From cfa9e954c7c0026262553d15381a6180214ee383 Mon Sep 17 00:00:00 2001
From: Conner Fromknecht <conner@lightning.engineering>
Date: Wed, 24 Mar 2021 19:52:38 -0700
Subject: [PATCH] channeldb/invoice: allow creating AMP invoices w/o preiamge

---
 channeldb/invoices.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/channeldb/invoices.go b/channeldb/invoices.go
index 2dcd1be8..fbec1a39 100644
--- a/channeldb/invoices.go
+++ b/channeldb/invoices.go
@@ -719,7 +719,12 @@ func validateInvoice(i *Invoice, paymentHash lntypes.Hash) error {
 		return err
 	}
 
-	if i.Terms.PaymentPreimage == nil && !i.HodlInvoice {
+	// AMP invoices and hodl invoices are allowed to have no preimage
+	// specified.
+	isAMP := i.Terms.Features.HasFeature(
+		lnwire.AMPOptional,
+	)
+	if i.Terms.PaymentPreimage == nil && !(i.HodlInvoice || isAMP) {
 		return errors.New("non-hodl invoices must have a preimage")
 	}