From fdd24fc1d680dbad359776b11ed2af6af22ed4d0 Mon Sep 17 00:00:00 2001
From: Juan Pablo Civile <elementohb@gmail.com>
Date: Fri, 15 Jan 2021 14:56:16 -0300
Subject: [PATCH 1/2] routerrpc: limit max parts if the invoice doesn't declare
 MPP support

---
 lnrpc/routerrpc/router_backend.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lnrpc/routerrpc/router_backend.go b/lnrpc/routerrpc/router_backend.go
index 74775fc5..6bb5b8be 100644
--- a/lnrpc/routerrpc/router_backend.go
+++ b/lnrpc/routerrpc/router_backend.go
@@ -648,6 +648,10 @@ func (r *RouterBackend) extractIntentFromSendRequest(
 			payIntent.Amount = *payReq.MilliSat
 		}
 
+		if !payReq.Features.HasFeature(lnwire.MPPOptional) {
+			payIntent.MaxParts = 1
+		}
+
 		copy(payIntent.PaymentHash[:], payReq.PaymentHash[:])
 		destKey := payReq.Destination.SerializeCompressed()
 		copy(payIntent.Target[:], destKey)

From f574c150aa21ede437f04d62fc748e724c6cf7bf Mon Sep 17 00:00:00 2001
From: Juan Pablo Civile <elementohb@gmail.com>
Date: Fri, 15 Jan 2021 14:56:32 -0300
Subject: [PATCH 2/2] routing: limit max parts if the invoice doesn't declare
 MPP support

---
 routing/payment_session.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/routing/payment_session.go b/routing/payment_session.go
index 2d7ef8bf..4b766d4c 100644
--- a/routing/payment_session.go
+++ b/routing/payment_session.go
@@ -278,6 +278,12 @@ func (p *paymentSession) RequestRoute(maxAmt, feeLimit lnwire.MilliSatoshi,
 				return nil, errNoPathFound
 			}
 
+			if !p.payment.DestFeatures.HasFeature(lnwire.MPPOptional) {
+				p.log.Debug("not splitting because destination doesn't declare MPP")
+
+				return nil, errNoPathFound
+			}
+
 			// No splitting if this is the last shard.
 			isLastShard := activeShards+1 >= p.payment.MaxParts
 			if isLastShard {