introduce min change target

This commit is contained in:
Michael Sutton 2024-05-09 11:24:43 +03:00
parent f41dc7fa0b
commit 3dbafb62db

View File

@ -14,6 +14,11 @@ import (
// TODO: Implement a better fee estimation mechanism
const feePerInput = 10000
// The minimal change amount to target in order to avoid large storage mass (see KIP9 for more details).
// By having at least 0.2KAS in the change output we make sure that every transaction with send value >= 0.2KAS
// should succeed (at most 50K storage mass for each output, thus overall lower than standard mass upper bound which is 100K gram)
const minChangeTarget = constants.SompiPerKaspa / 5
func (s *server) CreateUnsignedTransactions(_ context.Context, request *pb.CreateUnsignedTransactionsRequest) (
*pb.CreateUnsignedTransactionsResponse, error,
) {
@ -124,9 +129,10 @@ func (s *server) selectUTXOs(spendAmount uint64, isSendAll bool, feePerInput uin
totalSpend := spendAmount + fee
// Two break cases (if not send all):
// 1. totalValue == totalSpend, so there's no change needed -> number of outputs = 1, so a single input is sufficient
// 2. totalValue > totalSpend, so there will be change and 2 outputs, therefor in order to not struggle with new dust
// rules we try and find at least 2 inputs (even though the next one is not necessary in terms of spend value)
if !isSendAll && (totalValue == totalSpend || (totalValue > totalSpend && len(selectedUTXOs) > 1)) {
// 2. totalValue > totalSpend, so there will be change and 2 outputs, therefor in order to not struggle with --
// 2.1 go-nodes dust patch we try and find at least 2 inputs (even though the next one is not necessary in terms of spend value)
// 2.2 KIP9 we try and make sure that the change amount is not too small
if !isSendAll && (totalValue == totalSpend || (totalValue >= totalSpend+minChangeTarget && len(selectedUTXOs) > 1)) {
break
}
}