multi: update PaymentAddr to use fn.Option

Since it is allowed to not be set and so can lead to nil deref panics if
it is a pointer.

zpay32/decode.go

@@ -14,6 +14,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil/bech32"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -278,13 +279,19 @@ func parseTaggedFields(invoice *Invoice, fields []byte, net *chaincfg.Params) er
 			invoice.PaymentHash, err = parse32Bytes(base32Data)
 
 		case fieldTypeS:
-			if invoice.PaymentAddr != nil {
+			if invoice.PaymentAddr.IsSome() {
 				// We skip the field if we have already seen a
 				// supported one.
 				continue
 			}
 
-			invoice.PaymentAddr, err = parse32Bytes(base32Data)
+			addr, err := parse32Bytes(base32Data)
+			if err != nil {
+				return err
+			}
+			if addr != nil {
+				invoice.PaymentAddr = fn.Some(*addr)
+			}
 
 		case fieldTypeD:
 			if invoice.Description != nil {

zpay32/encode.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil/bech32"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -301,14 +302,14 @@ func writeTaggedFields(bufferBase32 *bytes.Buffer, invoice *Invoice) error {
 			return err
 		}
 	}
-	if invoice.PaymentAddr != nil {
-		err := writeBytes32(
-			bufferBase32, fieldTypeS, *invoice.PaymentAddr,
-		)
-		if err != nil {
-			return err
-		}
+
+	err := fn.MapOptionZ(invoice.PaymentAddr, func(addr [32]byte) error {
+		return writeBytes32(bufferBase32, fieldTypeS, addr)
+	})
+	if err != nil {
+		return err
 	}
+
 	if invoice.Features.SerializeSize32() > 0 {
 		var b bytes.Buffer
 		err := invoice.Features.RawFeatureVector.EncodeBase32(&b)

zpay32/invoice.go

@@ -8,6 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -136,7 +137,7 @@ type Invoice struct {
 
 	// PaymentAddr is the payment address to be used by payments to prevent
 	// probing of the destination.
-	PaymentAddr *[32]byte
+	PaymentAddr fn.Option[[32]byte]
 
 	// Destination is the public key of the target node. This will always
 	// be set after decoding, and can optionally be set before encoding to
@@ -301,7 +302,7 @@ func Features(features *lnwire.FeatureVector) func(*Invoice) {
 // the desired payment address that is advertised on the invoice.
 func PaymentAddr(addr [32]byte) func(*Invoice) {
 	return func(i *Invoice) {
-		i.PaymentAddr = &addr
+		i.PaymentAddr = fn.Some(addr)
 	}
 }
 

zpay32/invoice_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	sphinx "github.com/lightningnetwork/lightning-onion"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/stretchr/testify/require"
 )
@@ -562,7 +563,7 @@ func TestDecodeEncode(t *testing.T) {
 					MilliSat:    &testMillisat25mBTC,
 					Timestamp:   time.Unix(1496314658, 0),
 					PaymentHash: &testPaymentHash,
-					PaymentAddr: &specPaymentAddr,
+					PaymentAddr: fn.Some(specPaymentAddr),
 					Description: &testCoffeeBeans,
 					Destination: testPubKey,
 					Features: lnwire.NewFeatureVector(
@@ -589,7 +590,7 @@ func TestDecodeEncode(t *testing.T) {
 					MilliSat:    &testMillisat25mBTC,
 					Timestamp:   time.Unix(1496314658, 0),
 					PaymentHash: &testPaymentHash,
-					PaymentAddr: &specPaymentAddr,
+					PaymentAddr: fn.Some(specPaymentAddr),
 					Description: &testCoffeeBeans,
 					Destination: testPubKey,
 					Features: lnwire.NewFeatureVector(
@@ -718,7 +719,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash: &testPaymentHash,
 					Description: &testPaymentMetadata,
 					Destination: testPubKey,
-					PaymentAddr: &specPaymentAddr,
+					PaymentAddr: fn.Some(specPaymentAddr),
 					Features: lnwire.NewFeatureVector(
 						lnwire.NewRawFeatureVector(8, 14, 48),
 						lnwire.Features,
@@ -772,7 +773,7 @@ func TestDecodeEncode(t *testing.T) {
 					MilliSat:    &testMillisat25mBTC,
 					Timestamp:   time.Unix(1496314658, 0),
 					PaymentHash: &testPaymentHash,
-					PaymentAddr: &specPaymentAddr,
+					PaymentAddr: fn.Some(specPaymentAddr),
 					Description: &testCoffeeBeans,
 					Destination: testPubKey,
 					Features: lnwire.NewFeatureVector(
@@ -803,7 +804,7 @@ func TestDecodeEncode(t *testing.T) {
 					MilliSat:    &testMillisat25mBTC,
 					Timestamp:   time.Unix(1496314658, 0),
 					PaymentHash: &testPaymentHash,
-					PaymentAddr: &specPaymentAddr,
+					PaymentAddr: fn.Some(specPaymentAddr),
 					Description: &testCoffeeBeans,
 					Destination: testPubKey,
 					Features: lnwire.NewFeatureVector(