fix: added merchant_id in models of shipment module

shipment/migrations/0006_add_merchant_to_shipment_and_salesitem.py

@@ -0,0 +1,90 @@
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+def backfill_shipment_salesitem_merchant(apps, schema_editor):
+    """
+    为历史数据补齐 merchant（本项目当前声称未上线，但迁移要可重复执行且安全）。
+    - Shipment.merchant: 从 customer.merchant 推导
+    - SalesItem.merchant:
+        - 优先从 shipment.merchant 推导
+        - 否则从 created_by.employee.merchant 推导（如果存在）
+    """
+    Shipment = apps.get_model('shipment', 'Shipment')
+    SalesItem = apps.get_model('shipment', 'SalesItem')
+
+    # Shipment: merchant = customer.merchant
+    for s in Shipment.objects.filter(merchant__isnull=True).select_related('customer'):
+        if s.customer_id:
+            s.merchant_id = s.customer.merchant_id
+            s.save(update_fields=['merchant'])
+
+    # SalesItem: merchant = shipment.merchant else created_by.employee.merchant
+    # 注意：迁移态下 employee 关系可能不存在，需 try/except
+    for item in SalesItem.objects.filter(merchant__isnull=True).select_related('shipment', 'shipment__merchant', 'created_by'):
+        if item.shipment_id and getattr(item.shipment, 'merchant_id', None):
+            item.merchant_id = item.shipment.merchant_id
+            item.save(update_fields=['merchant'])
+            continue
+
+        user = getattr(item, 'created_by', None)
+        emp = getattr(user, 'employee', None) if user else None
+        merchant_id = getattr(emp, 'merchant_id', None) if emp else None
+        if merchant_id:
+            item.merchant_id = merchant_id
+            item.save(update_fields=['merchant'])
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('basic_info', '0013_alter_customer_options'),
+        ('shipment', '0005_fix_shipment_external_finished_product_relation'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='shipment',
+            name='merchant',
+            field=models.ForeignKey(
+                null=True,
+                on_delete=django.db.models.deletion.PROTECT,
+                related_name='shipments',
+                to='basic_info.merchant',
+                verbose_name='所属商户',
+            ),
+        ),
+        migrations.AddField(
+            model_name='salesitem',
+            name='merchant',
+            field=models.ForeignKey(
+                null=True,
+                on_delete=django.db.models.deletion.PROTECT,
+                related_name='sales_items',
+                to='basic_info.merchant',
+                verbose_name='所属商户',
+            ),
+        ),
+        migrations.RunPython(backfill_shipment_salesitem_merchant, migrations.RunPython.noop),
+        migrations.AlterField(
+            model_name='shipment',
+            name='merchant',
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.PROTECT,
+                related_name='shipments',
+                to='basic_info.merchant',
+                verbose_name='所属商户',
+            ),
+        ),
+        migrations.AlterField(
+            model_name='salesitem',
+            name='merchant',
+            field=models.ForeignKey(
+                on_delete=django.db.models.deletion.PROTECT,
+                related_name='sales_items',
+                to='basic_info.merchant',
+                verbose_name='所属商户',
+            ),
+        ),
+    ]
+