Lesson 14: RandomIpfsNft- Different error message displayed on testnet

[ManuWeb3]

Hi all,

I tried to execute safeTransferFrom from a non-onwer address and, as expected, the transaction reverted.

But, the error message that showed up on the testnet UI is different from the one in revert string of the function.

Revert string says "ERC721: caller is not token owner nor approved" but the testnet UI displays below:

Why is that ?

Code snippets below:

safeTransferFrom(3 args)

function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

nested safeTransferFrom(4 args)

function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved");
        _safeTransfer(from, to, tokenId, data);
    }

_isApprovedOrOwner()

function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
    }

[RoboCrypter]

@ManuWeb3 : The error is saying the sender is not approved by the from address!

[ManuWeb3]

@abossofmyself ... But hey, that's exactly the question:

Shouldn't it display the string: ERC721: caller is not token owner nor approved instead of what it actually showed in Red?

The sender is not approved..Right.. So, require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved"); should revert with this string.

What am I missing here ?

[RoboCrypter]

@ManuWeb3 : It is not showing any error as from the contract!

It is just saying in its own that sender is not approved/authorized by from address!

[ManuWeb3]

The owner of NFT is 0x....af8c.
And, I tried to run it with non-owner 0x...90B5 (from address).

So, Goerli testnet's own code is doing some kind of internal check and coming up with its own error (in red) that non-owner 90B5 is not authorized by the owner af8c ?

And, this happens even before it reaches my code require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved"); ?

Is it so ?

[RoboCrypter]

@ManuWeb3 : Yes, that is a plausable explanation because this error is not coming from your contract!

It is from etherscan!

[ManuWeb3]

Noted!! Thanks