Fix part deletion template

- Display list of stock items which will be thusly deleted

InvenTree/InvenTree/helpers.py

@@ -176,7 +176,7 @@ def ExtractSerialNumbers(serials, expected_quantity):
                 else:
                     numbers.append(n)
             except ValueError:
-                print("Invalid group: {g}".format(g=group))
+                errors.append("Invalid group: {g}".format(g=group))
 
     if len(errors) > 0:
         raise ValidationError(errors)

InvenTree/part/templates/part/partial_delete.html

@@ -16,12 +16,12 @@
 </p>
 {% endif %}
 
-{% if part.locations.all|length > 0 %}
+{% if part.stock_items.all|length > 0 %}
 <hr>
-<p>There are {{ part.locations.all|length }} stock entries defined for this part. If you delete this part, the following stock entries will also be deleted:
+<p>There are {{ part.stock_items.all|length }} stock entries defined for this part. If you delete this part, the following stock entries will also be deleted:
     <ul class='list-group'>
-        {% for stock in part.locations.all %}
-        <li class='list-group-item'>{{ stock.location.name }} - {{ stock.quantity }} items</li>
+        {% for stock in part.stock_items.all %}
+        <li class='list-group-item'>{{ stock }}</li>
         {% endfor %}
     </ul>
 </p>

InvenTree/stock/models.py

@@ -528,9 +528,14 @@ class StockItem(models.Model):
         return True
 
     def __str__(self):
-        s = '{n} x {part}'.format(
-            n=self.quantity,
-            part=self.part.full_name)
+        if self.part.trackable and self.serial:
+            s = '{part} #{sn}'.format(
+                part=self.part.full_name,
+                sn=self.serial)
+        else:
+            s = '{n} x {part}'.format(
+                n=self.quantity,
+                part=self.part.full_name)
 
         if self.location:
             s += ' @ {loc}'.format(loc=self.location.name)