fix

internal/application/product/subscription_application_service_impl.go

@@ -214,13 +214,18 @@ func (s *SubscriptionApplicationServiceImpl) convertToSubscriptionInfoResponse(s
 		}
 	}
 
+	var productResponse *responses.ProductSimpleResponse
+	if subscription.Product != nil {
+		productResponse = s.convertToProductSimpleResponse(subscription.Product)
+	}
+
 	return &responses.SubscriptionInfoResponse{
 		ID:        subscription.ID,
 		UserID:    subscription.UserID,
 		ProductID: subscription.ProductID,
 		Price:     subscription.Price.InexactFloat64(),
 		User:      userInfo,
-		Product:   s.convertToProductSimpleResponse(subscription.Product),
+		Product:   productResponse,
 		APIUsed:   subscription.APIUsed,
 		CreatedAt: subscription.CreatedAt,
 		UpdatedAt: subscription.UpdatedAt,
@@ -229,6 +234,11 @@ func (s *SubscriptionApplicationServiceImpl) convertToSubscriptionInfoResponse(s
 
 // convertToProductSimpleResponse 转换为产品简单信息响应
 func (s *SubscriptionApplicationServiceImpl) convertToProductSimpleResponse(product *entities.Product) *responses.ProductSimpleResponse {
+	var categoryResponse *responses.CategorySimpleResponse
+	if product.Category != nil {
+		categoryResponse = s.convertToCategorySimpleResponse(product.Category)
+	}
+
 	return &responses.ProductSimpleResponse{
 		ID:          product.ID,
 		OldID:       product.OldID,
@@ -236,13 +246,17 @@ func (s *SubscriptionApplicationServiceImpl) convertToProductSimpleResponse(prod
 		Code:        product.Code,
 		Description: product.Description,
 		Price:       product.Price.InexactFloat64(),
-		Category:    s.convertToCategorySimpleResponse(product.Category),
+		Category:    categoryResponse,
 		IsPackage:   product.IsPackage,
 	}
 }
 
 // convertToCategorySimpleResponse 转换为分类简单信息响应
 func (s *SubscriptionApplicationServiceImpl) convertToCategorySimpleResponse(category *entities.ProductCategory) *responses.CategorySimpleResponse {
+	if category == nil {
+		return nil
+	}
+	
 	return &responses.CategorySimpleResponse{
 		ID:   category.ID,
 		Name: category.Name,