Fixed #28082 -- Made BaseDateListView pass context from get_dated_items() to subclasses.

Thanks leon-matthews for the report and fix.

django/views/generic/dates.py

@@ -297,9 +297,11 @@ class BaseDateListView(MultipleObjectMixin, DateMixin, View):
 
     def get(self, request, *args, **kwargs):
         self.date_list, self.object_list, extra_context = self.get_dated_items()
-        context = self.get_context_data(object_list=self.object_list,
-                                        date_list=self.date_list)
-        context.update(extra_context)
+        context = self.get_context_data(
+            object_list=self.object_list,
+            date_list=self.date_list,
+            **extra_context
+        )
         return self.render_to_response(context)
 
     def get_dated_items(self):

tests/generic_views/test_dates.py

 import datetime
+from unittest import mock
 
 from django.core.exceptions import ImproperlyConfigured
 from django.test import TestCase, override_settings, skipUnlessDBFeature
@@ -274,6 +275,22 @@ class YearArchiveViewTests(TestDataMixin, TestCase):
         res = self.client.get('/dates/books/2011/')
         self.assertEqual(list(res.context['date_list']), list(sorted(res.context['date_list'])))
 
+    @mock.patch('django.views.generic.list.MultipleObjectMixin.get_context_data')
+    def test_get_context_data_receives_extra_context(self, mock):
+        """
+        MultipleObjectMixin.get_context_data() receives the context set by
+        BaseYearArchiveView.get_dated_items(). This behavior is implemented in
+        BaseDateListView.get().
+        """
+        BookSigning.objects.create(event_date=datetime.datetime(2008, 4, 2, 12, 0))
+        with self.assertRaisesMessage(TypeError, 'context must be a dict rather than MagicMock.'):
+            self.client.get('/dates/booksignings/2008/')
+        args, kwargs = mock.call_args
+        # These are context values from get_dated_items().
+        self.assertEqual(kwargs['year'], datetime.date(2008, 1, 1))
+        self.assertIsNone(kwargs['previous_year'])
+        self.assertIsNone(kwargs['next_year'])
+
 
 @override_settings(ROOT_URLCONF='generic_views.urls')
 class MonthArchiveViewTests(TestDataMixin, TestCase):