From 468d8211df999845607c3bb163c859e428d39dea Mon Sep 17 00:00:00 2001
From: rynomster <rmathee@gmail.com>
Date: Thu, 14 Jan 2016 10:26:44 +0200
Subject: [PATCH] Fixed #23971 -- Added "Has date"/"No date" choices for
 DateFieldListFilter.

---
 AUTHORS                         |  1 +
 django/contrib/admin/filters.py | 11 ++++++++++-
 docs/releases/1.10.txt          |  3 +++
 tests/admin_filters/tests.py    | 31 +++++++++++++++++++++++++++++++
 4 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 4d9fcaecf45..9e063a3df31 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -638,6 +638,7 @@ answer newbie questions, and generally made Django that much better:
     ryankanno
     Ryan Kelly <ryan@rfk.id.au>
     Ryan Niemeyer <https://profiles.google.com/ryan.niemeyer/about>
+    Ryno Mathee <rmathee@gmail.com>
     Sam Newman <http://www.magpiebrain.com/>
     Sander Dijkhuis <sander.dijkhuis@gmail.com>
     Sarthak Mehrish <sarthakmeh03@gmail.com>
diff --git a/django/contrib/admin/filters.py b/django/contrib/admin/filters.py
index af5ec34995d..b64cc9ca9e5 100644
--- a/django/contrib/admin/filters.py
+++ b/django/contrib/admin/filters.py
@@ -331,11 +331,20 @@ class DateFieldListFilter(FieldListFilter):
                 self.lookup_kwarg_until: str(next_year),
             }),
         )
+        if field.null:
+            self.lookup_kwarg_isnull = '%s__isnull' % field_path
+            self.links += (
+                (_('No date'), {self.field_generic + 'isnull': 'True'}),
+                (_('Has date'), {self.field_generic + 'isnull': 'False'}),
+            )
         super(DateFieldListFilter, self).__init__(
             field, request, params, model, model_admin, field_path)
 
     def expected_parameters(self):
-        return [self.lookup_kwarg_since, self.lookup_kwarg_until]
+        params = [self.lookup_kwarg_since, self.lookup_kwarg_until]
+        if self.field.null:
+            params.append(self.lookup_kwarg_isnull)
+        return params
 
     def choices(self, changelist):
         for title, param_dict in self.links:
diff --git a/docs/releases/1.10.txt b/docs/releases/1.10.txt
index a0419b76bc7..7a3643969b3 100644
--- a/docs/releases/1.10.txt
+++ b/docs/releases/1.10.txt
@@ -59,6 +59,9 @@ Minor features
 * Selected objects for fields in ``ModelAdmin.raw_id_fields`` now have a link
   to object's change form.
 
+* Added "No date" and "Has date" choices for ``DateFieldListFilter`` if the
+  field is nullable.
+
 :mod:`django.contrib.admindocs`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/tests/admin_filters/tests.py b/tests/admin_filters/tests.py
index 570353430d3..eb9d1e7fd74 100644
--- a/tests/admin_filters/tests.py
+++ b/tests/admin_filters/tests.py
@@ -402,6 +402,37 @@ class ListFiltersTests(TestCase):
             )
         )
 
+        # Null/not null queries
+        request = self.request_factory.get('/', {'date_registered__isnull': 'True'})
+        changelist = self.get_changelist(request, Book, modeladmin)
+
+        # Make sure the correct queryset is returned
+        queryset = changelist.get_queryset(request)
+        self.assertEqual(queryset.count(), 1)
+        self.assertEqual(queryset[0], self.bio_book)
+
+        # Make sure the correct choice is selected
+        filterspec = changelist.get_filters(request)[0][4]
+        self.assertEqual(force_text(filterspec.title), 'date registered')
+        choice = select_by(filterspec.choices(changelist), 'display', 'No date')
+        self.assertEqual(choice['selected'], True)
+        self.assertEqual(choice['query_string'], '?date_registered__isnull=True')
+
+        request = self.request_factory.get('/', {'date_registered__isnull': 'False'})
+        changelist = self.get_changelist(request, Book, modeladmin)
+
+        # Make sure the correct queryset is returned
+        queryset = changelist.get_queryset(request)
+        self.assertEqual(queryset.count(), 3)
+        self.assertEqual(list(queryset), [self.gipsy_book, self.django_book, self.djangonaut_book])
+
+        # Make sure the correct choice is selected
+        filterspec = changelist.get_filters(request)[0][4]
+        self.assertEqual(force_text(filterspec.title), 'date registered')
+        choice = select_by(filterspec.choices(changelist), 'display', 'Has date')
+        self.assertEqual(choice['selected'], True)
+        self.assertEqual(choice['query_string'], '?date_registered__isnull=False')
+
     @unittest.skipIf(
         sys.platform.startswith('win'),
         "Windows doesn't support setting a timezone that differs from the "