Use one of the From addresses as a change address

cmd/kaspawallet/config.go

@@ -56,7 +56,7 @@ type sendConfig struct {
 	Password                 string   `long:"password" short:"p" description:"Wallet password"`
 	DaemonAddress            string   `long:"daemonaddress" short:"d" description:"Wallet daemon server to connect to"`
 	ToAddress                string   `long:"to-address" short:"t" description:"The public address to send Kaspa to" required:"true"`
-	FromAddresses            []string `long:"from-address" short:"a" description:"Specific public address to send Kaspa from. Use multiple times to accept several addresses" required:"false"`
+	FromAddresses            []string `long:"from-address" short:"a" description:"Specific public address to send Kaspa from. Use multiple times to accept several addresses (Note: using this flag will send the change to one of the provided addresses)" required:"false"`
 	SendAmount               float64  `long:"send-amount" short:"v" description:"An amount to send in Kaspa (e.g. 1234.12345678)" required:"true"`
 	UseExistingChangeAddress bool     `long:"use-existing-change-address" short:"u" description:"Will use an existing change address (in case no change address was ever used, it will use a new one)"`
 	Verbose                  bool     `long:"show-serialized" short:"s" description:"Show a list of hex encoded sent transactions"`
@@ -72,7 +72,7 @@ type sweepConfig struct {
 type createUnsignedTransactionConfig struct {
 	DaemonAddress            string   `long:"daemonaddress" short:"d" description:"Wallet daemon server to connect to"`
 	ToAddress                string   `long:"to-address" short:"t" description:"The public address to send Kaspa to" required:"true"`
-	FromAddresses            []string `long:"from-address" short:"a" description:"Specific public address to send Kaspa from. Use multiple times to accept several addresses" required:"false"`
+	FromAddresses            []string `long:"from-address" short:"a" description:"Specific public address to send Kaspa from. Use multiple times to accept several addresses (Note: using this flag will send the change to one of the provided addresses)" required:"false"`
 	SendAmount               float64  `long:"send-amount" short:"v" description:"An amount to send in Kaspa (e.g. 1234.12345678)" required:"true"`
 	UseExistingChangeAddress bool     `long:"use-existing-change-address" short:"u" description:"Will use an existing change address (in case no change address was ever used, it will use a new one)"`
 	config.NetworkFlags

cmd/kaspawallet/daemon/server/address.go

@@ -10,27 +10,33 @@ import (
 	"github.com/pkg/errors"
 )
 
-func (s *server) changeAddress(useFirst bool) (util.Address, *walletAddress, error) {
+func (s *server) changeAddress(useFirst bool, fromAddresses []*walletAddress) (util.Address, *walletAddress, error) {
 	internalIndex := uint32(0)
-	if !useFirst {
+	var walletAddr *walletAddress
-		err := s.keysFile.SetLastUsedInternalIndex(s.keysFile.LastUsedInternalIndex() + 1)
+	if len(fromAddresses) != 0 {
-		if err != nil {
+		walletAddr = fromAddresses[0]
-			return nil, nil, err
+	} else {
+		if !useFirst {
+			err := s.keysFile.SetLastUsedInternalIndex(s.keysFile.LastUsedInternalIndex() + 1)
+			if err != nil {
+				return nil, nil, err
+			}
+
+			err = s.keysFile.Save()
+			if err != nil {
+				return nil, nil, err
+			}
+
+			internalIndex = s.keysFile.LastUsedInternalIndex()
 		}
 
-		err = s.keysFile.Save()
+		walletAddr = &walletAddress{
-		if err != nil {
+			index:         internalIndex,
-			return nil, nil, err
+			cosignerIndex: s.keysFile.CosignerIndex,
+			keyChain:      libkaspawallet.InternalKeychain,
 		}
-
-		internalIndex = s.keysFile.LastUsedInternalIndex()
 	}
 
-	walletAddr := &walletAddress{
-		index:         internalIndex,
-		cosignerIndex: s.keysFile.CosignerIndex,
-		keyChain:      libkaspawallet.InternalKeychain,
-	}
 	path := s.walletAddressPath(walletAddr)
 	address, err := libkaspawallet.Address(s.params, s.keysFile.ExtendedPublicKeys, s.keysFile.MinimumSignatures, path, s.keysFile.ECDSA)
 	if err != nil {

cmd/kaspawallet/daemon/server/create_unsigned_transaction.go

@@ -61,7 +61,7 @@ func (s *server) createUnsignedTransactions(address string, amount uint64, fromA
 		return nil, err
 	}
 
-	changeAddress, changeWalletAddress, err := s.changeAddress(useExistingChangeAddress)
+	changeAddress, changeWalletAddress, err := s.changeAddress(useExistingChangeAddress, fromAddresses)
 	if err != nil {
 		return nil, err
 	}