lnwire/reply_channel_range: assert sorted encodings

lnwire/reply_channel_range.go

@@ -21,6 +21,12 @@ type ReplyChannelRange struct {
 
 	// ShortChanIDs is a slice of decoded short channel ID's.
 	ShortChanIDs []ShortChannelID
+
+	// noSort indicates whether or not to sort the short channel ids before
+	// writing them out.
+	//
+	// NOTE: This should only be used for testing.
+	noSort bool
 }
 
 // NewReplyChannelRange creates a new empty ReplyChannelRange message.
@@ -64,7 +70,7 @@ func (c *ReplyChannelRange) Encode(w io.Writer, pver uint32) error {
 		return err
 	}
 
-	return encodeShortChanIDs(w, c.EncodingType, c.ShortChanIDs, false)
+	return encodeShortChanIDs(w, c.EncodingType, c.ShortChanIDs, c.noSort)
 }
 
 // MsgType returns the integer uniquely identifying this message type on the

lnwire/reply_channel_range_test.go

@@ -0,0 +1,34 @@
+package lnwire
+
+import (
+	"bytes"
+	"testing"
+)
+
+// TestReplyChannelRangeUnsorted tests that decoding a ReplyChannelRange request
+// that contains duplicate or unsorted ids returns an ErrUnsortedSIDs failure.
+func TestReplyChannelRangeUnsorted(t *testing.T) {
+	for _, test := range unsortedSidTests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			req := &ReplyChannelRange{
+				EncodingType: test.encType,
+				ShortChanIDs: test.sids,
+				noSort:       true,
+			}
+
+			var b bytes.Buffer
+			err := req.Encode(&b, 0)
+			if err != nil {
+				t.Fatalf("unable to encode req: %v", err)
+			}
+
+			var req2 ReplyChannelRange
+			err = req2.Decode(bytes.NewReader(b.Bytes()), 0)
+			if _, ok := err.(ErrUnsortedSIDs); !ok {
+				t.Fatalf("expected ErrUnsortedSIDs, got: %T",
+					err)
+			}
+		})
+	}
+}