If a field in a database table uses the serializer tag and AutoMigrate is used, then even if there are no changes to this field, AutoMigrate will still perform an ALTER on the table every time

db.go

@@ -1,16 +1,12 @@
 package main
 
 import (
+	"gorm.io/driver/mysql"
 	"log"
 	"math/rand"
 	"os"
-	"path/filepath"
 	"time"
 
-	"gorm.io/driver/mysql"
-	"gorm.io/driver/postgres"
-	"gorm.io/driver/sqlite"
-	"gorm.io/driver/sqlserver"
 	"gorm.io/gorm"
 	"gorm.io/gorm/logger"
 	. "gorm.io/playground/models"
@@ -44,34 +40,11 @@ func init() {
 
 func OpenTestConnection() (db *gorm.DB, err error) {
 	dbDSN := os.Getenv("GORM_DSN")
-	switch os.Getenv("GORM_DIALECT") {
-	case "mysql":
-		log.Println("testing mysql...")
-		if dbDSN == "" {
-			dbDSN = "gorm:gorm@tcp(localhost:9910)/gorm?charset=utf8&parseTime=True&loc=Local"
-		}
-		db, err = gorm.Open(mysql.Open(dbDSN), &gorm.Config{})
-	case "postgres":
-		log.Println("testing postgres...")
-		if dbDSN == "" {
-			dbDSN = "user=gorm password=gorm host=localhost dbname=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai"
-		}
-		db, err = gorm.Open(postgres.Open(dbDSN), &gorm.Config{})
-	case "sqlserver":
-		// CREATE LOGIN gorm WITH PASSWORD = 'LoremIpsum86';
-		// CREATE DATABASE gorm;
-		// USE gorm;
-		// CREATE USER gorm FROM LOGIN gorm;
-		// sp_changedbowner 'gorm';
-		log.Println("testing sqlserver...")
-		if dbDSN == "" {
-			dbDSN = "sqlserver://gorm:LoremIpsum86@localhost:9930?database=gorm"
-		}
-		db, err = gorm.Open(sqlserver.Open(dbDSN), &gorm.Config{})
-	default:
-		log.Println("testing sqlite3...")
-		db, err = gorm.Open(sqlite.Open(filepath.Join(os.TempDir(), "gorm.db")), &gorm.Config{})
+	log.Println("testing mysql...")
+	if dbDSN == "" {
+		dbDSN = "gorm:gorm@tcp(localhost:9910)/gorm?charset=utf8&parseTime=True&loc=Local"
 	}
+	db, err = gorm.Open(mysql.Open(dbDSN), &gorm.Config{})
 
 	if debug := os.Getenv("DEBUG"); debug == "true" {
 		db.Logger = db.Logger.LogMode(logger.Info)

go.mod

@@ -29,8 +29,8 @@ require (
 	golang.org/x/crypto v0.41.0 // indirect
 	golang.org/x/exp v0.0.0-20250819193227-8b4c13bb791b // indirect
 	golang.org/x/mod v0.27.0 // indirect
-	golang.org/x/sync v0.16.0 // indirect
-	golang.org/x/text v0.28.0 // indirect
+	golang.org/x/sync v0.17.0 // indirect
+	golang.org/x/text v0.29.0 // indirect
 	golang.org/x/tools v0.36.0 // indirect
 	gorm.io/cmd/gorm v0.1.1-0.20250825094947-30e7d4fa1f1f // indirect
 	gorm.io/datatypes v1.2.5 // indirect

main_test.go

@@ -2,34 +2,30 @@ package main
 
 import (
 	"testing"
-
-	"gorm.io/playground/models"
 )
 
 // GORM_REPO: https://github.com/go-gorm/gorm.git
 // GORM_BRANCH: master
-// TEST_DRIVERS: sqlite, mysql, postgres, sqlserver
+// TEST_DRIVERS: mysql
 
 func TestGORM(t *testing.T) {
-	user := models.User{Name: "jinzhu"}
-
-	DB.Create(&user)
-
-	var result models.User
-	if err := DB.First(&result, user.ID).Error; err != nil {
-		t.Errorf("Failed, got error: %v", err)
+	type GormBugTest struct {
+		IDS []string `gorm:"serializer:json;column:ids;type:varchar(1000);not null;default:'名称';comment:ids" json:"ids"`
 	}
-}
 
-// func TestGORMGen(t *testing.T) {
-// 	user := models.User{Name: "jinzhu2"}
-// 	ctx := context.Background()
-
-// 	gorm.G[models.User](DB).Create(ctx, &user)
+	for i := 0; i < 3; i++ {
+		// If a field in a database table uses the serializer tag and AutoMigrate is used,
+		// then even if there are no changes to this field
+		// ,AutoMigrate will still perform an ALTER on the table every time.
+
+		// This will alter the ids field of the GormBugTest table four times,
+		// even though the field hasn't changed at all.
+		err := DB.AutoMigrate(GormBugTest{})
+		if err != nil {
+			t.Errorf("Failed, got error: %v", err)
+		}
+	}
 
-// 	if u, err := gorm.G[models.User](DB).Where(g.User.ID.Eq(user.ID)).First(ctx); err != nil {
-// 		t.Errorf("Failed, got error: %v", err)
-// 	} else if u.Name != user.Name {
-// 		t.Errorf("Failed, got user name: %v", u.Name)
-// 	}
-// }
+	t.Log("This will alter the ids field of the GormBugTest table four times,even though the field hasn't changed at all.")
+	t.Log("这里会alter四次GormBugTest表的ids字段 虽然字段没有任何变化")
+}