Fixed #21552 -- Allowed the use of None for the iexact lookup.

Thanks Anubhav Joshi for the documentation.

django/db/models/sql/query.py

@@ -1031,7 +1031,7 @@ class Query(object):
         # Interpret '__exact=None' as the sql 'is NULL'; otherwise, reject all
         # uses of None as a query value.
         if value is None:
-            if lookup_type != 'exact':
+            if lookup_type not in ('exact', 'iexact'):
                 raise ValueError("Cannot use None as a query value")
             lookup_type = 'isnull'
             value = True

docs/ref/models/querysets.txt

@@ -2028,9 +2028,15 @@ iexact
 
 Case-insensitive exact match.
 
+.. versionchanged:: 1.7
+
+    If the value provided for comparision is ``None``, it will be interpreted
+    as an SQL ``NULL`` (see :lookup:`isnull` for more details).
+
 Example::
 
     Blog.objects.get(name__iexact='beatles blog')
+    Blog.objects.get(name__iexact=None)
 
 SQL equivalent::
 

docs/releases/1.7.txt

@@ -450,6 +450,9 @@ Models
   argument to control whether or not to perform operations in bulk
   (i.e. using ``QuerySet.update()``). Defaults to ``True``.
 
+* It is now possible to use ``None`` as a query value for the :lookup:`iexact`
+  lookup.
+
 Signals
 ^^^^^^^
 

tests/null_queries/tests.py

@@ -12,7 +12,8 @@ class NullQueriesTests(TestCase):
         """
         Regression test for the use of None as a query value.
 
-        None is interpreted as an SQL NULL, but only in __exact queries.
+        None is interpreted as an SQL NULL, but only in __exact and __iexact
+        queries.
         Set up some initial polls and choices
         """
         p1 = Poll(question='Why?')
@@ -26,6 +27,9 @@ class NullQueriesTests(TestCase):
         # but every 'id' field has a value).
         self.assertQuerysetEqual(Choice.objects.filter(choice__exact=None), [])
 
+        # The same behavior for iexact query.
+        self.assertQuerysetEqual(Choice.objects.filter(choice__iexact=None), [])
+
         # Excluding the previous result returns everything.
         self.assertQuerysetEqual(
             Choice.objects.exclude(choice=None).order_by('id'),
@@ -38,10 +42,10 @@ class NullQueriesTests(TestCase):
         # Valid query, but fails because foo isn't a keyword
         self.assertRaises(FieldError, Choice.objects.filter, foo__exact=None)
 
-        # Can't use None on anything other than __exact
+        # Can't use None on anything other than __exact and __iexact
         self.assertRaises(ValueError, Choice.objects.filter, id__gt=None)
 
-        # Can't use None on anything other than __exact
+        # Can't use None on anything other than __exact and __iexact
         self.assertRaises(ValueError, Choice.objects.filter, foo__gt=None)
 
         # Related managers use __exact=None implicitly if the object hasn't been saved.