Refs #373 -- Updated TupleIsNull lookup to check if any is NULL rather than all.

Regression in 1eac690d25dd49088256954d4046813daa37dc95.

3 files changed, 39 insertions, 15 deletions

diff --git a/django/db/models/fields/tuple_lookups.py b/django/db/models/fields/tuple_lookups.py
index 04c53944dc..cdb3b47209 100644
--- a/django/db/models/fields/tuple_lookups.py
+++ b/django/db/models/fields/tuple_lookups.py
@@ -57,18 +57,25 @@ class TupleExact(TupleLookupMixin, Exact):
         return root.as_sql(compiler, connection)
 
 
-class TupleIsNull(IsNull):
+class TupleIsNull(TupleLookupMixin, IsNull):
+    def get_prep_lookup(self):
+        rhs = self.rhs
+        if isinstance(rhs, (tuple, list)) and len(rhs) == 1:
+            rhs = rhs[0]
+        if isinstance(rhs, bool):
+            return rhs
+        raise ValueError(
+            "The QuerySet value for an isnull lookup must be True or False."
+        )
+
     def as_sql(self, compiler, connection):
         # e.g.: (a, b, c) is None as SQL:
-        # WHERE a IS NULL AND b IS NULL AND c IS NULL
-        vals = self.rhs
-        if isinstance(vals, bool):
-            vals = [vals] * len(self.lhs)
-
-        cols = self.lhs.get_cols()
-        lookups = [IsNull(col, val) for col, val in zip(cols, vals)]
-        root = WhereNode(lookups, connector=AND)
-
+        # WHERE a IS NULL OR b IS NULL OR c IS NULL
+        # e.g.: (a, b, c) is not None as SQL:
+        # WHERE a IS NOT NULL AND b IS NOT NULL AND c IS NOT NULL
+        rhs = self.rhs
+        lookups = [IsNull(col, rhs) for col in self.lhs]
+        root = WhereNode(lookups, connector=OR if rhs else AND)
         return root.as_sql(compiler, connection)
 
 
diff --git a/tests/foreign_object/models/person.py b/tests/foreign_object/models/person.py
index 33063e728a..f0848e6c3e 100644
--- a/tests/foreign_object/models/person.py
+++ b/tests/foreign_object/models/person.py
@@ -49,7 +49,7 @@ class Group(models.Model):
 
 class Membership(models.Model):
     # Table Column Fields
-    membership_country = models.ForeignKey(Country, models.CASCADE)
+    membership_country = models.ForeignKey(Country, models.CASCADE, null=True)
     date_joined = models.DateTimeField(default=datetime.datetime.now)
     invite_reason = models.CharField(max_length=64, null=True)
     person_id = models.IntegerField()
diff --git a/tests/foreign_object/tests.py b/tests/foreign_object/tests.py
index 89ed85b658..e288ecd7d4 100644
--- a/tests/foreign_object/tests.py
+++ b/tests/foreign_object/tests.py
@@ -516,18 +516,35 @@ class MultiColumnFKTests(TestCase):
 
     def test_isnull_lookup(self):
         m1 = Membership.objects.create(
-            membership_country=self.usa, person=self.bob, group_id=None
+            person_id=self.bob.id,
+            membership_country_id=self.usa.id,
+            group_id=None,
         )
         m2 = Membership.objects.create(
-            membership_country=self.usa, person=self.bob, group=self.cia
+            person_id=self.jim.id,
+            membership_country_id=None,
+            group_id=self.cia.id,
+        )
+        m3 = Membership.objects.create(
+            person_id=self.jane.id,
+            membership_country_id=None,
+            group_id=None,
+        )
+        m4 = Membership.objects.create(
+            person_id=self.george.id,
+            membership_country_id=self.soviet_union.id,
+            group_id=self.kgb.id,
         )
+        for member in [m1, m2, m3]:
+            with self.assertRaises(Membership.group.RelatedObjectDoesNotExist):
+                getattr(member, "group")
         self.assertSequenceEqual(
             Membership.objects.filter(group__isnull=True),
-            [m1],
+            [m1, m2, m3],
         )
         self.assertSequenceEqual(
             Membership.objects.filter(group__isnull=False),
-            [m2],
+            [m4],
         )