Fix behaviour on deleting parent stock item

InvenTree/stock/migrations/0073_alter_stockitem_parent.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.2.10 on 2021-12-20 13:54
+
+from django.db import migrations
+import django.db.models.deletion
+import mptt.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0072_remove_stockitem_scheduled_for_deletion'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='stockitem',
+            name='parent',
+            field=mptt.fields.TreeForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='children', to='stock.stockitem', verbose_name='Parent Stock Item'),
+        ),
+    ]

InvenTree/stock/models.py

@@ -458,7 +458,7 @@ class StockItem(MPTTModel):
     parent = TreeForeignKey(
         'self',
         verbose_name=_('Parent Stock Item'),
-        on_delete=models.DO_NOTHING,
+        on_delete=models.SET_NULL,
         blank=True, null=True,
         related_name='children'
     )
@@ -1252,6 +1252,7 @@ class StockItem(MPTTModel):
         self.add_tracking_entry(
             StockHistoryCode.MERGED_STOCK_ITEMS,
             user,
+            quantity=self.quantity,
             notes=notes,
             deltas={
                 'location': location.pk,

InvenTree/templates/js/translated/stock.js

@@ -867,7 +867,7 @@ function mergeStockItems(items, options={}) {
                         }
                     }
                 }
-            )
+            );
         }
     });
 }