Add configurable default for PO line item merging (#12472)

* Add configurable default for PO line item merging

Introduce PURCHASEORDER_MERGE_LINE_ITEMS global setting to control the
default state of the merge_items option when creating purchase order lines.

Fixes #10947

* Apply ruff and biome formatting for CI

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Adds configurable default for merging purchase order line items via the `PURCHASEORDER_MERGE_LINE_ITEMS` global setting
 - [#12393](https://github.com/inventree/InvenTree/pull/12393) adds "discount" attribute to order line items, allowing users to specify a discount for each line item on an order. The discount can be specified as either a percentage or a fixed amount, and is applied to the line item total when calculating the order total.
 - [#12391](https://github.com/inventree/InvenTree/pull/12391) adds facility for bulk deleting line items against orders
 - [#12388](https://github.com/inventree/InvenTree/pull/12388) adds uniqueness requirements options for the Parameter and ParameterTemplate models. This allows users to specify whether a parameter value should be unique for a given model type, or globally unique across all models.

docs/docs/purchasing/purchase_order.md

@@ -225,3 +225,4 @@ The following [global settings](../settings/global.md) are available for purchas
 {{ globalsetting("PURCHASEORDER_CONVERT_CURRENCY") }}
 {{ globalsetting("PURCHASEORDER_EDIT_COMPLETED_ORDERS") }}
 {{ globalsetting("PURCHASEORDER_AUTO_COMPLETE") }}
+{{ globalsetting("PURCHASEORDER_MERGE_LINE_ITEMS") }}

src/backend/InvenTree/common/setting/system.py

@@ -1003,6 +1003,14 @@ SYSTEM_SETTINGS: dict[str, InvenTreeSettingsKeyType] = {
         'default': True,
         'validator': bool,
     },
+    'PURCHASEORDER_MERGE_LINE_ITEMS': {
+        'name': _('Merge Purchase Order Line Items'),
+        'description': _(
+            'Merge new purchase order line items with existing lines that share the same part, destination, and target date'
+        ),
+        'default': True,
+        'validator': bool,
+    },
     # login / SSO
     'LOGIN_ENABLE_PWD_FORGOT': {
         'name': _('Enable password forgot'),

src/backend/InvenTree/order/api.py

@@ -684,7 +684,14 @@ class PurchaseOrderLineItemList(
 
         # possibly merge duplicate items
         line_item = None
-        if data.get('merge_items', True):
+        merge_items = data.get(
+            'merge_items',
+            common.settings.get_global_setting(
+                'PURCHASEORDER_MERGE_LINE_ITEMS', backup_value=True
+            ),
+        )
+
+        if merge_items:
             with transaction.atomic():
                 # Lock the matching row, so concurrent line creations cannot
                 # both read the same starting quantity (lost update)

src/backend/InvenTree/order/serializers.py

@@ -745,6 +745,14 @@ class PurchaseOrderLineItemSerializer(
         write_only=True,
     )
 
+    def __init__(self, *args, **kwargs):
+        """Set dynamic defaults for create-only fields."""
+        super().__init__(*args, **kwargs)
+
+        self.fields['merge_items'].default = get_global_setting(
+            'PURCHASEORDER_MERGE_LINE_ITEMS', backup_value=True
+        )
+
     sku = serializers.CharField(
         source='part.SKU', read_only=True, allow_null=True, label=_('SKU')
     )

src/backend/InvenTree/order/test_api.py

@@ -1060,6 +1060,42 @@ class PurchaseOrderLineItemTest(OrderTest):
         ).json()
         self.assertEqual(float(li5['purchase_price']), 1)
 
+    def test_po_line_merge_default_setting(self):
+        """Test that merge_items defaults to the global setting value."""
+        self.assignRole('purchase_order.add')
+
+        su = Company.objects.get(pk=1)
+        sp = SupplierPart.objects.get(pk=1)
+        po = models.PurchaseOrder.objects.create(
+            supplier=su, reference='PO-MERGE-DEFAULT'
+        )
+
+        set_global_setting('PURCHASEORDER_MERGE_LINE_ITEMS', False)
+
+        li1 = self.post(
+            reverse('api-po-line-list'),
+            {'order': po.pk, 'part': sp.pk, 'quantity': 1},
+            expected_code=201,
+        ).json()
+
+        li2 = self.post(
+            reverse('api-po-line-list'),
+            {'order': po.pk, 'part': sp.pk, 'quantity': 2},
+            expected_code=201,
+        ).json()
+
+        self.assertNotEqual(li1['pk'], li2['pk'])
+
+        set_global_setting('PURCHASEORDER_MERGE_LINE_ITEMS', True)
+
+        li3 = self.post(
+            reverse('api-po-line-list'),
+            {'order': po.pk, 'part': sp.pk, 'quantity': 3},
+            expected_code=201,
+        ).json()
+
+        self.assertEqual(li1['pk'], li3['pk'])
+
     def test_output_options(self):
         """Test PurchaseOrderLineItem output option endpoint."""
         self.run_output_test(

src/frontend/src/components/wizards/OrderPartsWizard.tsx

@@ -32,6 +32,7 @@ import { usePurchaseOrderFields } from '../../forms/PurchaseOrderForms';
 import { useCreateApiFormModal } from '../../hooks/UseForm';
 import { useInstance } from '../../hooks/UseInstance';
 import useWizard from '../../hooks/UseWizard';
+import { useGlobalSettingsState } from '../../states/SettingsStates';
 import RemoveRowButton from '../buttons/RemoveRowButton';
 import { StandaloneField } from '../forms/StandaloneField';
 import Expand from '../items/Expand';
@@ -195,6 +196,7 @@ function SelectPartsStep({
   const [selectedRecord, setSelectedRecord] = useState<PartOrderRecord | null>(
     null
   );
+  const globalSettings = useGlobalSettingsState();
 
   const purchaseOrderFields = usePurchaseOrderFields({
     supplierId: selectedRecord?.supplier_part?.supplier
@@ -240,9 +242,11 @@ function SelectPartsStep({
       },
       purchase_price: {},
       purchase_price_currency: {},
-      merge_items: {}
+      merge_items: {
+        default: globalSettings.isSet('PURCHASEORDER_MERGE_LINE_ITEMS', true)
+      }
     };
-  }, [selectedRecord]);
+  }, [selectedRecord, globalSettings]);
 
   const addToOrder = useCreateApiFormModal({
     url: apiUrl(ApiEndpoints.purchase_order_line_list),

src/frontend/src/forms/PurchaseOrderForms.tsx

@@ -220,7 +220,9 @@ export function usePurchaseOrderLineItemFields({
     }
 
     if (create) {
-      fields['merge_items'] = {};
+      fields['merge_items'] = {
+        default: globalSettings.isSet('PURCHASEORDER_MERGE_LINE_ITEMS', true)
+      };
     }
 
     return fields;