From ab5f80a8d81c1955e92224b24dfc9bc8c7d387a0 Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Tue, 18 Oct 2022 15:44:47 +0800
Subject: [PATCH] Save as NULL for nil object serialized into json

---
 schema/serializer.go     | 3 +++
 tests/go.mod             | 4 ++--
 tests/serializer_test.go | 3 ++-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/schema/serializer.go b/schema/serializer.go
index 00a4f85f..fef39d9b 100644
--- a/schema/serializer.go
+++ b/schema/serializer.go
@@ -100,6 +100,9 @@ func (JSONSerializer) Scan(ctx context.Context, field *Field, dst reflect.Value,
 // Value implements serializer interface
 func (JSONSerializer) Value(ctx context.Context, field *Field, dst reflect.Value, fieldValue interface{}) (interface{}, error) {
 	result, err := json.Marshal(fieldValue)
+	if string(result) == "null" {
+		return nil, err
+	}
 	return string(result), err
 }
 
diff --git a/tests/go.mod b/tests/go.mod
index 2fef9d97..9c87ca34 100644
--- a/tests/go.mod
+++ b/tests/go.mod
@@ -7,10 +7,10 @@ require (
 	github.com/jinzhu/now v1.1.5
 	github.com/lib/pq v1.10.7
 	golang.org/x/crypto v0.0.0-20221012134737-56aed061732a // indirect
-	golang.org/x/text v0.3.8 // indirect
+	golang.org/x/text v0.4.0 // indirect
 	gorm.io/driver/mysql v1.4.3
 	gorm.io/driver/postgres v1.4.4
-	gorm.io/driver/sqlite v1.4.2
+	gorm.io/driver/sqlite v1.4.3
 	gorm.io/driver/sqlserver v1.4.1
 	gorm.io/gorm v1.24.0
 )
diff --git a/tests/serializer_test.go b/tests/serializer_test.go
index 946536bf..17bfefe2 100644
--- a/tests/serializer_test.go
+++ b/tests/serializer_test.go
@@ -18,6 +18,7 @@ type SerializerStruct struct {
 	gorm.Model
 	Name                   []byte                 `gorm:"json"`
 	Roles                  Roles                  `gorm:"serializer:json"`
+	Roles2                 *Roles                 `gorm:"serializer:json"`
 	Contracts              map[string]interface{} `gorm:"serializer:json"`
 	JobInfo                Job                    `gorm:"type:bytes;serializer:gob"`
 	CreatedTime            int64                  `gorm:"serializer:unixtime;type:time"` // store time in db, use int as field type
@@ -108,7 +109,7 @@ func TestSerializer(t *testing.T) {
 	}
 
 	var result SerializerStruct
-	if err := DB.First(&result, data.ID).Error; err != nil {
+	if err := DB.Where("roles2 IS NULL").First(&result, data.ID).Error; err != nil {
 		t.Fatalf("failed to query data, got error %v", err)
 	}