prevalidation

[nicolasochem]

Relay

The relay receives operations and keeps them until they are included. But they could become no longer valid, for example:

• user got tired of waiting and used regular mempool
• user tries to buy an NFT that has already been purchased by someone else

Tezos has a "preapply" endoint which lets you check whether the operation would be applied.

I think preapply does:

• a precheck and/or
• a prevalidation of the operation.

As a result, if this fails, we should remove the operation from the relay's mempool.

Endpoint

The endpoint should also prevalidate the current winner of the auction, before submitting it, otherwise the baker won't include the operation and the flashbaker won't earn the fee.