early as possible, since the for loop is likely to have many runs (due to many recipients). What about this pattern:

uint256 msgValue = msg.value;
uint256 nativeTokenAmount = 0;
bool insufficientValue = false;

for(uint256 i = 0; i < len; ) {
   // .. whatever logic
  
    if (_tokenAddress == CurrencyTransferLib.NATIVE_TOKEN) {
        nativeTokenAmount += _contents[i].amount;
       
        if(nativeTokenAmount > msgValue) {
            insufficientValue = true;
            break;
        }
    }
}

require(!insufficientValue && msgValue == nativeTokenAmount);

To clarify, the break should happen before the _transferCurrencyWithReturnVal, and not after.

This is because if the msg.value sent in the airdrop call is truly less than the cumulative nativeTokenValue, then at some point, _transferCurrencyWithReturnVal will start returning false for native token transfers. In such a case, we want to revert as soon as possible, and not spend the gas to perform the remaining for loop runs, since the function is going to revert anyway after the loop ends.

[nkrishang]

Let's not inherit Ownable in the AirdropERCxxx contracts; the presence of Permissions is sufficient.