Default receive location (#12911)

* Add global setting

* docs

* Dynamically set API field default

* UI elements

* regression testing

* Add CHANGELOG entry

* Fix unit test

src/backend/InvenTree/InvenTree/metadata.py

@@ -422,7 +422,14 @@ class InvenTreeMetadata(SimpleMetadata):
 
         # If a default value is specified for the serializer field, add it!
         if 'default' not in field_info and field.default != empty:
-            field_info['default'] = field.get_default()
+            default = field.get_default()
+
+            # Related fields resolve their default to a model instance,
+            # which is not JSON serializable - reduce it to its primitive representation
+            if isinstance(field, serializers.RelatedField) and default is not None:
+                default = field.to_representation(default)
+
+            field_info['default'] = default
 
         # Force non-nullable fields to read as "required"
         # (even if there is a default value!)

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

@@ -1031,6 +1031,15 @@ SYSTEM_SETTINGS: dict[str, InvenTreeSettingsKeyType] = {
         'default': True,
         'validator': bool,
     },
+    'PURCHASEORDER_DEFAULT_RECEIVE_LOCATION': {
+        'name': _('Default Receive Location'),
+        'description': _(
+            'Default destination location for received goods on new purchase orders'
+        ),
+        'default': '',
+        'model': 'stock.stocklocation',
+        'model_filters': {'structural': False},
+    },
     # login / SSO
     'LOGIN_ENABLE_PWD_FORGOT': {
         'name': _('Enable password forgot'),

src/backend/InvenTree/common/tests.py

@@ -503,6 +503,8 @@ class SettingsTest(InvenTreeTestCase):
             'hidden',
             'choices',
             'units',
+            'model',
+            'model_filters',
             'requires_restart',
             'after_save',
             'before_save',

src/backend/InvenTree/order/serializers.py

@@ -420,6 +420,22 @@ class PurchaseOrderSerializer(
 
         return [*fields, 'duplicate']
 
+    def __init__(self, *args, **kwargs):
+        """Set a dynamic default for the 'destination' field, on creation only."""
+        super().__init__(*args, **kwargs)
+
+        if self.instance is None:
+            location_pk = get_global_setting(
+                'PURCHASEORDER_DEFAULT_RECEIVE_LOCATION', backup_value=None
+            )
+
+            if location_pk:
+                self.fields[
+                    'destination'
+                ].default = stock.models.StockLocation.objects.filter(
+                    pk=location_pk
+                ).first()
+
     duplicate = DuplicateOptionsSerializer(
         order.models.PurchaseOrder.objects.all(),
         copy_lines=True,

src/backend/InvenTree/order/test_api.py

@@ -527,6 +527,53 @@ class PurchaseOrderTest(OrderTest):
         # Revert the setting to previous value
         InvenTreeSetting.set_setting(setting, False)
 
+    def test_po_create_default_destination(self):
+        """Test that the PURCHASEORDER_DEFAULT_RECEIVE_LOCATION setting is applied on creation."""
+        self.assignRole('purchase_order.add')
+
+        url = reverse('api-po-list')
+        location = StockLocation.objects.first()
+        assert location
+
+        # By default, no destination is set on the setting - so the field is left blank
+        set_global_setting('PURCHASEORDER_DEFAULT_RECEIVE_LOCATION', '')
+
+        data = {
+            'reference': 'PO-99990001',
+            'supplier': 1,
+            'description': 'A test purchase order',
+        }
+
+        response = self.post(url, data, expected_code=201)
+        self.assertIsNone(response.data['destination'])
+
+        # Now, set the global default - newly created orders should inherit it
+        set_global_setting('PURCHASEORDER_DEFAULT_RECEIVE_LOCATION', location.pk)
+
+        # The OPTIONS metadata for the 'destination' field should reflect the default location
+        response = self.options(url, expected_code=200)
+        self.assertEqual(
+            response.data['actions']['POST']['destination']['default'], location.pk
+        )
+
+        data['reference'] = 'PO-99990002'
+
+        response = self.post(url, data, expected_code=201)
+        self.assertEqual(response.data['destination'], location.pk)
+
+        # An explicitly provided destination should always take priority
+        other_location = StockLocation.objects.exclude(pk=location.pk).first()
+        assert other_location
+
+        data['reference'] = 'PO-99990003'
+        data['destination'] = other_location.pk
+
+        response = self.post(url, data, expected_code=201)
+        self.assertEqual(response.data['destination'], other_location.pk)
+
+        # Revert the setting to its previous value
+        set_global_setting('PURCHASEORDER_DEFAULT_RECEIVE_LOCATION', '')
+
     def test_po_creation_date(self):
         """Test that we can create set the creation_date field of PurchaseOrder via the API."""
         self.assignRole('purchase_order.add')