Virtual part fix (#3265)

* Add 'virtual': False requirement to sales order items

* Adds "virtual" filter for part table

* Adds extra validation to the SalesOrderLineItem model

* Prevent creation of stock items for virtual parts

- Add validation check to clean() method of StockItem model
- Improve validation message for StockItemSerializer class

* Hide "new stock item" button for virtual parts

* Hide more buttons for 'virtual' parts

InvenTree/order/migrations/0071_auto_20220628_0133.py

@@ -0,0 +1,26 @@
+# Generated by Django 3.2.13 on 2022-06-28 01:33
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0077_alter_stockitem_notes'),
+        ('part', '0079_alter_part_notes'),
+        ('order', '0070_auto_20220620_0728'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='salesorderallocation',
+            name='item',
+            field=models.ForeignKey(help_text='Select stock item to allocate', limit_choices_to={'belongs_to': None, 'part__salable': True, 'part__virtual': False, 'sales_order': None}, on_delete=django.db.models.deletion.CASCADE, related_name='sales_order_allocations', to='stock.stockitem', verbose_name='Item'),
+        ),
+        migrations.AlterField(
+            model_name='salesorderlineitem',
+            name='part',
+            field=models.ForeignKey(help_text='Part', limit_choices_to={'salable': True, 'virtual': False}, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='sales_order_line_items', to='part.part', verbose_name='Part'),
+        ),
+    ]

InvenTree/order/models.py

@@ -1103,6 +1103,22 @@ class SalesOrderLineItem(OrderLineItem):
         """Return the API URL associated with the SalesOrderLineItem model"""
         return reverse('api-so-line-list')
 
+    def clean(self):
+        """Perform extra validation steps for this SalesOrderLineItem instance"""
+
+        super().clean()
+
+        if self.part:
+            if self.part.virtual:
+                raise ValidationError({
+                    'part': _("Virtual part cannot be assigned to a sales order")
+                })
+
+            if not self.part.salable:
+                raise ValidationError({
+                    'part': _("Only salable parts can be assigned to a sales order")
+                })
+
     order = models.ForeignKey(
         SalesOrder,
         on_delete=models.CASCADE,
@@ -1111,7 +1127,16 @@ class SalesOrderLineItem(OrderLineItem):
         help_text=_('Sales Order')
     )
 
-    part = models.ForeignKey('part.Part', on_delete=models.SET_NULL, related_name='sales_order_line_items', null=True, verbose_name=_('Part'), help_text=_('Part'), limit_choices_to={'salable': True})
+    part = models.ForeignKey(
+        'part.Part', on_delete=models.SET_NULL,
+        related_name='sales_order_line_items',
+        null=True,
+        verbose_name=_('Part'),
+        help_text=_('Part'),
+        limit_choices_to={
+            'salable': True,
+            'virtual': False,
+        })
 
     sale_price = InvenTreeModelMoneyField(
         max_digits=19,
@@ -1409,6 +1434,7 @@ class SalesOrderAllocation(models.Model):
         related_name='sales_order_allocations',
         limit_choices_to={
             'part__salable': True,
+            'part__virtual': False,
             'belongs_to': None,
             'sales_order': None,
         },