Wrong address rertun when I call ownerof with delegatecall

Question

I am trying to call the function "ownerof" of a contract but it return me something like that : 0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000020000000000000000000000000bc641d0c1acc8f85bb53aceade03bbc58de693d1

The function is :

    function updateRaceLeaderboard(
    uint256 raceID,
    uint256[] memory _leaderboard
) public onlyOwner returns (bytes memory addr) {
    RaceleaderBoard[raceID] = _leaderboard;
   
    address contractAddress = 0x80AFf21544b6670fCfD813134C83Bb340307c453;
    (bool success, bytes memory returndata) = contractAddress.call(
        abi.encodeWithSignature("ownerOf(uint256)", 0)
    );
    return returndata;
}

I call it like that:

    dev = accounts.add(config["wallets"]["from_key"])
print("Working on " + network.show_active())
trx = race.updateRaceLeaderboard(
    0,
    [0],
    {"from": dev},
)

The ownerOf(uint256) function is in a different contract at :

https://mumbai.polygonscan.com/address/0x80AFf21544b6670fCfD813134C83Bb340307c453#readContract

The success bool return True

Do you know how Can I receive a correct address ?

Answer 1

you need to decode the return data with abi.decode(returndata, (address))

Answer 2

In the comments you said it didn't succeed then it is not return an address but an error message

The error could be interpreted as

0x
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000084
08c379a0
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000029
4552433732313a206f776e657220717565...

The 08c379a0 is a error signature Error(string)

Decoding the string messgae 4552433732313a206f776e657220717565 it gives

ERC721: owner que

My guess is that corresponds to

function ownerOf(uint256 tokenId) public view virtual override returns (address) {
    return _tokenOwners.get(tokenId, "ERC721: owner query for nonexistent token");
}

My second guess is that you shouldn't be using delegatecall, but call or staticcall instead.

---

Example how to parse the returned data

(bool success, bytes memory returndata) = contractAddress.call(
    abi.encodeWithSignature("ownerOf(uint256)", 0)
);


if (success) {
    (address owner) = abi.decode(returndata, (address));
    return owner;
}