Can I change the comments in a contract and still pass Etherscan verification?

Question

Suppose that you have a contract, someone audited it, and you would like to use that specific version for compilation and deployment to Ethereum.

Now, you want to verify the source code on Etherscan, but say that you want to modify one or more comments before you verify the source code for the first time. Would Etherscan still be able to pass the verification or not?

I know that changing just one character in a contract changes the metadata hash, but I'm not sure whether Etherscan checks for that.

Answer 1

Etherscan only compares the bytecode of the submitted contract to the bytecode of the deployed contract (excluding the metadata hash). So you can change any comments and the source code will still be verified by Etherscan.

Source of this information is my own findings while developing truffle-plugin-verify. I have verified many contracts where the comments in the submitted contract did not match the comments in the deployed contracts.

Answer 2

If the bytecode is identical, and it matches a previous implementation, you won't be able to check it again. You have to ensure that the bytecode is different, or compile via another version.