From f27e0baf7c579dc1a68ba5d22663586ff4a99971 Mon Sep 17 00:00:00 2001
From: Wilmer Paulino <wilmer.paulino@gmail.com>
Date: Mon, 11 Jun 2018 16:25:34 -0700
Subject: [PATCH] rpcserver: return err when paying 0 amt invoice and amt is
 not specified

---
 rpcserver.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/rpcserver.go b/rpcserver.go
index 8383b6e0..d976ed49 100644
--- a/rpcserver.go
+++ b/rpcserver.go
@@ -1890,6 +1890,12 @@ func extractPaymentIntent(rpcPayReq *rpcPaymentRequest) (rpcPaymentIntent, error
 		// We override the amount to pay with the amount provided from
 		// the payment request.
 		if payReq.MilliSat == nil {
+			if rpcPayReq.Amt == 0 {
+				return payIntent, errors.New("amount must be " +
+					"specified when paying a zero amount " +
+					"invoice")
+			}
+
 			payIntent.msat = lnwire.NewMSatFromSatoshis(
 				btcutil.Amount(rpcPayReq.Amt),
 			)