Fixed #16409 -- Fixed an error condition when using QuerySet only()/defer() on the result of an annotate() call. Thanks jaklaassen AT gmail DOT com and Tai Lee for the reports and Tai for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16522 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -231,9 +231,6 @@ class QuerySet(object):
             fields = self.model._meta.fields
             pk_idx = self.model._meta.pk_index()
 
-        index_start = len(extra_select)
-        aggregate_start = index_start + len(self.model._meta.fields)
-
         load_fields = []
         # If only/defer clauses have been specified,
         # build the list of fields that are to be loaded.
@@ -253,6 +250,9 @@ class QuerySet(object):
                     # Therefore, we need to load all fields from this model
                     load_fields.append(field.name)
 
+        index_start = len(extra_select)
+        aggregate_start = index_start + len(load_fields or self.model._meta.fields)
+
         skip = None
         if load_fields and not fill_cache:
             # Some fields have been deferred, so we have to initialise