Improve deletion behaviour for InvenTreeTree model (#5806)

* Improve deletion behaviour for InvenTreeTree model

- Remove recursive call to function
- Handle database operations as bulk queries
- Ensure child nodes have their pathstring updated correctly
- Remove old @receiver hook
- Refactor StockLocation.delete method
- Refactor PartCategory.delete method
- Atomic transactions potentially problematic here

* Add docstring

* Fix method name

* Use bulk-update instead of recursive save when pathstring changes

* Improvements for tree delete method

- Handle case where item has already been deleted

* Raise exception rather than simply logging

* Update unit tests

* Improvements to unrelated unit test

* Fix urls.md

* Fix typo

InvenTree/stock/api.py

@@ -1418,13 +1418,19 @@ class LocationDetail(CustomRetrieveUpdateDestroyAPI):
 
     def destroy(self, request, *args, **kwargs):
         """Delete a Stock location instance via the API"""
-        delete_stock_items = 'delete_stock_items' in request.data and request.data['delete_stock_items'] == '1'
-        delete_sub_locations = 'delete_sub_locations' in request.data and request.data['delete_sub_locations'] == '1'
-        return super().destroy(request,
-                               *args,
-                               **dict(kwargs,
-                                      delete_sub_locations=delete_sub_locations,
-                                      delete_stock_items=delete_stock_items))
+
+        delete_stock_items = str(request.data.get('delete_stock_items', 0)) == '1'
+        delete_sub_locations = str(request.data.get('delete_sub_locations', 0)) == '1'
+
+        return super().destroy(
+            request,
+            *args,
+            **dict(
+                kwargs,
+                delete_sub_locations=delete_sub_locations,
+                delete_stock_items=delete_stock_items
+            )
+        )
 
 
 stock_api_urls = [

InvenTree/stock/models.py

@@ -108,6 +108,8 @@ class StockLocation(InvenTreeBarcodeMixin, MetadataMixin, InvenTreeTree):
     Stock locations can be hierarchical as required
     """
 
+    ITEM_PARENT_KEY = 'location'
+
     objects = StockLocationManager()
 
     class Meta:
@@ -118,51 +120,16 @@ class StockLocation(InvenTreeBarcodeMixin, MetadataMixin, InvenTreeTree):
 
     tags = TaggableManager(blank=True)
 
-    def delete_recursive(self, *args, **kwargs):
-        """This function handles the recursive deletion of sub-locations depending on kwargs contents"""
-        delete_stock_items = kwargs.get('delete_stock_items', False)
-        parent_location = kwargs.get('parent_location', None)
-
-        if parent_location is None:
-            # First iteration, (no parent_location kwargs passed)
-            parent_location = self.parent
-
-        for child_item in self.get_stock_items(False):
-            if delete_stock_items:
-                child_item.delete()
-            else:
-                child_item.location = parent_location
-                child_item.save()
-
-        for child_location in self.children.all():
-            if kwargs.get('delete_sub_locations', False):
-                child_location.delete_recursive(**{
-                    "delete_sub_locations": True,
-                    "delete_stock_items": delete_stock_items,
-                    "parent_location": parent_location})
-            else:
-                child_location.parent = parent_location
-                child_location.save()
-
-        super().delete(*args, **{})
-
     def delete(self, *args, **kwargs):
         """Custom model deletion routine, which updates any child locations or items.
 
         This must be handled within a transaction.atomic(), otherwise the tree structure is damaged
         """
-        with transaction.atomic():
 
-            self.delete_recursive(**{
-                "delete_stock_items": kwargs.get('delete_stock_items', False),
-                "delete_sub_locations": kwargs.get('delete_sub_locations', False),
-                "parent_category": self.parent})
-
-            if self.parent is not None:
-                # Partially rebuild the tree (cheaper than a complete rebuild)
-                StockLocation.objects.partial_rebuild(self.tree_id)
-            else:
-                StockLocation.objects.rebuild()
+        super().delete(
+            delete_children=kwargs.get('delete_sub_locations', False),
+            delete_items=kwargs.get('delete_stock_items', False),
+        )
 
     @staticmethod
     def get_api_url():
@@ -300,6 +267,10 @@ class StockLocation(InvenTreeBarcodeMixin, MetadataMixin, InvenTreeTree):
         """
         return self.stock_item_count()
 
+    def get_items(self, cascade=False):
+        """Return a queryset for all stock items under this category"""
+        return self.get_stock_items(cascade=cascade)
+
 
 def generate_batch_code():
     """Generate a default 'batch code' for a new StockItem.