Forgotten Runes Warrior Guild contest - plotchy's results

Be cautious when trusting gas estimation services for issueRefunds()

Trusting wallets to estimate gas on issueRefunds() is likely to fail. It's trivial to trick these services using any type of 'randomness'. See below for a simple example that will cause all major gas estimators to return a wrong estimate.

Lettting you know to save you from what could be failed refund transactions!

contract SneakyRefundee {

    fallback() external payable {
        if (block.number % 2 == 0) {
            revert();
        } else {
            while (gasleft() > uint(1000)) {}
            return;
        }
    }
}