From feacf577b397f0f1a786d1d6933f32d1ea624697 Mon Sep 17 00:00:00 2001
From: demoManito <1430482733@qq.com>
Date: Wed, 21 Aug 2024 21:45:57 +0800
Subject: [PATCH] feat: BeforeUpdate hook supports update using struct

---
 callbacks/update.go | 48 +++++++++++++++++++++++++++++++++++----------
 tests/hooks_test.go | 41 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 10 deletions(-)

diff --git a/callbacks/update.go b/callbacks/update.go
index 7cde7f61..7e0ebd9a 100644
--- a/callbacks/update.go
+++ b/callbacks/update.go
@@ -32,22 +32,50 @@ func SetupUpdateReflectValue(db *gorm.DB) {
 // BeforeUpdate before update hooks
 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) {
+		callMethod(db, func(value interface{}, tx *gorm.DB) bool {
+			var (
+				beforeSaveInterface   BeforeSaveInterface
+				isBeforeSaveHook      bool
+				beforeUpdateInterface BeforeUpdateInterface
+				isBeforeUpdateHook    bool
+			)
 			if db.Statement.Schema.BeforeSave {
-				if i, ok := value.(BeforeSaveInterface); ok {
-					called = true
-					db.AddError(i.BeforeSave(tx))
-				}
+				beforeSaveInterface, isBeforeSaveHook = value.(BeforeSaveInterface)
 			}
-
 			if db.Statement.Schema.BeforeUpdate {
-				if i, ok := value.(BeforeUpdateInterface); ok {
-					called = true
-					db.AddError(i.BeforeUpdate(tx))
+				beforeUpdateInterface, isBeforeUpdateHook = value.(BeforeUpdateInterface)
+			}
+			if !isBeforeSaveHook && !isBeforeUpdateHook {
+				return false
+			}
+
+			// save a snapshot of the struct before the hook was called
+			rv := reflect.Indirect(reflect.ValueOf(value))
+			rvSnapshot := reflect.New(rv.Type()).Elem()
+			rvSnapshot.Set(rv)
+
+			if isBeforeSaveHook {
+				db.AddError(beforeSaveInterface.BeforeSave(tx))
+			}
+			if isBeforeUpdateHook {
+				db.AddError(beforeUpdateInterface.BeforeUpdate(tx))
+			}
+
+			for _, field := range db.Statement.Schema.Fields {
+				if field.PrimaryKey {
+					continue
+				}
+				dbFieldName, ok := field.TagSettings["COLUMN"]
+				if !ok {
+					continue
+				}
+				// compare with the snapshot and update the field if there is a difference
+				if !reflect.DeepEqual(rv.FieldByName(field.Name).Interface(), rvSnapshot.FieldByName(field.Name).Interface()) {
+					db.Statement.SetColumn(dbFieldName, rv.FieldByName(field.Name).Interface())
 				}
 			}
 
-			return called
+			return true
 		})
 	}
 }
diff --git a/tests/hooks_test.go b/tests/hooks_test.go
index 04f62bde..a3cbbc72 100644
--- a/tests/hooks_test.go
+++ b/tests/hooks_test.go
@@ -609,3 +609,44 @@ 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)
+	}
+
+	err = DB.Model(&su).Update("name", "demoManito").Error
+	if err != nil {
+		t.Fatalf("update struct failed: %v", err)
+	}
+	if su.Version != 2 {
+		t.Fatalf("update version failed: %v", su.Version)
+	}
+	err = DB.Find(&su, "id = ?", 1).Error
+	if err != nil {
+		t.Fatalf("find struct failed: %v", err)
+	}
+}