require(msg.sender == owner(), 'not owner') throwing exception although msg.sender equals owner() when inspected in event

Question

I am new to solidity so please excuse if the question is to easy but i didn't find any relating thread.

I have a marketplace contract which inherits from openzeppelins ownable.sol and i want to check access to the listNFT function to only be done by the owner of the contract. I tried the onlyOwner modifier which didn't work raising 'the caller not owner' error. Then i tried to understand the exact values of msg.sender and owner() and build my own event to track the values of msg.sender and owner. You can see the relevant code here.

    # Event to keep track of owner and caller
    event FunctionCall(
        address caller,
        address owner
    );

    // List the NFT on the marketplace
    function listNft( uint256 _tokenId, uint256 _price) public payable nonReentrant {

        # Emit event to inspect caller and owner
        emit FunctionCall(msg.sender ,owner());

        require(_price > 100, "Price must be at least 100 wei");

        # This line doesn't let me through and evaluates to false
        # require(msg.sender == owner(), "Must be owner");

      ...more code
    }

When i call the contract without the require owner statement I can inspect the events on polygonscan which gives the following

Polygonscan event

The event shows that msg.sender and owner are the same address, how can the require statement afterwards evaluate to false?

I tested casting msg.sender and owner() to address(msg.sender) and address(owner()) but it didn't work. What am i missing?

Thanks in advance for any help!

Answer 1

I found the answer, thank you for your comments!

There was a problem with the signing methods. Earlier I signed transactions manually like this with Web3.py

  transaction = contract.functions.transferFrom(w3.toChecksumAddress(<PublicKey>),w3.toChecksumAddress(to),  token_id).buildTransaction({
        'from': acct.address,
        'nonce': w3.eth.get_transaction_count(acct.address),
    })
    gas = w3.eth.estimate_gas(transaction)
    transaction.update({'gas': int(gas*1.5)})
    signed_transaction = w3.eth.account.sign_transaction(transaction, private_key=<PRIVKEY>)
    tx_hash = w3.eth.send_raw_transaction(signed_transaction.rawTransaction)
    tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)

After switching to the.transact() method and construct_sign_and_send_raw_middleware () from web3.py everything works. I am still stumped that the event gave out the correct msg.sender on polygonscan but as long as everything works I won't complain:)