zpay32: ensure feature vector is always populated

zpay32/invoice.go

@@ -257,7 +257,8 @@ func RouteHint(routeHint []HopHint) func(*Invoice) {
 }
 
 // Features is a functional option that allows callers of NewInvoice to set the
-// desired feature bits that are advertised on the invoice.
+// desired feature bits that are advertised on the invoice. If this option is
+// not used, an empty feature vector will automatically be populated.
 func Features(features *lnwire.FeatureVector) func(*Invoice) {
 	return func(i *Invoice) {
 		i.Features = features
@@ -290,6 +291,13 @@ func NewInvoice(net *chaincfg.Params, paymentHash [32]byte,
 		option(invoice)
 	}
 
+	// If no features were set, we'll populate an empty feature vector.
+	if invoice.Features == nil {
+		invoice.Features = lnwire.NewFeatureVector(
+			nil, lnwire.Features,
+		)
+	}
+
 	if err := validateInvoice(invoice); err != nil {
 		return nil, err
 	}
@@ -398,6 +406,13 @@ func Decode(invoice string, net *chaincfg.Params) (*Invoice, error) {
 		decodedInvoice.Destination = pubkey
 	}
 
+	// If no feature vector was decoded, populate an empty one.
+	if decodedInvoice.Features == nil {
+		decodedInvoice.Features = lnwire.NewFeatureVector(
+			nil, lnwire.Features,
+		)
+	}
+
 	// Now that we have created the invoice, make sure it has the required
 	// fields set.
 	if err := validateInvoice(&decodedInvoice); err != nil {
@@ -586,6 +601,11 @@ func validateInvoice(invoice *Invoice) error {
 			len(invoice.Destination.SerializeCompressed()))
 	}
 
+	// Ensure that all invoices have feature vectors.
+	if invoice.Features == nil {
+		return fmt.Errorf("missing feature vector")
+	}
+
 	return nil
 }
 
@@ -1070,7 +1090,7 @@ func writeTaggedFields(bufferBase32 *bytes.Buffer, invoice *Invoice) error {
 			return err
 		}
 	}
-	if invoice.Features != nil && invoice.Features.SerializeSize32() > 0 {
+	if invoice.Features.SerializeSize32() > 0 {
 		var b bytes.Buffer
 		err := invoice.Features.RawFeatureVector.EncodeBase32(&b)
 		if err != nil {

zpay32/invoice_test.go

@@ -105,6 +105,8 @@ var (
 		},
 	}
 
+	emptyFeatures = lnwire.NewFeatureVector(nil, lnwire.Features)
+
 	// Must be initialized in init().
 	testDescriptionHash [32]byte
 
@@ -190,6 +192,7 @@ func TestDecodeEncode(t *testing.T) {
 					Timestamp:       time.Unix(1496314658, 0),
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
+					Features:        emptyFeatures,
 				}
 			},
 		},
@@ -206,6 +209,7 @@ func TestDecodeEncode(t *testing.T) {
 					Description:     &testPleaseConsider,
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
+					Features:        emptyFeatures,
 				}
 			},
 		},
@@ -220,6 +224,7 @@ func TestDecodeEncode(t *testing.T) {
 					Timestamp:   time.Unix(1496314658, 0),
 					PaymentHash: &testPaymentHash,
 					Destination: testPubKey,
+					Features:    emptyFeatures,
 				}
 			},
 		},
@@ -235,6 +240,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash: &testPaymentHash,
 					Description: &testPleaseConsider,
 					Destination: testPubKey,
+					Features:    emptyFeatures,
 				}
 			},
 			skipEncoding: true, // Skip encoding since we don't have the unknown fields to encode.
@@ -251,6 +257,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash:     &testPaymentHash,
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
+					Features:        emptyFeatures,
 				}
 			},
 			skipEncoding: true, // Skip encoding since we don't have the unknown fields to encode.
@@ -267,6 +274,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash:     &testPaymentHash,
 					Destination:     testPubKey,
 					DescriptionHash: &testDescriptionHash,
+					Features:        emptyFeatures,
 				}
 			},
 			skipEncoding: true, // Skip encoding since we don't have the unknown fields to encode.
@@ -282,6 +290,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash: &testPaymentHash,
 					Description: &testCupOfCoffee,
 					Destination: testPubKey,
+					Features:    emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -302,6 +311,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash: &testPaymentHash,
 					Description: &testPleaseConsider,
 					Destination: testPubKey,
+					Features:    emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -323,6 +333,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash: &testPaymentHash,
 					Destination: testPubKey,
 					Description: &testEmptyString,
+					Features:    emptyFeatures,
 				}
 			},
 		},
@@ -382,6 +393,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash:     &testPaymentHash,
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -404,6 +416,7 @@ func TestDecodeEncode(t *testing.T) {
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
 					FallbackAddr:    testAddrTestnet,
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -427,6 +440,7 @@ func TestDecodeEncode(t *testing.T) {
 					Destination:     testPubKey,
 					FallbackAddr:    testRustyAddr,
 					RouteHints:      [][]HopHint{testSingleHop},
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -450,6 +464,7 @@ func TestDecodeEncode(t *testing.T) {
 					Destination:     testPubKey,
 					FallbackAddr:    testRustyAddr,
 					RouteHints:      [][]HopHint{testDoubleHop},
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -472,6 +487,7 @@ func TestDecodeEncode(t *testing.T) {
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
 					FallbackAddr:    testAddrMainnetP2SH,
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -547,6 +563,7 @@ func TestDecodeEncode(t *testing.T) {
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
 					FallbackAddr:    testAddrMainnetP2WPKH,
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -569,6 +586,7 @@ func TestDecodeEncode(t *testing.T) {
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
 					FallbackAddr:    testAddrMainnetP2WSH,
+					Features:        emptyFeatures,
 				}
 			},
 			beforeEncoding: func(i *Invoice) {
@@ -628,6 +646,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash: &testPaymentHash,
 					Destination: testPubKey,
 					Description: &testEmptyString,
+					Features:    emptyFeatures,
 				}
 			},
 			skipEncoding: true, // Skip encoding since we were given the wrong net
@@ -645,6 +664,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash:     &testPaymentHash,
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
+					Features:        emptyFeatures,
 				}
 			},
 		},
@@ -660,6 +680,7 @@ func TestDecodeEncode(t *testing.T) {
 					PaymentHash:     &testPaymentHash,
 					DescriptionHash: &testDescriptionHash,
 					Destination:     testPubKey,
+					Features:        emptyFeatures,
 				}
 			},
 		},
@@ -983,7 +1004,7 @@ func compareInvoices(expected, actual *Invoice) error {
 
 	if !reflect.DeepEqual(expected.Features, actual.Features) {
 		return fmt.Errorf("expected features %v, got %v",
-			expected.Features.RawFeatureVector, actual.Features.RawFeatureVector)
+			expected.Features, actual.Features)
 	}
 
 	return nil