pkg/ipnet: Add DeepCopy and DeepCopyInto for IPNet

Devan needs DeepCopyInto on IPNet as part of embed our types into
Hive's ClusterDeployment CRD [1].  You could generate these with
deepcopy-gen [2], but setting up automatic code generation is a bit
heavy for just these methods [3], so we're hand-coding for now.

[1]: openshift#256 (comment)
[2]: https://godoc.org/k8s.io/gengo/examples/deepcopy-gen
[3]: openshift#276 (comment)

pkg/ipnet/ipnet.go

@@ -25,6 +25,26 @@ func (ipnet *IPNet) String() string {
 	return ipnet.IPNet.String()
 }
 
+// DeepCopyInto copies the receiver into out.  out must be non-nil.
+func (ipnet *IPNet) DeepCopyInto(out *IPNet) {
+	if ipnet == nil {
+		*out = *new(IPNet)
+	} else {
+		*out = *ipnet
+	}
+	return
+}
+
+// DeepCopy copies the receiver, creating a new IPNet.
+func (ipnet *IPNet) DeepCopy() *IPNet {
+	if ipnet == nil {
+		return nil
+	}
+	out := new(IPNet)
+	ipnet.DeepCopyInto(out)
+	return out
+}
+
 // MarshalJSON interface for an IPNet
 func (ipnet IPNet) MarshalJSON() (data []byte, err error) {
 	if reflect.DeepEqual(ipnet.IPNet, emptyIPNet) {

pkg/ipnet/ipnet_test.go

@@ -56,3 +56,42 @@ func TestUnmarshal(t *testing.T) {
 		})
 	}
 }
+
+func TestDeepCopy(t *testing.T) {
+	for _, ipNetIn := range []*IPNet{
+		{},
+		{IPNet: net.IPNet{
+			IP:   net.IP{192, 168, 0, 10},
+			Mask: net.IPv4Mask(255, 255, 255, 0),
+		}},
+	} {
+		t.Run(ipNetIn.String(), func(t *testing.T) {
+			t.Run("DeepCopyInto", func(t *testing.T) {
+				ipNetOut := &IPNet{IPNet: net.IPNet{
+					IP:   net.IP{10, 0, 0, 0},
+					Mask: net.IPv4Mask(255, 0, 0, 0),
+				}}
+
+				ipNetIn.DeepCopyInto(ipNetOut)
+				if ipNetOut.String() != ipNetIn.String() {
+					t.Fatalf("%v != %v", ipNetOut, ipNetIn)
+				}
+			})
+
+			t.Run("DeepCopy", func(t *testing.T) {
+				ipNetOut := ipNetIn.DeepCopy()
+				if ipNetOut.String() != ipNetIn.String() {
+					t.Fatalf("%v != %v", ipNetOut, ipNetIn)
+				}
+
+				ipNetIn.IPNet = net.IPNet{
+					IP:   net.IP{192, 168, 10, 10},
+					Mask: net.IPv4Mask(255, 255, 255, 255),
+				}
+				if ipNetOut.String() == ipNetIn.String() {
+					t.Fatalf("%v (%q) == %v (%q)", ipNetOut, ipNetOut.String(), ipNetIn, ipNetIn.String())
+				}
+			})
+		})
+	}
+}