fixed 'source_expressions'

(cherry picked from commit 9a34a2a)
jazzband · Apr 8, 2015 · 135feaf · 135feaf
1 parent 6404612
commit 135feaf
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/polymorphic/query.py b/polymorphic/query.py
@@ -103,8 +103,9 @@ def patch_lookup(a):
             else:
                 # With Django > 1.8, the field on which the aggregate operates is
                 # stored inside a query expression.
-                a.source_expressions[0].name = translate_polymorphic_field_path(
-                    self.model, a.source_expressions[0].name)
+                if hasattr(a, 'source_expressions'):
+                    a.source_expressions[0].name = translate_polymorphic_field_path(
+                        self.model, a.source_expressions[0].name)
 
         get_lookup = lambda a: a.lookup if django.VERSION < (1, 8) else a.source_expressions[0].name