Fixed #7076 -- Include NULL values when excluding non-NULL items.

Based on a patch from emulbreh.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7760 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/query.py

@@ -1045,17 +1045,27 @@ class Query(object):
                 self.promote_alias(table)
 
         self.where.add((alias, col, field, lookup_type, value), connector)
+
         if negate:
             for alias in join_list:
                 self.promote_alias(alias)
-            if final > 1 and lookup_type != 'isnull':
+            if lookup_type != 'isnull':
+                if final > 1:
                     for alias in join_list:
-                    if self.alias_map[alias] == self.LOUTER:
+                        if self.alias_map[alias][JOIN_TYPE] == self.LOUTER:
                             j_col = self.alias_map[alias][RHS_JOIN_COL]
                             entry = Node([(alias, j_col, None, 'isnull', True)])
                             entry.negate()
                             self.where.add(entry, AND)
                             break
+                elif not (lookup_type == 'in' and not value):
+                    # Leaky abstraction artifact: We have to specifically
+                    # exclude the "foo__in=[]" case from this handling, because
+                    # it's short-circuited in the Where class.
+                    entry = Node([(alias, col, field, 'isnull', True)])
+                    entry.negate()
+                    self.where.add(entry, AND)
+
         if can_reuse is not None:
             can_reuse.update(join_list)
 

tests/regressiontests/queries/models.py

@@ -756,5 +756,11 @@ select_related(). We used to return the parent's Detail record here by mistake.
 >>> obj.person.details.data
 u'd2'
 
+Bug #7076 -- excluding shouldn't eliminate NULL entries.
+>>> Item.objects.exclude(modified=time1).order_by('name')
+[<Item: four>, <Item: three>, <Item: two>]
+>>> Tag.objects.exclude(parent__name=t1.name)
+[<Tag: t1>, <Tag: t4>, <Tag: t5>]
+
 """}