safeTransferFrom of ERC721 not working when transfering NFT to a safe address

Question

I was trying to transfer an NFT using ERC721's safeTransferFrom method from my gnosis safe to another gnosis safe address but while executing the transaction I am getting -

Error: cannot estimate gas; transaction may fail or may require manual gas limit (error={"code":3,"message":"execution reverted: GS013","data":"0x08c379a0000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000054753303133000000000000000000000000000000000000000000000000000000"}, method="estimateGas", transaction={"from":"0x3c7c3487d6782266059193C2593D6a2f9aC43989","to":"0x01d0a2c2fE8d8B08B3Df890cA5dBE4aBCE1Fa642","data":"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","accessList":null}, code=UNPREDICTABLE_GAS_LIMIT, version=providers/5.5.3)
{
  reason: 'cannot estimate gas; transaction may fail or may require manual gas limit',
  code: 'UNPREDICTABLE_GAS_LIMIT',
  error: {
    code: 3,
    message: 'execution reverted: GS013',
    data: '0x08c379a0000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000054753303133000000000000000000000000000000000000000000000000000000'
  },
  method: 'estimateGas',
  transaction: {
    from: '0x3c7c3487d6782266059193C2593D6a2f9aC43989',
    to: '0x01d0a2c2fE8d8B08B3Df890cA5dBE4aBCE1Fa642',
    data: '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',
    accessList: null
  }
}

On executing the same transaction with a different target address, i.e, my Metamask wallet address(EOA) it is working fine. Also when I tried transferring the NFT from my Metamask wallet to gnosis safe address via Opensea UI(Profile -> NFT -> Transfer) then also it is not working but working when the target address is my Metamask wallet address. So, I further checked and found Opensea UI also uses safeTransferFrom method to transfer NFTs.

Now, another thing I found is that transferring NFT to a safe address works fine with transferFrom method of ERC721.

So, not sure but I think the reason could be, as mentioned here:

If the target address is a contract, it must implement IERC721Receiver.onERC721Received, which is called upon a safe transfer, and return the magic value bytes4(keccak256("onERC721Received(address,address,uint256,bytes)")); otherwise, the transfer is reverted.

This is the decoded data of the transaction which was failing.

• Why safeTransferFrom is not working when target address is gnosis safe?
• Is it fine to use transferFrom method as safeTransferFrom is not working?

Edit: It is a bug in the gnosis SDK and an issue exist here for this. Once gnosis team fix this, I will mark this question as resolved.

Answer 1

A fallback handler that allows to handle NFTs is missing in the recipient Safe.

Fixed here how to add a fallback handler to a given Safe and adding a default fallback handler to newly deployed Safes: https://github.com/safe-global/safe-core-sdk/issues/262

Answer 2

I will refer to OpenZeppelin's ERC721 implementation throughout my answer.

Why safeTransferFrom is not working when target address is gnosis safe?

Because the Gnosis Safe contract does not implement the IERC721Receiver interface, which must be implemented by smart contract that receive NFTs if you want to use the safeTransferFrom function.

To quote the original spec of ERC721, "a wallet/broker/auction application MUST implement the wallet interface if it will accept safe transfers."

Is it fine to use transferFrom method as safeTransferFrom is not working?

Yes, because Gnosis Safe is a multi-signature wallet that can execute any function from any third-party smart contract.

The rationale in the original spec of ERC721 was to prevent accidental transfers to contracts that can no longer transfer the NFT.

That is not a risk with Gnosis Safe. If you get enough signatures, you can choose to transfer the NFT by calling the NFT contract.