More work

- Consolidated "in_stock" filter to single code location
- Improve 'limit_choices_to' for BuildItem and SalesOrderAllocation
- Various template improvements etc

InvenTree/order/migrations/0030_auto_20200426_0551.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.0.5 on 2020-04-26 05:51
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0033_auto_20200426_0539'),
+        ('order', '0029_auto_20200423_1042'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='salesorderallocation',
+            name='item',
+            field=models.ForeignKey(help_text='Select stock item to allocate', limit_choices_to={'belongs_to': None, 'build_order': None, 'customer': None, 'part__salable': True}, on_delete=django.db.models.deletion.CASCADE, related_name='sales_order_allocations', to='stock.StockItem'),
+        ),
+    ]

InvenTree/order/migrations/0031_auto_20200426_0612.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.0.5 on 2020-04-26 06:12
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0034_auto_20200426_0602'),
+        ('order', '0030_auto_20200426_0551'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='salesorderallocation',
+            name='item',
+            field=models.ForeignKey(help_text='Select stock item to allocate', limit_choices_to={'belongs_to': None, 'build_order': None, 'part__salable': True, 'sales_order': None}, on_delete=django.db.models.deletion.CASCADE, related_name='sales_order_allocations', to='stock.StockItem'),
+        ),
+    ]

InvenTree/order/models.py

@@ -19,7 +19,7 @@ import os
 from datetime import datetime
 from decimal import Decimal
 
-from part.models import Part
+from part import models as PartModels
 from stock import models as stock_models
 from company.models import Company, SupplierPart
 
@@ -511,7 +511,7 @@ class SalesOrderAllocation(models.Model):
         try:
             if not self.line.part == self.item.part:
                 errors['item'] = _('Cannot allocate stock item to a line with a different part')
-        except Part.DoesNotExist:
+        except PartModels.Part.DoesNotExist:
             errors['line'] = _('Cannot allocate stock to a line without a part')
 
         if self.quantity > self.item.quantity:
@@ -535,7 +535,12 @@ class SalesOrderAllocation(models.Model):
         'stock.StockItem',
         on_delete=models.CASCADE,
         related_name='sales_order_allocations',
-        limit_choices_to={'part__salable': True},
+        limit_choices_to={
+            'part__salable': True,
+            'belongs_to': None,
+            'sales_order': None,
+            'build_order': None,
+        },
         help_text=_('Select stock item to allocate')
     )
 
@@ -565,6 +570,8 @@ class SalesOrderAllocation(models.Model):
         - Mark the StockItem as belonging to the Customer (this will remove it from stock)
         """
 
+        order = self.line.order
+
         item = self.item
 
         # If the allocated quantity is less than the amount available,
@@ -579,7 +586,7 @@ class SalesOrderAllocation(models.Model):
             self.save()
 
         # Assign the StockItem to the SalesOrder customer
-        item.customer = self.line.order.customer
+        item.sales_order = order
 
         # Clear the location
         item.location = None