From 9edbf2c1034064f11a0cd17f60da5412a9a7963c Mon Sep 17 00:00:00 2001
From: arkadiuszos4chain <arkadiusz.osowski@4chain.studio>
Date: Tue, 3 Oct 2023 18:26:53 +0200
Subject: [PATCH] fix(BUX-255): kahn sorting: ignore inputs we do not use for
 the transaction

---
 beef_tx.go              |  4 ++--
 beef_tx_sorting.go      | 11 +++++++----
 beef_tx_sorting_test.go |  4 ++--
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/beef_tx.go b/beef_tx.go
index 34b4c93f..0d01670a 100644
--- a/beef_tx.go
+++ b/beef_tx.go
@@ -28,8 +28,8 @@ type beefTx struct {
 }
 
 func newBeefTx(version uint32, tx *Transaction) (*beefTx, error) {
-	if version > 65_535 {
-		return nil, errors.New("version above 65.535")
+	if version > 0xFFFF {
+		return nil, errors.New("version above 0xFFFF")
 	}
 
 	// get inputs parent transactions
diff --git a/beef_tx_sorting.go b/beef_tx_sorting.go
index de2dc836..129b063e 100644
--- a/beef_tx_sorting.go
+++ b/beef_tx_sorting.go
@@ -28,16 +28,19 @@ func prepareSortStructures(dag []*Transaction) (txByID map[string]*Transaction,
 		incomingEdgesMap[tx.ID] = 0
 	}
 
-	calculateIncomingEdges(incomingEdgesMap, dag)
+	calculateIncomingEdges(incomingEdgesMap, txByID)
 	zeroIncomingEdgeQueue = getTxWithZeroIncomingEdges(incomingEdgesMap)
 
 	return
 }
 
-func calculateIncomingEdges(inDegree map[string]int, transactions []*Transaction) {
-	for _, tx := range transactions {
+func calculateIncomingEdges(inDegree map[string]int, txByID map[string]*Transaction) {
+	for _, tx := range txByID {
 		for _, input := range tx.draftTransaction.Configuration.Inputs {
-			inDegree[input.UtxoPointer.TransactionID]++
+			inputUtxoTxID := input.UtxoPointer.TransactionID
+			if _, ok := txByID[inputUtxoTxID]; ok { // transaction can contains inputs we are not interested in
+				inDegree[inputUtxoTxID]++
+			}
 		}
 	}
 }
diff --git a/beef_tx_sorting_test.go b/beef_tx_sorting_test.go
index dec96e01..0fb5f1cd 100644
--- a/beef_tx_sorting_test.go
+++ b/beef_tx_sorting_test.go
@@ -12,10 +12,10 @@ func Test_kahnTopologicalSortTransaction(t *testing.T) {
 	txsFromOldestToNewest := []*Transaction{
 		createTx("0"),
 		createTx("1", "0"),
-		createTx("2", "1"),
+		createTx("2", "1", "101"),
 		createTx("3", "2", "1"),
 		createTx("4", "3", "1"),
-		createTx("5", "3", "2"),
+		createTx("5", "3", "2", "100"),
 		createTx("6", "4", "2", "0"),
 		createTx("7", "6", "5", "3", "1"),
 		createTx("8", "7"),