Ticket #11789: 11789.diff

django/db/models/query.py

@@ -1105 +1105 @@
         Don't update anything.
         """
         return 0
+    
+    def aggregate(self, *args, **kwargs):
+        """
+        Returns a dict mapping the aggregate names to None
+        """
+        for arg in args:
+            kwargs[arg.default_alias] = arg
+        return dict([(key, None) for key in kwargs])
 
     # EmptyQuerySet is always an empty result in where-clauses (and similar
     # situations).

tests/regressiontests/aggregation_regress/models.py

@@ -318 +318 @@
 ...
 FieldError: Cannot compute Avg('mean_age'): 'mean_age' is an aggregate
 
+# Regression for 11789 - Aggregates ignore none()
+>>> Author.objects.none().aggregate(Avg('age'))
+{'age__avg': None}
+
 """
 }