fix: Workaround Go Inet marshal bug (#410)

Fix nasty bug triggered by Go bug

golang/go#35727

@shimonp21  can you please confirm this solves the bug triggered by the k8s cidr plugin.

schema/cidr.go

@@ -1,5 +1,7 @@
 package schema
 
+import "encoding/json"
+
 type CIDR Inet
 
 type CIDRTransformer interface {
@@ -36,3 +38,7 @@ func (dst *CIDR) Set(src interface{}) error {
 func (dst CIDR) Get() interface{} {
 	return (Inet)(dst).Get()
 }
+
+func (dst *CIDR) UnmarshalJSON(b []byte) error {
+	return json.Unmarshal(b, (*Inet)(dst))
+}

schema/inet.go

@@ -3,6 +3,7 @@ package schema
 
 import (
 	"encoding"
+	"encoding/json"
 	"fmt"
 	"net"
 	"strings"
@@ -12,6 +13,12 @@ type InetTransformer interface {
 	TransformInet(*Inet) interface{}
 }
 
+// workaround this Golang bug: https://github.com/golang/go/issues/35727
+type inetWrapper struct {
+	IPNet  *net.IPNet
+	Status Status
+}
+
 // Inet represents both inet and cidr PostgreSQL types.
 type Inet struct {
 	IPNet  *net.IPNet
@@ -146,6 +153,22 @@ func maybeGetIPv4(input string, ip net.IP) net.IP {
 	return ip.To4()
 }
 
+// workaround this Golang bug: https://github.com/golang/go/issues/35727
+func (dst *Inet) UnmarshalJSON(b []byte) error {
+	tmp := inetWrapper{}
+	if err := json.Unmarshal(b, &tmp); err != nil {
+		return err
+	}
+	*dst = Inet{Status: tmp.Status}
+	if dst.Status == Present {
+		if err := dst.Set(tmp.IPNet.String()); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func (dst Inet) Get() interface{} {
 	switch dst.Status {
 	case Present:

schema/inet_test.go

@@ -1,6 +1,8 @@
 package schema
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"net"
 	"strings"
@@ -59,3 +61,32 @@ func TestInetSet(t *testing.T) {
 		}
 	}
 }
+
+func TestInetMarshalUnmarshal(t *testing.T) {
+	var r Inet
+	err := r.Set("10.244.0.0/24")
+	if err != nil {
+		t.Fatal(err)
+	}
+	b, err := json.Marshal(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var r2 Inet
+	err = json.Unmarshal(b, &r2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !r.Equal(&r2) {
+		t.Errorf("%v != %v", r, r2)
+	}
+
+	// workaround this Golang bug: https://github.com/golang/go/issues/35727
+	if !bytes.Equal(r.IPNet.Mask, r2.IPNet.Mask) {
+		t.Errorf("%v != %v", r.IPNet.Mask, r2.IPNet.Mask)
+	}
+	//nolint:all
+	if !bytes.Equal(r.IPNet.IP, r2.IPNet.IP) {
+		t.Errorf("%v != %v", r.IPNet.IP, r2.IPNet.IP)
+	}
+}