Merge pull request #813 from HiddenData/ticket-19263

fixes #19263 - EmptyResultSet in subquery causes incorrect SQL

django/db/models/sql/where.py

@@ -204,6 +204,10 @@ class WhereNode(tree.Node):
                 raise EmptyResultSet
             if extra:
                 return ('%s IN %s' % (field_sql, extra), params)
+            if not params:
+                # Empty params would generate invalid sql in subquery
+                raise EmptyResultSet
+
             max_in_list_size = connection.ops.max_in_list_size()
             if max_in_list_size and len(params) > max_in_list_size:
                 # Break up the params list into an OR of manageable chunks.

tests/regressiontests/queries/tests.py

@@ -2021,6 +2021,9 @@ class WeirdQuerysetSlicingTests(BaseQuerysetTest):
         Article.objects.create(name='three', created=datetime.datetime.now())
         Article.objects.create(name='four', created=datetime.datetime.now())
 
+        food = Food.objects.create(name='spam')
+        Eaten.objects.create(meal='spam with eggs', food=food)
+
     def test_tickets_7698_10202(self):
         # People like to slice with '0' as the high-water mark.
         self.assertQuerysetEqual(Article.objects.all()[0:0], [])
@@ -2036,6 +2039,18 @@ class WeirdQuerysetSlicingTests(BaseQuerysetTest):
         # ticket #12192
         self.assertNumQueries(0, lambda: list(Number.objects.all()[1:1]))
 
+    def test_empty_sliced_subquery(self):
+        # ticket #19263 - testing subqueries
+        self.assertEqual(
+            Eaten.objects.filter(food__in=Food.objects.all()[0:0]).count(),
+            0)
+
+    def test_empty_sliced_subquery_exclude(self):
+        # ticket #19263 - testing subqueries
+        self.assertEqual(
+            Eaten.objects.exclude(food__in=Food.objects.all()[0:0]).count(),
+            1)
+
 
 class EscapingTests(TestCase):
     def test_ticket_7302(self):