fix history when merging

src/backend/InvenTree/stock/models.py

@@ -2185,7 +2185,8 @@ class StockItem(
             return None
 
         candidates = list(
-            StockItem.objects.filter(part=self.part, location=location)
+            StockItem.objects
+            .filter(part=self.part, location=location)
             .exclude(pk=self.pk)
             .order_by('pk')
         )
@@ -2214,8 +2215,11 @@ class StockItem(
         *This* stock item subsumes the other, which is essentially deleted:
 
         - The quantity of this StockItem is increased
-        - Tracking history for the *other* item is copied to this item
+        - Tracking history for the *other* item is copied to this item (unless copy_history=False)
         - Any allocations (build order, sales order) are moved to this StockItem
+
+        kwargs:
+            copy_history: If True (default), copy tracking from merged items. Set False for merge-on-transfer.
         """
         if isinstance(other_items, StockItem):
             other_items = [other_items]
@@ -2229,6 +2233,7 @@ class StockItem(
         user = kwargs.get('user')
         location = kwargs.get('location', self.location)
         notes = kwargs.get('notes') or ''
+        copy_history = kwargs.pop('copy_history', True)
 
         parent_id = self.parent.pk if self.parent else None
 
@@ -2270,17 +2275,15 @@ class StockItem(
                 self.parent = None
                 self.save()
 
-            self.copyHistoryFrom(other)
+            if copy_history:
+                self.copyHistoryFrom(other)
 
             if other.location:
                 location_note = _('Transferred from %(location)s') % {
                     'location': other.location.pathstring
                 }
 
-                if notes:
+                notes = f'{notes}\n{location_note}' if notes else location_note
-                    notes = f'{notes}\n{location_note}'
-                else:
-                    notes = location_note
 
             other.delete()
 

src/backend/InvenTree/stock/serializers.py

@@ -1883,6 +1883,7 @@ class StockTransferSerializer(StockAdjustmentSerializer):
                             'location': location,
                             'notes': notes,
                             'user': request.user,
+                            'copy_history': False,
                             **kwargs,
                         }
 
@@ -1897,9 +1898,7 @@ class StockTransferSerializer(StockAdjustmentSerializer):
                             )
                             target.merge_stock_items([piece], **merge_kwargs)
                         else:
-                            target.merge_stock_items(
+                            target.merge_stock_items([stock_item], **merge_kwargs)
-                                [stock_item], **merge_kwargs
-                            )
 
                         continue
 

src/backend/InvenTree/stock/test_api.py

@@ -2166,6 +2166,9 @@ class StockTransferMergeTest(StockAPITestCase):
         self.source_loc = StockLocation.objects.get(pk=5)
         self.url = reverse('api-stock-transfer')
 
+        # Remove fixture stock at the destination so merge targets are deterministic
+        StockItem.objects.filter(part=self.part, location=self.dest).delete()
+
     def test_transfer_without_merge_creates_separate_lot(self):
         """Transfer without merge leaves multiple stock rows at destination."""
         existing = StockItem.objects.create(
@@ -2219,8 +2222,8 @@ class StockTransferMergeTest(StockAPITestCase):
         self.assertEqual(existing.quantity, 150)
         self.assertFalse(StockItem.objects.filter(pk=incoming.pk).exists())
 
-    def test_transfer_merge_preserves_tracking(self):
+    def test_transfer_merge_does_not_copy_source_tracking(self):
-        """Transfer merge copies tracking history onto the surviving stock item."""
+        """Transfer merge keeps destination history and adds a single merge entry."""
         existing = StockItem.objects.create(
             part=self.part, location=self.dest, quantity=100
         )
@@ -2229,9 +2232,7 @@ class StockTransferMergeTest(StockAPITestCase):
         )
 
         incoming.add_tracking_entry(
-            StockHistoryCode.STOCK_UPDATE,
+            StockHistoryCode.STOCK_UPDATE, self.user, notes='Source tracking entry'
-            self.user,
-            notes='Source tracking entry',
         )
 
         tracking_count = existing.tracking_info.count()
@@ -2248,10 +2249,15 @@ class StockTransferMergeTest(StockAPITestCase):
 
         existing.refresh_from_db()
 
-        self.assertTrue(
+        self.assertFalse(
             existing.tracking_info.filter(notes='Source tracking entry').exists()
         )
-        self.assertGreater(existing.tracking_info.count(), tracking_count)
+        self.assertEqual(existing.tracking_info.count(), tracking_count + 1)
+        self.assertTrue(
+            existing.tracking_info.filter(
+                tracking_type=StockHistoryCode.MERGED_STOCK_ITEMS
+            ).exists()
+        )
 
 
 class StockItemDeletionTest(StockAPITestCase):