Fixed #28959 -- Fixed 'No, take me back' button on admin's inline popup.

django/contrib/admin/static/admin/js/cancel.js

@@ -3,7 +3,11 @@
     $(function() {
         $('.cancel-link').on('click', function(e) {
             e.preventDefault();
-            window.history.back();
+            if (window.location.search.indexOf('&_popup=1') === -1) {
+                window.history.back();  // Go back if not a popup.
+            } else {
+                window.close(); // Otherwise, close the popup.
+            }
         });
     });
 })(django.jQuery);

tests/admin_views/tests.py

@@ -4394,6 +4394,20 @@ class SeleniumTests(AdminSeleniumTestCase):
         self.assertEqual(select.first_selected_option.text, '---------')
         self.assertEqual(select.first_selected_option.get_attribute('value'), '')
 
+    def test_inline_with_popup_cancel_delete(self):
+        """Clicking ""No, take me back" on a delete popup closes the window."""
+        parent = ParentWithUUIDPK.objects.create(title='test')
+        related_with_parent = RelatedWithUUIDPKModel.objects.create(parent=parent)
+        self.admin_login(username='super', password='secret', login_url=reverse('admin:index'))
+        change_url = reverse('admin:admin_views_relatedwithuuidpkmodel_change', args=(related_with_parent.id,))
+        self.selenium.get(self.live_server_url + change_url)
+        self.selenium.find_element_by_id('delete_id_parent').click()
+        self.wait_for_popup()
+        self.selenium.switch_to.window(self.selenium.window_handles[-1])
+        self.selenium.find_element_by_xpath('//a[text()="No, take me back"]').click()
+        self.selenium.switch_to.window(self.selenium.window_handles[0])
+        self.assertEqual(len(self.selenium.window_handles), 1)
+
     def test_list_editable_raw_id_fields(self):
         parent = ParentWithUUIDPK.objects.create(title='test')
         parent2 = ParentWithUUIDPK.objects.create(title='test2')