警告！ 合约执行期间遇到的错误 [已恢复]

Question

1)What can cause this message error to appear while depositing ERC20 on allowance? "Warning! Error encountered during contract execution [Reverted]"

2)Also from what I noticed while debugging it has something to do with 'require(b <= a)' while depositing. I haven't seen it with tokens using 'assert' instead of 'require' for their SafeMath, would using 'assert' display different error message for the same problem? Or I'm just missing something?

Answer 1

What can cause this message error to appear while depositing ERC20 on allowance? "Warning! Error encountered during contract execution [Reverted]"

It depends on the actual contract implementation. Revert happens when a contract produces an invalid opcode, most likely as a result of failed validation in require() , assert() or throws the exception directly using throw() .

Most likely, it's going to fail a validation whether the transaction sender is allowed to send this amount of the owner's tokens, or whether the owner has this amount available.

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Would using 'assert' display different error message for the same problem?

assert() doesn't allow for custom error message.

The "Warning. Error encountered..." is a message from your web3, not the contract itself. It's going to display the same message when the transaction reverts - no matter whether it reverted because of assert() or require() .