From 06905db6df47fd825423e9f912d42af0cdc1e4cd Mon Sep 17 00:00:00 2001
From: Callan Bryant <callan.bryant@gmail.com>
Date: Mon, 26 Oct 2020 22:47:02 +0000
Subject: [PATCH] allow empty IPNets

---
 exttypes.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/exttypes.go b/exttypes.go
index 86165f8..3d13d1b 100644
--- a/exttypes.go
+++ b/exttypes.go
@@ -17,6 +17,14 @@ func (n JSONIPNet) MarshalJSON() ([]byte, error) {
 
 func (n *JSONIPNet) UnmarshalJSON(b []byte) error {
 	cidr := strings.Trim(string(b), "\"")
+
+	if cidr == "" {
+		// Leave as empty/uninitialised IPNet. A bit like omitempty behaviour,
+		// but we can leave the field there and blank which is useful if the
+		// user wishes to add the cidr manually.
+		return nil
+	}
+
 	IP, IPNet, err := net.ParseCIDR(cidr)
 
 	if err == nil {