Known Limitations
Payment Processor was designed to maximize safety and efficency while enforcing creator-defined royalties. As a result, there are certain intentional limitations documented below that creators should be aware of.
Push Payment Splitters Are Not Supported
Push Payment Splitters are smart contracts that receive native token funds, split and redistribute them to one or more addresses within the same transaction they are received. Payment Processor limits the amount of gas that a payment recipient can utilize to 8,000 gas units which is not enough to operate a Push Payment Splitter.
Justification:
- Security - Forwarding of all available gas allows for recipients of transfers to execute additional, potentially malicious, logic.
- Push Payments Are An Anti-pattern - The forwarding of native tokens to many destinations in a single transaction has long been considered an anti-pattern. Any one of the recipients could be a re-entrant attacker, or a destination could intentionally revert to grief all the other destinations and DoS a transaction.
- Fairness - Without a gas limit, a push payment splitter could be used to do an arbitrary number of splits. We strongly believe it is unfair to the order takers for them to pay an additional ~10K gas units per split destination with an unbounded limit on the number of destinations. If all transaction gas is forwarded with a payment to a push payment splitter with ten recipients the average transaction cost would double. This is not good for traders executing orders and not efficient for the blockchain.
Recommendations for creators: Use an OpenZeppelin pull payment splitter as your royalty recipient.
It is audited and easy to deploy: OpenZeppelin PaymentSplitter
Batch Listings And Transfers Are Not Supported
Batch listings and transfers have been used to steal millions of dollars worth of NFTs in single transactions from one errant click by a token owner. Payment Processor was intentionally designed to require a signature on each item being listed to provide more secure trading infrastructure. Order takers may still execute orders in bulk.