fix: close phase4 overseas acceptance gaps

lastleg-service/src/test/java/com/baiyue/lastleg/procurement/service/OverseasProcurementServiceTest.java

@@ -1,5 +1,7 @@
 package com.baiyue.lastleg.procurement.service;
 
+import com.baomidou.mybatisplus.annotation.FieldStrategy;
+import com.baomidou.mybatisplus.annotation.TableField;
 import com.baiyue.lastleg.procurement.dto.OverseasProcurementRequests;
 import com.baiyue.lastleg.procurement.entity.OverseasProcurementOrder;
 import com.baiyue.lastleg.procurement.mapper.OverseasProcurementOrderMapper;
@@ -21,6 +23,7 @@ import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
@@ -155,4 +158,15 @@ class OverseasProcurementServiceTest {
         order.setUpdatedAt(order.getCreatedAt());
         return order;
     }
+
+    @Test
+    void nullablePatchFieldsArePersistedWhenExplicitlyCleared() throws Exception {
+        for (String field : List.of("productSpecification", "productUrl", "purchaseWarehouseId",
+            "purchaseWarehouseName", "domesticCarrier", "domesticTrackingNo", "overseasCarrier",
+            "overseasTrackingNo", "estimatedArrivalAt", "remark")) {
+            TableField annotation = OverseasProcurementOrder.class.getDeclaredField(field).getAnnotation(TableField.class);
+            assertNotNull(annotation, field);
+            assertEquals(FieldStrategy.ALWAYS, annotation.updateStrategy(), field);
+        }
+    }
 }