Improved table join handling for comparisons against NULL.

This fixes a broad class of bugs involving filters that look for missing
related models and fields. Most of them don't seem to have been reported
(the added tests cover the root cause). The exception is that this has
also fixed #9868.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9979 bcc190cf-cafb-0310-a4f2-bffc1f526a37

2 files changed, 45 insertions, 0 deletions

diff --git a/tests/regressiontests/null_queries/models.py b/tests/regressiontests/null_queries/models.py
index df04f14eba..7cde0aac61 100644
--- a/tests/regressiontests/null_queries/models.py
+++ b/tests/regressiontests/null_queries/models.py
@@ -13,6 +13,17 @@ class Choice(models.Model):
     def __unicode__(self):
         return u"Choice: %s in poll %s" % (self.choice, self.poll)
 
+# A set of models with an inner one pointing to two outer ones.
+class OuterA(models.Model):
+    pass
+
+class OuterB(models.Model):
+    data = models.CharField(max_length=10)
+
+class Inner(models.Model):
+    first = models.ForeignKey(OuterA)
+    second = models.ForeignKey(OuterB, null=True)
+
 __test__ = {'API_TESTS':"""
 # Regression test for the use of None as a query value. None is interpreted as
 # an SQL NULL, but only in __exact queries.
@@ -56,4 +67,16 @@ ValueError: Cannot use None as a query value
 >>> p2.choice_set.all()
 []
 
+# Querying across reverse relations and then another relation should insert
+# outer joins correctly so as not to exclude results.
+>>> obj = OuterA.objects.create()
+>>> OuterA.objects.filter(inner__second=None)
+[<OuterA: OuterA object>]
+>>> OuterA.objects.filter(inner__second__data=None)
+[<OuterA: OuterA object>]
+>>> _ = Inner.objects.create(first=obj)
+>>> Inner.objects.filter(first__inner__second=None)
+[<Inner: Inner object>]
+
+
 """}
diff --git a/tests/regressiontests/one_to_one_regress/models.py b/tests/regressiontests/one_to_one_regress/models.py
index 66d00d7223..5c89c55f45 100644
--- a/tests/regressiontests/one_to_one_regress/models.py
+++ b/tests/regressiontests/one_to_one_regress/models.py
@@ -33,6 +33,15 @@ class Favorites(models.Model):
     def __unicode__(self):
         return u"Favorites for %s" % self.name
 
+class Target(models.Model):
+    pass
+
+class Pointer(models.Model):
+    other = models.OneToOneField(Target, primary_key=True)
+
+class Pointer2(models.Model):
+    other = models.OneToOneField(Target)
+
 __test__ = {'API_TESTS':"""
 # Regression test for #1064 and #1506: Check that we create models via the m2m
 # relation if the remote model has a OneToOneField.
@@ -119,4 +128,17 @@ False
 >>> r.place == p
 True
 
+# Regression test for #9968: filtering reverse one-to-one relations with
+# primary_key=True was misbehaving. We test both (primary_key=True & False)
+# cases here to prevent any reappearance of the problem.
+>>> _ = Target.objects.create()
+>>> Target.objects.filter(pointer=None)
+[<Target: Target object>]
+>>> Target.objects.exclude(pointer=None)
+[]
+>>> Target.objects.filter(pointer2=None)
+[<Target: Target object>]
+>>> Target.objects.exclude(pointer2=None)
+[]
+
 """}