feat: BeforeUpdate hook supports update using struct

callbacks/update.go

@@ -33,6 +33,14 @@ func SetupUpdateReflectValue(db *gorm.DB) {
 func BeforeUpdate(db *gorm.DB) {
 	if db.Error == nil && db.Statement.Schema != nil && !db.Statement.SkipHooks && (db.Statement.Schema.BeforeSave || db.Statement.Schema.BeforeUpdate) {
 		callMethod(db, func(value interface{}, tx *gorm.DB) (called bool) {
+			rv := reflect.ValueOf(value)
+			for rv.Kind() == reflect.Ptr {
+				rv = rv.Elem()
+			}
+			// save a copy before executing the hook so that can find out which fields were modified after the hook is executed.
+			rvClone := reflect.New(rv.Type()).Elem()
+			rvClone.Set(rv)
+
 			if db.Statement.Schema.BeforeSave {
 				if i, ok := value.(BeforeSaveInterface); ok {
 					called = true
@@ -47,6 +55,21 @@ func BeforeUpdate(db *gorm.DB) {
 				}
 			}
 
+			if called {
+				for _, field := range db.Statement.Schema.Fields {
+					if field.PrimaryKey {
+						continue
+					}
+					dbFieldName, ok := field.TagSettings["COLUMN"]
+					if !ok {
+						continue
+					}
+					// compare with the copy value and update the field if there is a difference
+					if !reflect.DeepEqual(rv.FieldByName(field.Name).Interface(), rvClone.FieldByName(field.Name).Interface()) {
+						db.Statement.SetColumn(dbFieldName, rv.FieldByName(field.Name).Interface())
+					}
+				}
+			}
 			return called
 		})
 	}

tests/hooks_test.go

@@ -609,3 +609,39 @@ func TestPropagateUnscoped(t *testing.T) {
 		t.Fatalf("unscoped did not propagate")
 	}
 }
+
+type StructUpdate struct {
+	ID      uint   `gorm:"column:id;primary_key"`
+	Version int    `gorm:"column:version"`
+	Name    string `gorm:"column:name"`
+}
+
+func (StructUpdate) TableName() string {
+	return "struct_updates"
+}
+
+func (su *StructUpdate) BeforeUpdate(*gorm.DB) error {
+	su.Version++
+	return nil
+}
+
+func TestBeforeUpdateWithStructColumn(t *testing.T) {
+	DB.Migrator().DropTable(&StructUpdate{})
+	DB.AutoMigrate(&StructUpdate{})
+
+	su := StructUpdate{
+		ID:      1,
+		Version: 1,
+	}
+	err := DB.Create(&su).Error
+	if err != nil {
+		t.Fatalf("create struct failed: %v", err)
+	}
+
+	sql := DB.ToSQL(func(tx *gorm.DB) *gorm.DB {
+		return tx.Model(&su).Update("name", "demoManito")
+	})
+	if sql != "UPDATE `struct_updates` SET `user_updates`.`name` = `demoManito`, `user_updates`.`version` = 2 WHERE `user_updates`.`id` = 1" {
+		t.Fatalf("invalid sql: %v", sql)
+	}
+}