优化提现问题

backend/internal/modules/withdrawal/user.go

@@ -8,6 +8,7 @@ import (
 	"hfb_sys/backend/internal/modules/wallet"
 
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 // 用户创建提现申请
@@ -146,22 +147,22 @@ func (r *Repository) FindByID(ctx context.Context, userID, id uint64) (*Withdraw
 
 // 用户取消提现
 func (r *Repository) Cancel(ctx context.Context, userID, id uint64) error {
-	db := r.db.WithContext(ctx)
-	var withdrawal model.WithdrawalRequest
-	if err := db.Where("id = ? AND user_id = ?", id, userID).
-		First(&withdrawal).Error; err != nil {
-		if errors.Is(err, gorm.ErrRecordNotFound) {
-			return ErrWithdrawalNotFound
+	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		var withdrawal model.WithdrawalRequest
+		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
+			Where("id = ? AND user_id = ?", id, userID).
+			First(&withdrawal).Error; err != nil {
+			if errors.Is(err, gorm.ErrRecordNotFound) {
+				return ErrWithdrawalNotFound
+			}
+			return err
 		}
-		return err
-	}
 
-	// 只有待审核状态可以取消
-	if withdrawal.Status != "pending" {
-		return ErrWithdrawalLocked
-	}
+		// 事务内加行锁后重新校验，只有待审核状态可以取消，避免与管理员审核并发重复解冻
+		if withdrawal.Status != "pending" {
+			return ErrWithdrawalLocked
+		}
 
-	return db.Transaction(func(tx *gorm.DB) error {
 		// 更新状态
 		if err := tx.Model(&withdrawal).Update("status", "cancelled").Error; err != nil {
 			return err