Bug premium sale

modules/purchase_trade/sale.py

@@ -509,7 +509,10 @@ class Sale(metaclass=PoolMeta):
     def _get_report_display_price_value(self, line):
         if getattr(line, 'price_type', None) == 'basis':
             if getattr(line, 'enable_linked_currency', False) and getattr(line, 'linked_currency', None):
-                return Decimal(str(line.premium or 0))
+                premium = getattr(line, 'premium', None)
+                if premium is None and hasattr(line, '_get_premium_price'):
+                    premium = line._get_premium_price()
+                return Decimal(str(premium or 0))
             return Decimal(str(line._get_premium_price() or 0))
         if getattr(line, 'linked_price', None):
             return Decimal(str(line.linked_price or 0))
@@ -1854,7 +1857,10 @@ class SaleLine(metaclass=PoolMeta):
                 }])
 
     def _get_premium_price(self):
-        return Decimal(self.premium or 0)
+        premium = getattr(self, 'premium', None)
+        if premium is None:
+            premium = self.get_premium('premium')
+        return Decimal(str(premium or 0))
 
     def _get_amount_quantity(self):
         if getattr(self, 'finished', False):

modules/purchase_trade/tests/test_module.py

@@ -2164,6 +2164,22 @@ class PurchaseTradeTestCase(ModuleTestCase):
 
         self.assertEqual(line.get_premium('premium'), Decimal('10.2500'))
 
+    def test_sale_line_premium_price_falls_back_to_decomposition(self):
+        'sale line premium price works when the function field is not loaded'
+        class LineWithoutPremium:
+            premium_decomposition = [
+                Mock(base_amount=Decimal('7.25')),
+                Mock(base_amount=Decimal('-1.00')),
+            ]
+
+            get_premium = sale_module.SaleLine.get_premium
+
+        line = LineWithoutPremium()
+
+        self.assertEqual(
+            sale_module.SaleLine._get_premium_price(line),
+            Decimal('6.2500'))
+
     def test_purchase_and_sale_line_premium_fields_are_readonly_totals(self):
         'line premium fields are readonly totals from premium decomposition'
         PurchaseLine = Pool().get('purchase.line')