lnwallet: Change utxo selection for chan opening.

Disallow the usage of unconfirmed funds resulting from the sweeper
subsystem. This avoids side effects because those utxos can still
be RBFed by the sweeper.

lnwallet/wallet.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"math"
 	"net"
+	"strings"
 	"sync"
 	"sync/atomic"
 
@@ -25,6 +26,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
+	"github.com/lightningnetwork/lnd/labels"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 	"github.com/lightningnetwork/lnd/lnwallet/chanfunding"
 	"github.com/lightningnetwork/lnd/lnwallet/chanvalidate"
@@ -2544,6 +2546,28 @@ func (c *CoinSource) ListCoins(minConfs int32,
 
 	var coins []wallet.Coin
 	for _, utxo := range utxos {
+		// We don't include utxos which are unconfirmed yet and
+		// resulted from the sweeper subsystem, because those
+		// unconfirmed utxos can still be RBFed therefore causing side
+		// effects especially when opening zeroconf channels.
+		if utxo.Confirmations == 0 {
+			label, err := c.wallet.FetchTxLabel(utxo.Hash)
+			if err != nil {
+				return nil, err
+			}
+
+			sweepLabel := labels.MakeLabel(
+				labels.LabelTypeSweepTransaction, nil)
+
+			if strings.Contains(label, sweepLabel) {
+				walletLog.Infof("Cannot use unconfirmed "+
+					"utxo=%v because it used by the "+
+					"sweeper", utxo.OutPoint)
+
+				continue
+			}
+		}
+
 		coins = append(coins, wallet.Coin{
 			TxOut: wire.TxOut{
 				Value:    int64(utxo.Value),