routing+migration: make payment failure msg optional

Author: bitromortac

channeldb/migration32/mission_control_store.go

@@ -166,7 +166,14 @@ func newPaymentFailure(sourceIdx *int,
 		sourceIdx: tlv.NewPrimitiveRecord[tlv.TlvType0](
 			uint8(*sourceIdx),
 		),
-		msg: tlv.NewRecordT[tlv.TlvType1](failureMessage{failureMsg}),
+	}
+
+	if failureMsg != nil {
+		info.msg = tlv.SomeRecordT(
+			tlv.NewRecordT[tlv.TlvType1](
+				failureMessage{failureMsg},
+			),
+		)
 	}
 
 	return paymentFailure{
@@ -239,8 +246,15 @@ func decodePaymentFailure(r io.Reader, val interface{}, _ *[8]byte,
 
 // paymentFailureInfo holds additional information about a payment failure.
 type paymentFailureInfo struct {
+	// sourceIdx is the hop the error was reported from. To have a
+	// meaningful payment failure, we need to have a source index. Otherwise
+	// we indicate that there was no error information.
 	sourceIdx tlv.RecordT[tlv.TlvType0, uint8]
-	msg       tlv.RecordT[tlv.TlvType1, failureMessage]
+
+	// msg is the error why a payment failed. If we identify the failure of
+	// a certain hop, but aren't able to decode the failure message, we
+	// don't set the failure message, which is why it is an optional record.
+	msg tlv.OptionalRecordT[tlv.TlvType1, failureMessage]
 }
 
 // Record returns a TLV record that can be used to encode/decode a
@@ -266,10 +280,17 @@ func (r *paymentFailureInfo) Record() tlv.Record {
 
 func encodePaymentFailureInfo(w io.Writer, val interface{}, _ *[8]byte) error {
 	if v, ok := val.(*paymentFailureInfo); ok {
+		recordProducers := []tlv.RecordProducer{
+			&v.sourceIdx,
+		}
+		v.msg.WhenSome(
+			func(r tlv.RecordT[tlv.TlvType1, failureMessage]) {
+				recordProducers = append(recordProducers, &r)
+			},
+		)
+
 		return lnwire.EncodeRecordsTo(
-			w, lnwire.ProduceRecordsSorted(
-				&v.sourceIdx, &v.msg,
-			),
+			w, lnwire.ProduceRecordsSorted(recordProducers...),
 		)
 	}
 
@@ -282,14 +303,19 @@ func decodePaymentFailureInfo(r io.Reader, val interface{}, _ *[8]byte,
 	if v, ok := val.(*paymentFailureInfo); ok {
 		var h paymentFailureInfo
 
-		_, err := lnwire.DecodeRecords(
+		msg := tlv.ZeroRecordT[tlv.TlvType1, failureMessage]()
+		typeMap, err := lnwire.DecodeRecords(
 			r,
-			lnwire.ProduceRecordsSorted(&h.sourceIdx, &h.msg)...,
+			lnwire.ProduceRecordsSorted(&h.sourceIdx, &msg)...,
 		)
 		if err != nil {
 			return err
 		}
 
+		if _, ok := typeMap[h.msg.TlvType()]; ok {
+			h.msg = tlv.SomeRecordT(msg)
+		}
+
 		*v = h
 
 		return nil

routing/missioncontrol.go

@@ -849,7 +849,14 @@ func newPaymentFailure(sourceIdx *int,
 		sourceIdx: tlv.NewPrimitiveRecord[tlv.TlvType0](
 			uint8(*sourceIdx),
 		),
-		msg: tlv.NewRecordT[tlv.TlvType1](failureMessage{failureMsg}),
+	}
+
+	if failureMsg != nil {
+		info.msg = tlv.SomeRecordT(
+			tlv.NewRecordT[tlv.TlvType1](
+				failureMessage{failureMsg},
+			),
+		)
 	}
 
 	return paymentFailure{
@@ -922,8 +929,15 @@ func decodePaymentFailure(r io.Reader, val interface{}, _ *[8]byte,
 
 // paymentFailureInfo holds additional information about a payment failure.
 type paymentFailureInfo struct {
+	// sourceIdx is the hop the error was reported from. To have a
+	// meaningful payment failure, we need to have a source index. Otherwise
+	// we indicate that there was no error information.
 	sourceIdx tlv.RecordT[tlv.TlvType0, uint8]
-	msg       tlv.RecordT[tlv.TlvType1, failureMessage]
+
+	// msg is the error why a payment failed. If we identify the failure of
+	// a certain hop, but aren't able to decode the failure message, we
+	// don't set the failure message, which is why it is an optional record.
+	msg tlv.OptionalRecordT[tlv.TlvType1, failureMessage]
 }
 
 // Record returns a TLV record that can be used to encode/decode a
@@ -949,10 +963,17 @@ func (r *paymentFailureInfo) Record() tlv.Record {
 
 func encodePaymentFailureInfo(w io.Writer, val interface{}, _ *[8]byte) error {
 	if v, ok := val.(*paymentFailureInfo); ok {
+		recordProducers := []tlv.RecordProducer{
+			&v.sourceIdx,
+		}
+		v.msg.WhenSome(
+			func(r tlv.RecordT[tlv.TlvType1, failureMessage]) {
+				recordProducers = append(recordProducers, &r)
+			},
+		)
+
 		return lnwire.EncodeRecordsTo(
-			w, lnwire.ProduceRecordsSorted(
-				&v.sourceIdx, &v.msg,
-			),
+			w, lnwire.ProduceRecordsSorted(recordProducers...),
 		)
 	}
 
@@ -965,14 +986,19 @@ func decodePaymentFailureInfo(r io.Reader, val interface{}, _ *[8]byte,
 	if v, ok := val.(*paymentFailureInfo); ok {
 		var h paymentFailureInfo
 
-		_, err := lnwire.DecodeRecords(
+		msg := tlv.ZeroRecordT[tlv.TlvType1, failureMessage]()
+		typeMap, err := lnwire.DecodeRecords(
 			r,
-			lnwire.ProduceRecordsSorted(&h.sourceIdx, &h.msg)...,
+			lnwire.ProduceRecordsSorted(&h.sourceIdx, &msg)...,
 		)
 		if err != nil {
 			return err
 		}
 
+		if _, ok := typeMap[h.msg.TlvType()]; ok {
+			h.msg = tlv.SomeRecordT(msg)
+		}
+
 		*v = h
 
 		return nil

routing/result_interpretation.go

@@ -139,7 +139,14 @@ func (i *interpretedResult) processFail(rt *mcRoute, failure paymentFailure) {
 	failure.info.WhenSome(
 		func(r tlv.RecordT[tlv.TlvType0, paymentFailureInfo]) {
 			idx = int(r.Val.sourceIdx.Val)
-			failMsg = r.Val.msg.Val.FailureMessage
+
+			r.Val.msg.WhenSome(
+				func(msg tlv.RecordT[tlv.TlvType1,
+					failureMessage]) {
+
+					failMsg = msg.Val.FailureMessage
+				},
+			)
 		},
 	)