[1.6.x] Fixed #21510 -- Readded search reset link in changelist search bar

Thanks moritz.pfeiffer at alp-phone.ch for the report and
Tim Graham for the initial patch.
Backport of c7c647419c from master.

django/contrib/admin/views/main.py

@@ -223,7 +223,7 @@ class ChangeList(six.with_metaclass(RenameChangeListMethods)):
         # Perform a slight optimization:
         # full_result_count is equal to paginator.count if no filters
         # were applied
-        if self.get_filters_params():
+        if self.get_filters_params() or self.params.get(SEARCH_VAR):
             full_result_count = self.root_queryset.count()
         else:
             full_result_count = result_count

docs/releases/1.6.1.txt

@@ -47,3 +47,5 @@ Bug fixes
 * Fixed password hash upgrade when changing the iteration count (#21535).
 * Fixed a bug in the debug view when the urlconf only contains one element
   (#21530).
+* Re-added missing search result count and reset link in changelist admin view
+  (#21510).

tests/admin_views/tests.py

@@ -2242,6 +2242,15 @@ class AdminSearchTest(TestCase):
         self.assertContains(response, "\n1 pluggable search person\n")
         self.assertContains(response, "Amy")
 
+    def test_reset_link(self):
+        """
+        Test presence of reset link in search bar ("1 result (_x total_)").
+        """
+        response = self.client.get('/test_admin/admin/admin_views/person/?q=Gui')
+        self.assertContains(response,
+            """<span class="small quiet">1 result (<a href="?">3 total</a>)</span>""",
+            html=True)
+
 
 @override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
 class AdminInheritedInlinesTest(TestCase):
@@ -2665,17 +2674,17 @@ class AdminCustomQuerysetTest(TestCase):
             resp = self.client.get('/test_admin/admin/admin_views/person/')
             self.assertEqual(resp.context['selection_note'], '0 of 2 selected')
             self.assertEqual(resp.context['selection_note_all'], 'All 2 selected')
-        with self.assertNumQueries(4):
+        # here one more count(*) query will run, because filters were applied
+        with self.assertNumQueries(5):
             extra = {'q': 'not_in_name'}
             resp = self.client.get('/test_admin/admin/admin_views/person/', extra)
             self.assertEqual(resp.context['selection_note'], '0 of 0 selected')
             self.assertEqual(resp.context['selection_note_all'], 'All 0 selected')
-        with self.assertNumQueries(4):
+        with self.assertNumQueries(5):
             extra = {'q': 'person'}
             resp = self.client.get('/test_admin/admin/admin_views/person/', extra)
             self.assertEqual(resp.context['selection_note'], '0 of 2 selected')
             self.assertEqual(resp.context['selection_note_all'], 'All 2 selected')
-        # here one more count(*) query will run, because filters were applied
         with self.assertNumQueries(5):
             extra = {'gender__exact': '1'}
             resp = self.client.get('/test_admin/admin/admin_views/person/', extra)