Fixed #14511 -- bug in .exclude() query

django/db/models/sql/datastructures.py

@@ -4,6 +4,21 @@ the SQL domain.
 """
 
 
+class Col(object):
+    def __init__(self, alias, col):
+        self.alias = alias
+        self.col = col
+
+    def as_sql(self, qn, connection):
+        return '%s.%s' % (qn(self.alias), self.col), []
+
+    def prepare(self):
+        return self
+
+    def relabeled_clone(self, relabels):
+        return self.__class__(relabels.get(self.alias, self.alias), self.col)
+
+
 class EmptyResultSet(Exception):
     pass
 

django/db/models/sql/query.py

@@ -22,7 +22,7 @@ from django.db.models.related import PathInfo
 from django.db.models.sql import aggregates as base_aggregates_module
 from django.db.models.sql.constants import (QUERY_TERMS, ORDER_DIR, SINGLE,
         ORDER_PATTERN, JoinInfo, SelectInfo)
-from django.db.models.sql.datastructures import EmptyResultSet, Empty, MultiJoin
+from django.db.models.sql.datastructures import EmptyResultSet, Empty, MultiJoin, Col
 from django.db.models.sql.expressions import SQLEvaluator
 from django.db.models.sql.where import (WhereNode, Constraint, EverythingNode,
     ExtraWhere, AND, OR, EmptyWhere)
@@ -820,6 +820,9 @@ class Query(object):
         conflict. Even tables that previously had no alias will get an alias
         after this call.
         """
+        if self.alias_prefix != outer_query.alias_prefix:
+            # No clashes between self and outer query should be possible.
+            return
         self.alias_prefix = chr(ord(self.alias_prefix) + 1)
         while self.alias_prefix in self.subq_aliases:
             self.alias_prefix = chr(ord(self.alias_prefix) + 1)
@@ -1514,9 +1517,19 @@ class Query(object):
         # since we are adding a IN <subquery> clause. This prevents the
         # database from tripping over IN (...,NULL,...) selects and returning
         # nothing
-        if self.is_nullable(query.select[0].field):
         alias, col = query.select[0].col
+        if self.is_nullable(query.select[0].field):
             query.where.add((Constraint(alias, col, query.select[0].field), 'isnull', False), AND)
+        if alias in can_reuse:
+            pk = query.select[0].field.model._meta.pk
+            # Need to add a restriction so that outer query's filters are in effect for
+            # the subquery, too.
+            query.bump_prefix(self)
+            query.where.add(
+                (Constraint(query.select[0].col[0], pk.column, pk),
+                 'exact', Col(alias, pk.column)),
+                AND
+            )
 
         condition = self.build_filter(
             ('%s__in' % trimmed_prefix, query),

tests/queries/models.py

@@ -544,3 +544,22 @@ class Ticket21203Parent(models.Model):
 class Ticket21203Child(models.Model):
     childid = models.AutoField(primary_key=True)
     parent = models.ForeignKey(Ticket21203Parent)
+
+
+class Person(models.Model):
+    name = models.CharField(max_length=128)
+
+
+@python_2_unicode_compatible
+class Company(models.Model):
+    name = models.CharField(max_length=128)
+    employees = models.ManyToManyField(Person, related_name='employers', through='Employment')
+
+    def __str__(self):
+        return self.name
+
+
+class Employment(models.Model):
+    employer = models.ForeignKey(Company)
+    employee = models.ForeignKey(Person)
+    title = models.CharField(max_length=128)

tests/queries/tests.py

@@ -25,7 +25,8 @@ from .models import (
     ModelA, ModelB, ModelC, ModelD, Responsibility, Job, JobResponsibilities,
     BaseA, FK1, Identifier, Program, Channel, Page, Paragraph, Chapter, Book,
     MyObject, Order, OrderItem, SharedConnection, Task, Staff, StaffUser,
-    CategoryRelationship, Ticket21203Parent, Ticket21203Child)
+    CategoryRelationship, Ticket21203Parent, Ticket21203Child, Person,
+    Company, Employment)
 
 class BaseQuerysetTest(TestCase):
     def assertValueQuerysetEqual(self, qs, values):
@@ -2352,7 +2353,7 @@ class DefaultValuesInsertTest(TestCase):
         except TypeError:
             self.fail("Creation of an instance of a model with only the PK field shouldn't error out after bulk insert refactoring (#17056)")
 
-class ExcludeTest(TestCase):
+class ExcludeTests(TestCase):
     def setUp(self):
         f1 = Food.objects.create(name='apples')
         Food.objects.create(name='oranges')
@@ -2375,6 +2376,37 @@ class ExcludeTest(TestCase):
             Responsibility.objects.exclude(jobs__name='Manager'),
             ['<Responsibility: Programming>'])
 
+    def test_ticket14511(self):
+        alex = Person.objects.get_or_create(name='Alex')[0]
+        jane = Person.objects.get_or_create(name='Jane')[0]
+
+        oracle = Company.objects.get_or_create(name='Oracle')[0]
+        google = Company.objects.get_or_create(name='Google')[0]
+        microsoft = Company.objects.get_or_create(name='Microsoft')[0]
+        intel = Company.objects.get_or_create(name='Intel')[0]
+
+        def employ(employer, employee, title):
+            Employment.objects.get_or_create(employee=employee, employer=employer, title=title)
+
+        employ(oracle, alex, 'Engineer')
+        employ(oracle, alex, 'Developer')
+        employ(google, alex, 'Engineer')
+        employ(google, alex, 'Manager')
+        employ(microsoft, alex, 'Manager')
+        employ(intel, alex, 'Manager')
+
+        employ(microsoft, jane, 'Developer')
+        employ(intel, jane, 'Manager')
+
+        alex_tech_employers = alex.employers.filter(
+            employment__title__in=('Engineer', 'Developer')).distinct().order_by('name')
+        self.assertQuerysetEqual(alex_tech_employers, [google, oracle], lambda x: x)
+
+        alex_nontech_employers = alex.employers.exclude(
+            employment__title__in=('Engineer', 'Developer')).distinct().order_by('name')
+        self.assertQuerysetEqual(alex_nontech_employers, [google, intel, microsoft], lambda x: x)
+
+
 class ExcludeTest17600(TestCase):
     """
     Some regressiontests for ticket #17600. Some of these likely duplicate
@@ -3135,3 +3167,6 @@ class ValuesJoinPromotionTests(TestCase):
     def test_non_nullable_fk_not_promoted(self):
         qs = ObjectB.objects.values('objecta__name')
         self.assertTrue(' INNER JOIN ' in str(qs.query))
+
+
+class ExcludeJoinTest(TestCase):