Fix error in toggle state endpoint in the absence of module_name

When module_name is None, the call to edx-django-utils'
get_code_owner_from_module crashes. So we avoid making that call when
the module_name is None, which sometimes happens (for good reasons or
not, but it's valid behaviour).

openedx/core/djangoapps/waffle_utils/tests/test_views.py

@@ -2,14 +2,16 @@
 Tests for waffle utils views.
 """
 from django.test import TestCase
+from edx_django_utils.monitoring.code_owner import utils as code_owner_utils
+from mock import patch
 from rest_framework.test import APIRequestFactory
 from waffle.testutils import override_switch
 
 from student.tests.factories import UserFactory
 
 from .. import WaffleFlag, WaffleFlagNamespace, WaffleSwitch, WaffleSwitchNamespace
-from ..views import ToggleStateView
 from ..testutils import override_waffle_flag
+from ..views import ToggleStateView
 
 TEST_WAFFLE_FLAG_NAMESPACE = WaffleFlagNamespace('test')
 TEST_WAFFLE_FLAG = WaffleFlag(TEST_WAFFLE_FLAG_NAMESPACE, 'flag', __name__)
@@ -45,6 +47,17 @@ class ToggleStateViewTests(TestCase):
         # This is no longer the first switch
         #self.assertEqual(response.data['waffle_switches'][0]['name'], 'test.switch')
 
+    def test_code_owners_without_module_information(self):
+        # Create a waffle flag without any associated module_name
+        waffle_flag = WaffleFlag(TEST_WAFFLE_FLAG_NAMESPACE, "flag2", module_name=None)
+        with patch.object(code_owner_utils, "get_code_owner_mappings", return_value={}):
+            response = self._get_toggle_state_response(is_staff=True)
+
+        result = [
+            flag for flag in response.data["waffle_flags"] if flag["name"] == waffle_flag.name
+        ][0]
+        self.assertNotIn("code_owner", result)
+
     def _get_toggle_state_response(self, is_staff=True):
         request = APIRequestFactory().get('/api/toggles/state/')
         user = UserFactory()

openedx/core/djangoapps/waffle_utils/views.py

@@ -2,13 +2,13 @@
 Views that we will use to view toggle state in edx-platform.
 """
 from collections import OrderedDict
-from django.conf import settings
 
-from edx_django_utils.monitoring.code_owner.utils import get_code_owner_from_module, is_code_owner_mappings_configured
+from django.conf import settings
+from edx_django_utils.monitoring import get_code_owner_from_module
 from edx_rest_framework_extensions.auth.jwt.authentication import JwtAuthentication
 from edx_rest_framework_extensions.permissions import IsStaff
-from rest_framework.authentication import SessionAuthentication
 from rest_framework import permissions, views
+from rest_framework.authentication import SessionAuthentication
 from rest_framework.response import Response
 from waffle.models import Flag, Switch
 
@@ -107,7 +107,7 @@ class ToggleStateView(views.APIView):
         """
         toggle['class'] = toggle_instance.__class__.__name__
         toggle['module'] = toggle_instance.module_name
-        if is_code_owner_mappings_configured():
+        if toggle_instance.module_name:
             code_owner = get_code_owner_from_module(toggle_instance.module_name)
             if code_owner:
                 toggle['code_owner'] = code_owner