Sales Order Allocation Improvements (#4556)

* Do not remove sales order allocations when returning an item against a return order

* Also do not clear allocations when returning manually

* stock item display tweaks

* Add extra column to sales order allocation table

* Improve methods for introspecting sales order allocations for stockitems

* Only display "active" sales order allocations on a stock item detail page

- All allocations are still visible in the allocation table

* Can't have available quantity if you're not available

tap's side of nose

InvenTree/stock/models.py

@@ -33,7 +33,8 @@ from InvenTree.fields import (InvenTreeModelMoneyField, InvenTreeNotesField,
                               InvenTreeURLField)
 from InvenTree.models import (InvenTreeAttachment, InvenTreeBarcodeMixin,
                               InvenTreeTree, extract_int)
-from InvenTree.status_codes import StockHistoryCode, StockStatus
+from InvenTree.status_codes import (SalesOrderStatus, StockHistoryCode,
+                                    StockStatus)
 from part import models as PartModels
 from plugin.events import trigger_event
 from plugin.models import MetadataMixin
@@ -1013,7 +1014,6 @@ class StockItem(InvenTreeBarcodeMixin, MetadataMixin, common.models.MetaMixin, M
             location=location
         )
 
-        self.clearAllocations()
         self.customer = None
         self.belongs_to = None
         self.sales_order = None
@@ -1059,9 +1059,33 @@ class StockItem(InvenTreeBarcodeMixin, MetadataMixin, common.models.MetaMixin, M
 
         return total
 
-    def sales_order_allocation_count(self):
+    def get_sales_order_allocations(self, active=True):
+        """Return a queryset for SalesOrderAllocations against this StockItem, with optional filters.
+
+        Arguments:
+            active: Filter by 'active' status of the allocation
+        """
+        query = self.sales_order_allocations.all()
+
+        if active is True:
+            query = query.filter(
+                line__order__status__in=SalesOrderStatus.OPEN,
+                shipment__shipment_date=None
+            )
+        elif active is False:
+            query = query.exclude(
+                line__order__status__in=SalesOrderStatus.OPEN
+            ).exclude(
+                shipment__shipment_date=None
+            )
+
+        return query
+
+    def sales_order_allocation_count(self, active=True):
         """Return the total quantity allocated to SalesOrders."""
-        query = self.sales_order_allocations.aggregate(q=Coalesce(Sum('quantity'), Decimal(0)))
+
+        query = self.get_sales_order_allocations(active=active)
+        query = query.aggregate(q=Coalesce(Sum('quantity'), Decimal(0)))
 
         total = query['q']