Fixed #26155 -- Skipped URL checks if no ROOTURL_CONF setting.

django/core/checks/urls.py

@@ -1,13 +1,17 @@
 from __future__ import unicode_literals
 
+from django.conf import settings
+
 from . import Tags, Warning, register
 
 
 @register(Tags.urls)
 def check_url_config(app_configs, **kwargs):
-    from django.urls import get_resolver
-    resolver = get_resolver()
-    return check_resolver(resolver)
+    if getattr(settings, 'ROOT_URLCONF', None):
+        from django.urls import get_resolver
+        resolver = get_resolver()
+        return check_resolver(resolver)
+    return []
 
 
 def check_resolver(resolver):

docs/releases/1.9.3.txt

@@ -9,4 +9,5 @@ Django 1.9.3 fixes several bugs in 1.9.2.
 Bugfixes
 ========
 
-* ...
+* Skipped URL checks (new in 1.9) if the ``ROOT_URLCONF`` setting isn't defined
+  (:ticket:`26155`).

tests/check_framework/test_urls.py

@@ -1,3 +1,4 @@
+from django.conf import settings
 from django.core.checks.urls import check_url_config
 from django.test import SimpleTestCase
 from django.test.utils import override_settings
@@ -35,3 +36,9 @@ class CheckUrlsTest(SimpleTestCase):
         self.assertEqual(warning.id, 'urls.W003')
         expected_msg = "Your URL pattern '^$' [name='name_with:colon'] has a name including a ':'."
         self.assertIn(expected_msg, warning.msg)
+
+    @override_settings(ROOT_URLCONF=None)
+    def test_no_root_urlconf_in_settings(self):
+        delattr(settings, 'ROOT_URLCONF')
+        result = check_url_config(None)
+        self.assertEqual(result, [])