fix: 禁止后台单独取消子订单，避免父订单支付后子订单被复活或余额未退

internal/architecture/order_service_test_structure_test.go

@@ -39,6 +39,7 @@ func TestOrderServiceTestsAreSplitByResponsibility(t *testing.T) {
 			"TestCalcParentStatus", "TestCalcParentStatusAllRefunded", "TestCalcParentStatusPartiallyRefunded",
 			"TestExpectedRefundStatus", "TestResolvedParentStatusPrefersOwnRefund",
 			"TestIsTransitionAllowedRefunded", "TestUpdateOrderStatusParentToPartiallyRefundedSyncsChildren",
+			"TestUpdateOrderStatusRejectsCancelingChildOrder",
 			"TestUpdateOrderStatusRejectsCancelingPaidParent",
 			"TestUpdateOrderStatusRejectsManualPaidTransition",
 			"TestCanCompleteParentOrder", "TestCanCompleteParentOrderRejectInvalidStatus",

internal/modules/order/application/order_service_child.go

@@ -281,6 +281,11 @@ func (s *OrderService) UpdateOrderStatus(orderID uint, targetStatus string) (*or
 	if !IsTransitionAllowed(order.Status, target) {
 		return nil, ErrOrderStatusInvalid
 	}
+	// 子订单不能单独取消：父订单的钱包扣款与优惠券不会随之回滚，
+	// 且父订单后续支付会把已取消的子订单重新置为已支付。取消须针对父订单。
+	if target == constants.OrderStatusCanceled && order.ParentID != nil {
+		return nil, ErrOrderStatusInvalid
+	}
 
 	now := time.Now()
 	updates := map[string]interface{}{

internal/modules/order/application/order_service_status_test.go

@@ -370,3 +370,27 @@ func TestUpdateOrderStatusRejectsCancelingPaidParent(t *testing.T) {
 		t.Fatalf("paid parent status mutated to %s", stored.Status)
 	}
 }
+
+func TestUpdateOrderStatusRejectsCancelingChildOrder(t *testing.T) {
+	dsn := fmt.Sprintf("file:order_service_reject_cancel_child_%d?mode=memory&cache=shared", time.Now().UnixNano())
+	db, err := gorm.Open(sqlite.Open(dsn), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("open sqlite failed: %v", err)
+	}
+	if err := db.AutoMigrate(&orderdomain.Order{}, &orderdomain.OrderItem{}, &fulfillmentdomain.Fulfillment{}); err != nil {
+		t.Fatalf("auto migrate failed: %v", err)
+	}
+	now := time.Now()
+	parent := &orderdomain.Order{OrderNo: "CHILD-CANCEL-PARENT", Status: constants.OrderStatusPendingPayment, Currency: "CNY", CreatedAt: now, UpdatedAt: now}
+	if err := db.Create(parent).Error; err != nil {
+		t.Fatalf("create parent failed: %v", err)
+	}
+	child := &orderdomain.Order{OrderNo: "CHILD-CANCEL-PARENT-A", ParentID: &parent.ID, Status: constants.OrderStatusPendingPayment, Currency: "CNY", CreatedAt: now, UpdatedAt: now}
+	if err := db.Create(child).Error; err != nil {
+		t.Fatalf("create child failed: %v", err)
+	}
+	svc := NewOrderService(OrderServiceOptions{OrderStore: ordergormstore.New(db, "test-guest-credential-secret-with-32-bytes")})
+	if _, err := svc.UpdateOrderStatus(child.ID, constants.OrderStatusCanceled); err != ErrOrderStatusInvalid {
+		t.Fatalf("cancel child error = %v, want %v", err, ErrOrderStatusInvalid)
+	}
+}