feat(model): res position unique index;

- Create a unique index for active resource positions.

Author: JVickery-TBS

ckan/lib/dictization/model_save.py

@@ -138,6 +138,7 @@ def package_resource_list_save(
     # Mark any left-over resources as deleted
     for resource in set(old_list) - set(obj_list):
         resource.state = 'deleted'
+        resource.position = None
         resource_list.append(resource)
 
     return True

ckan/migration/versions/109_e12e991f586b_create_res_position_constraint.py

@@ -1,6 +1,8 @@
 """Create con_package_resource_unique_position constraint
 to make resource positions unique per package.
 
+Sets deleted resource positions to null.
+
 Revision ID: e12e991f586b
 Revises: f7b64c701a10
 Create Date: 2026-02-10 18:26:31.122945
@@ -18,6 +20,11 @@
 
 
 def upgrade():
+    op.execute("""
+        UPDATE resource SET position=null WHERE state='deleted';
+    """)
+    print('Set position=null for deleted resources.')
+
     op.create_unique_constraint(
         constraint_name='con_package_resource_unique_position',
         table_name='resource', columns=['package_id', 'position'],

ckan/model/resource.py

@@ -2,7 +2,7 @@
 from __future__ import annotations
 
 import datetime
-from typing import Any, Callable, ClassVar, Optional, cast
+from typing import Any, Callable, ClassVar, Optional, List, cast
 
 
 from collections import OrderedDict
@@ -174,13 +174,29 @@ def related_packages(self) -> list[Package]:
 
 ## Mappers
 
+def _get_stately_resource_position(
+        index: int, resources: List[Resource]) -> Optional[int]:
+    """
+    Give state='deleted' resources null positions.
+
+    Required for con_package_resource_unique_position
+    unique constraint when deleting resources.
+    """
+    if resources[index].state != 'deleted':
+        return index
+    else:
+        return None
+
+
 meta.registry.map_imperatively(Resource, resource_table, properties={
     'package': orm.relationship(
         Package,
         # all resources including deleted
         # formally package_resources_all
         backref=orm.backref('resources_all',
-                            collection_class=ordering_list('position'),
+                            collection_class=ordering_list(
+                                'position',
+                                ordering_func=_get_stately_resource_position),
                             cascade='all, delete'
                             ),
     )

ckan/tests/logic/action/test_delete.py

@@ -33,6 +33,7 @@ def test_resource_delete(self):
         # It is still there but with state=deleted
         res_obj = model.Resource.get(resource["id"])
         assert res_obj.state == "deleted"
+        assert res_obj.position is None
 
     def test_resource_delete_for_delete(self):