[Bug]: Cannot have a buy offer and sell offer at the same time

[viyer28]

Which package is this bug report for?

auction-house

Which Type of Package is this bug report for?

Rust Contract

Issue description

We've built a secondary marketplace for semi-fungible tokens, i.e. SPL tokens linked to the same metadata. A common use case we've seen in the secondary marketplace is to create listings, but still create bids at lower prices to accumulate more of a particular item. Unfortunately, those bids are un-executable because of this particular error in execute_sale: https://github.com/metaplex-foundation/metaplex-program-library/blob/master/auction-house/program/src/execute_sale/mod.rs#L1722-L1724

Steps to reproduce (need two accounts A and B):

1. Create a sell offer for an item using account A.
2. Create a buy offer for that same item using account A.
3. Create a matching sell offer and execute the sale (as two instructions in the same transaction) from account B.

Result:
Error 0x1785 (6021) BuyerATACannotHaveDelegate

• You can experience this yourself on Devnet at https://devnet.glass.xyz/watch/pLeuj4Mj7hiigZwHwwZcRYKxb494XdPF9Co5ZZZaTCa by buying the listing from 5SP9...ZEPj and selling it to V's offer in the 'Offers' tab.

I understand why the Seller's ATA shouldn't have a delegate that's not the auction house in this case, but why shouldn't the Buyer's ATA have a delegate? Is there a way to get around this for this particular use case?

Edit: Another common use case is to create a sell offer and then purchase someone else's sell offer at a lower price. This results in the same issue as both a sell offer and a buy offer are needed for that same item.

Steps to reproduce:

1. Create a sell offer for an item using account A.
2. From account A, create a matching buy offer and execute the sale on account B's item.

Relevant log output

Error: failed to send transaction: Transaction simulation failed: Error processing Instruction 2: custom program error: 0x1785

Priority this issue should have

High (immediate attention needed)

[viyer28]

@samuelvanderwaal @blockiosaurus I believe this has to do with the fact that "Fungible Assets" aka semi-fungible tokens use one token account for all tokens owned by a specific holder.

The issue with the following lines of code in execute_sale is that they don't account for when people have listed some of the other tokens in that token account.

metaplex-program-library/auction-house/program/src/execute_sale/mod.rs

Lines 1633 to 1635 in ba44794

	if seller_rec_acct.delegate.is_some() {
	return Err(AuctionHouseError::SellerATACannotHaveDelegate.into());
	}

metaplex-program-library/auction-house/program/src/execute_sale/mod.rs

Lines 1688 to 1690 in ba44794

	if buyer_rec_acct.delegate.is_some() {
	return Err(AuctionHouseError::BuyerATACannotHaveDelegate.into());
	}

My proposed solution would be to not simply check whether a delegate exists on the account, but if a delegate exists, also look at the delegated_amount with respect to the token_size and amount in the token account.

This is a very important issue for using Auction House with SFTs.

[johnsonchau-bulb]

@viyer28 has there been any updates on this?

[viyer28]

No updates yet!