NFT Lesson 17: FlipMoodNFT Interactions error

[mikechaban]

Hello there

I am trying to get an additional interaction that is not covered in the lessons to work. After successfully running the MintMoodNFT script on a forked Sepolia chain, I can't run the FlipMoodNFT one. It doesn't even seem like I get a definite error. Here is the error from my terminal

Then there are some traces and the revert error

I tried cleaning the project with forge clean and deleting the cache directory. I want this script to be a programmatic way to interact with the contract.

contract FlipMoodNFT is Script {
    uint256 public constant TOKEN_ID_TO_FLIP = 0;

    function run() external {
        address mostRecentlyDeployedMoodNft = DevOpsTools.get_most_recent_deployment("MoodNFT", block.chainid);
        flipMoodOnContract(mostRecentlyDeployedMoodNft);
    }

    function flipMoodOnContract(address moodNftAddress) public {
        vm.startBroadcast();
        MoodNFT(moodNftAddress).flipMood(TOKEN_ID_TO_FLIP);
        vm.stopBroadcast();
    }
}

You can find my repo here

And the script file here

If someone knows how to fix this please let me know

Thank you in advance ❤️

[EngrPips]

Hello @mikechaban, What happens if you run an actual sepolia chain and not a forked chain?

[mikechaban]

I assume my contract starts with tokenId of 0 cause I haven't specified it anywhere. I seem to have confirmed this by importing my NFT into Metamask.

I thought the script creates a new contract every time. Turns out it's been reusing the same 0x3FD7... contract for several times. You can view it on Etherscan

https://sepolia.etherscan.io/address/0x3FD738Fc27ee9B05F94dc36D8aA1379E3cBBb951

After your response, I checked and noticed there is no transaction other than the contract creation. It means the NFT was not actually minted. The command I was running didn't contain my private key so I included it and the mint transaction appeared on Etherscan.

However, I'm still struggling with the FlipMood interaction. The error I get in the console refers to the flipMood function from MoodNFT contract. More specifically, the flipMood(0).

I believe the problem is that even though the address IS the owner of the NFT, the address is not "approved", so I'm facing an issue in this part

[mikechaban]

@EngrPips
I can't say I found the solution, but I found a way to make it work without the approval. I simply got rid of the part highlighted above, created a new contract instance, minted the NFT, and then flipped the mood.

https://sepolia.etherscan.io/address/0x02f0ebac448facc737529f41a1b22cc7f959144e

https://testnets.opensea.io/assets/sepolia/0x02F0ebAc448FacC737529f41a1b22cc7f959144e/0

Does getting rid of this part compromise the security of the contract in terms of confirming exclusively the owner as the address that's able to flip the mood? Based on the code, I can see that only the owner of the token is the one who can flip the mood, so why do we need the first getApproved part from OpenZeppelin's ERC721?

[EngrPips]

Please show your FlipMood script maybe seeing that can help us make sense of this situation.

[EngrPips]

The token can be flipped by the owner or by any other address the owner has approved. Why not just call the FlipMood function with the private key that minted the token instead of removing that check?

[LordAdhaar]

Your transaction might be failing on Sepolia because you haven't properly specified the account or private key. The contract likely can't identify the msg.sender, which is preventing the mood from being flipped. Without clear sender authentication, the transaction won't execute as expected.

Also use --broadcast when you do sign the transaction
You can use environment variables or add --interactives 1 to the command and it will prompt you to enter the private key and just copy paste that from metamask

[EngrPips]

Interesting.

[mikechaban]

The token can be flipped by the owner or by any other address the owner has approved. Why not just call the FlipMood function with the private key that minted the token instead of removing that check?

That makes sense now, I didn't realize that the line is there to ensure an approved person can flip as well.

Looks like I forgot to specify the private key and the --broadcast flag when running commands. Thanks a lot for the help.

[EngrPips]

Awesome, keep crushing it.