ARCHBOM-1305: remove deprecated flag_undefined_default (#24426)

This is the final step in removing the deprecated
flag_undefined_default as explained by the following ADR:
https://github.com/edx/edx-platform/blob/master/openedx/core/djangoapps/waffle_utils/docs/decisions/0001-refactor-waffle-flag-default.rst

Notes:

* All uses of flag_undefined_default=False were always
  supposed to have been no-ops.
* All uses of flag_undefined_default=True that are removed
  in this PR have been replaced by migrations in past PRs.
* The temporary metric temp_flag_default_used id no longer
  reporting any data.

ARCHBOM-1305

cms/djangoapps/contentstore/config/waffle.py

@@ -30,18 +30,15 @@ def waffle_flags():
 ENABLE_PROCTORING_PROVIDER_OVERRIDES = CourseWaffleFlag(
     waffle_namespace=waffle_flags(),
     flag_name=u'enable_proctoring_provider_overrides',
-    flag_undefined_default=False
 )
 
 # TODO: After removing this flag, add a migration to remove waffle flag in a follow-up deployment.
 ENABLE_CHECKLISTS_QUALITY = CourseWaffleFlag(
     waffle_namespace=waffle_flags(),
     flag_name=u'enable_checklists_quality',
-    flag_undefined_default=True
 )
 
 SHOW_REVIEW_RULES_FLAG = CourseWaffleFlag(
     waffle_namespace=waffle_flags(),
     flag_name=u'show_review_rules',
-    flag_undefined_default=False
 )

cms/djangoapps/contentstore/views/videos.py

@@ -81,7 +81,6 @@ WAFFLE_STUDIO_FLAG_NAMESPACE = WaffleFlagNamespace(name=u'studio')
 ENABLE_VIDEO_UPLOAD_PAGINATION = CourseWaffleFlag(
     waffle_namespace=WAFFLE_STUDIO_FLAG_NAMESPACE,
     flag_name=u'enable_video_upload_pagination',
-    flag_undefined_default=False
 )
 # Default expiration, in seconds, of one-time URLs used for uploading videos.
 KEY_EXPIRATION_IN_SECONDS = 86400

lms/djangoapps/course_api/blocks/toggles.py

@@ -23,5 +23,4 @@ COURSE_BLOCKS_API_NAMESPACE = WaffleFlagNamespace(name=u'course_blocks_api')
 HIDE_ACCESS_DENIALS_FLAG = WaffleFlag(
     waffle_namespace=COURSE_BLOCKS_API_NAMESPACE,
     flag_name=u'hide_access_denials',
-    flag_undefined_default=False
 )

lms/djangoapps/experiments/flags.py

@@ -61,7 +61,7 @@ class ExperimentWaffleFlag(CourseWaffleFlag):
         self.num_buckets = num_buckets
         self.experiment_id = experiment_id
         self.bucket_flags = [
-            CourseWaffleFlag(waffle_namespace, '{}.{}'.format(flag_name, bucket), flag_undefined_default=False)
+            CourseWaffleFlag(waffle_namespace, '{}.{}'.format(flag_name, bucket))
             for bucket in range(num_buckets)
         ]
 

lms/djangoapps/experiments/views_custom.py

@@ -45,7 +45,6 @@ from track import segment
 MOBILE_UPSELL_FLAG = WaffleFlag(
     waffle_namespace=WaffleFlagNamespace(name=u'experiments'),
     flag_name=u'mobile_upsell_rev934',
-    flag_undefined_default=False
 )
 MOBILE_UPSELL_EXPERIMENT = 'mobile_upsell_experiment'
 

lms/djangoapps/grades/config/waffle.py

@@ -38,25 +38,21 @@ def waffle_flags():
         REJECTED_EXAM_OVERRIDES_GRADE: CourseWaffleFlag(
             namespace,
             REJECTED_EXAM_OVERRIDES_GRADE,
-            flag_undefined_default=True,
         ),
         # TODO: After removing this flag, add a migration to remove waffle flag in a follow-up deployment.
         ENFORCE_FREEZE_GRADE_AFTER_COURSE_END: CourseWaffleFlag(
             namespace,
             ENFORCE_FREEZE_GRADE_AFTER_COURSE_END,
-            flag_undefined_default=True,
         ),
         # Have this course override flag so we can selectively turn off the gradebook for courses.
         # TODO: After removing this flag, add a migration to remove waffle flag in a follow-up deployment.
         WRITABLE_GRADEBOOK: CourseWaffleFlag(
             namespace,
             WRITABLE_GRADEBOOK,
-            flag_undefined_default=True,
         ),
         BULK_MANAGEMENT: CourseWaffleFlag(
             namespace,
             BULK_MANAGEMENT,
-            flag_undefined_default=False,
         ),
     }
 

lms/djangoapps/grades/tests/test_tasks.py

@@ -164,10 +164,10 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
             self.assertEqual(mock_block_structure_create.call_count, 1)
 
     @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 37, True),
-        (ModuleStoreEnum.Type.mongo, 1, 37, False),
-        (ModuleStoreEnum.Type.split, 3, 37, True),
-        (ModuleStoreEnum.Type.split, 3, 37, False),
+        (ModuleStoreEnum.Type.mongo, 1, 36, True),
+        (ModuleStoreEnum.Type.mongo, 1, 36, False),
+        (ModuleStoreEnum.Type.split, 3, 36, True),
+        (ModuleStoreEnum.Type.split, 3, 36, False),
     )
     @ddt.unpack
     def test_query_counts(self, default_store, num_mongo_calls, num_sql_calls, create_multiple_subsections):
@@ -179,8 +179,8 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
                     self._apply_recalculate_subsection_grade()
 
     @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 37),
-        (ModuleStoreEnum.Type.split, 3, 37),
+        (ModuleStoreEnum.Type.mongo, 1, 36),
+        (ModuleStoreEnum.Type.split, 3, 36),
     )
     @ddt.unpack
     def test_query_counts_dont_change_with_more_content(self, default_store, num_mongo_calls, num_sql_calls):
@@ -225,8 +225,8 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
         )
 
     @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 20),
-        (ModuleStoreEnum.Type.split, 3, 20),
+        (ModuleStoreEnum.Type.mongo, 1, 19),
+        (ModuleStoreEnum.Type.split, 3, 19),
     )
     @ddt.unpack
     def test_persistent_grades_not_enabled_on_course(self, default_store, num_mongo_queries, num_sql_queries):
@@ -240,8 +240,8 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
             self.assertEqual(len(PersistentSubsectionGrade.bulk_read_grades(self.user.id, self.course.id)), 0)
 
     @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 38),
-        (ModuleStoreEnum.Type.split, 3, 38),
+        (ModuleStoreEnum.Type.mongo, 1, 37),
+        (ModuleStoreEnum.Type.split, 3, 37),
     )
     @ddt.unpack
     def test_persistent_grades_enabled_on_course(self, default_store, num_mongo_queries, num_sql_queries):

lms/djangoapps/instructor/toggles.py

@@ -22,7 +22,6 @@ WAFFLE_FLAG_NAMESPACE = WaffleFlagNamespace(name='instructor')
 OPTIMISED_IS_SMALL_COURSE = WaffleFlag(
     waffle_namespace=WAFFLE_FLAG_NAMESPACE,
     flag_name='optimised_is_small_course',
-    flag_undefined_default=False
 )
 
 

lms/djangoapps/instructor_task/config/waffle.py

@@ -25,12 +25,10 @@ def waffle_flags():
         GENERATE_PROBLEM_GRADE_REPORT_VERIFIED_ONLY: CourseWaffleFlag(
             waffle_namespace=INSTRUCTOR_TASK_WAFFLE_FLAG_NAMESPACE,
             flag_name=GENERATE_PROBLEM_GRADE_REPORT_VERIFIED_ONLY,
-            flag_undefined_default=False,
         ),
         GENERATE_COURSE_GRADE_REPORT_VERIFIED_ONLY: CourseWaffleFlag(
             waffle_namespace=INSTRUCTOR_TASK_WAFFLE_FLAG_NAMESPACE,
             flag_name=GENERATE_COURSE_GRADE_REPORT_VERIFIED_ONLY,
-            flag_undefined_default=False,
         ),
     }
 

lms/djangoapps/verify_student/toggles.py

@@ -22,7 +22,6 @@ WAFFLE_FLAG_NAMESPACE = WaffleFlagNamespace(name='verify_student')
 USE_NEW_EMAIL_TEMPLATES = WaffleFlag(
     waffle_namespace=WAFFLE_FLAG_NAMESPACE,
     flag_name='use_new_email_templates',
-    flag_undefined_default=False
 )
 
 

openedx/core/djangoapps/models/config/waffle.py

@@ -26,7 +26,6 @@ def waffle_flags():
         COURSE_DETAIL_UPDATE_CERTIFICATE_DATE: CourseWaffleFlag(
             waffle_namespace=COURSE_DETAIL_WAFFLE_NAMESPACE,
             flag_name=COURSE_DETAIL_UPDATE_CERTIFICATE_DATE,
-            flag_undefined_default=False,
         )
     }
 

openedx/core/djangoapps/schedules/config.py

@@ -14,13 +14,11 @@ WAFFLE_SWITCH_NAMESPACE = WaffleSwitchNamespace(name=u'schedules')
 CREATE_SCHEDULE_WAFFLE_FLAG = CourseWaffleFlag(
     waffle_namespace=WAFFLE_FLAG_NAMESPACE,
     flag_name=u'create_schedules_for_course',
-    flag_undefined_default=False
 )
 
 COURSE_UPDATE_WAFFLE_FLAG = CourseWaffleFlag(
     waffle_namespace=WAFFLE_FLAG_NAMESPACE,
     flag_name=u'send_updates_for_course',
-    flag_undefined_default=False
 )
 
 DEBUG_MESSAGE_WAFFLE_FLAG = WaffleFlag(WAFFLE_FLAG_NAMESPACE, u'enable_debugging')

openedx/core/djangoapps/user_authn/views/register.py

@@ -109,7 +109,6 @@ REGISTER_USER = Signal(providing_args=["user", "registration"])
 REGISTRATION_FAILURE_LOGGING_FLAG = WaffleFlag(
     waffle_namespace=WaffleFlagNamespace(name=u'registration'),
     flag_name=u'enable_failure_logging',
-    flag_undefined_default=False
 )
 
 

openedx/core/djangoapps/video_pipeline/config/waffle.py

@@ -27,11 +27,9 @@ def waffle_flags():
         ENABLE_DEVSTACK_VIDEO_UPLOADS: WaffleFlag(
             waffle_namespace=namespace,
             flag_name=ENABLE_DEVSTACK_VIDEO_UPLOADS,
-            flag_undefined_default=False
         ),
         ENABLE_VEM_PIPELINE: CourseWaffleFlag(
             waffle_namespace=namespace,
             flag_name=ENABLE_VEM_PIPELINE,
-            flag_undefined_default=False
         )
     }

openedx/core/djangoapps/waffle_utils/__init__.py

@@ -226,7 +226,7 @@ class WaffleFlagNamespace(six.with_metaclass(ABCMeta, WaffleNamespace)):
         """
         return self._get_request_cache().setdefault('flags', {})
 
-    def is_flag_active(self, flag_name, check_before_waffle_callback=None, flag_undefined_default=None):
+    def is_flag_active(self, flag_name, check_before_waffle_callback=None):
         """
         Returns and caches whether the provided flag is active.
 
@@ -239,6 +239,10 @@ class WaffleFlagNamespace(six.with_metaclass(ABCMeta, WaffleNamespace)):
         Important: Caching for the check_before_waffle_callback must be handled
             by the callback itself.
 
+        Note: A waffle flag's default is False if not defined. If you think you
+            need the default to be True, see the module docstring for
+            alternatives.
+
         Arguments:
             flag_name (String): The name of the flag to check.
             check_before_waffle_callback (function): (Optional) A function that
@@ -246,63 +250,56 @@ class WaffleFlagNamespace(six.with_metaclass(ABCMeta, WaffleNamespace)):
                 check_before_waffle_callback(namespaced_flag_name) returns True
                 or False, it is returned. If it returns None, then waffle is
                 used.
-            DEPRECATED flag_undefined_default (Boolean): A default value to be
-                returned if the waffle flag is to be checked, but doesn't exist.
-                See module docstring for alternative.
-        """
-        # Import is placed here to avoid model import at project startup.
-        from waffle.models import Flag
-
-        if flag_undefined_default:
-            warnings.warn(
-                # NOTE: This will be removed once ARCHBOM-132, currently in-progress, is complete.
-                'flag_undefined_default has been deprecated. For existing uses this is already actively being fixed.',
-                DeprecationWarning
-            )
 
+        """
         # validate arguments
         namespaced_flag_name = self._namespaced_name(flag_name)
-        value = None
+
         if check_before_waffle_callback:
             value = check_before_waffle_callback(namespaced_flag_name)
-
-        if value is None:
-            # Do not get cached value for the callback, because the key might be different.
-            # The callback needs to handle its own caching if it wants it.
-            value = self._cached_flags.get(namespaced_flag_name)
-            if value is None:
-                is_flag_active_for_everyone = False
-                if flag_undefined_default is not None:
-                    # determine if the flag is undefined in waffle
-                    try:
-                        waffle_flag = Flag.objects.get(name=namespaced_flag_name)
-                        is_flag_active_for_everyone = (waffle_flag.everyone is True)
-                    except Flag.DoesNotExist:
-                        if flag_undefined_default:
-                            # This metric will go away once this has been fully retired with ARCHBOM-132.
-                            # Also, even though the value will only track the last flag, that should be enough.
-                            set_custom_metric('temp_flag_default_used', namespaced_flag_name)
-                        value = flag_undefined_default
-
-                if value is None:
-                    request = crum.get_current_request()
-                    if request:
-                        value = flag_is_active(request, namespaced_flag_name)
-                    else:
-                        log.warning(u"%sFlag '%s' accessed without a request", self.log_prefix, namespaced_flag_name)
-                        # Return the Flag's Everyone value if not in a request context.
-                        # Note: this skips the cache as the value might be different
-                        # in a normal request context. This case seems to occur when
-                        # a page redirects to a 404, or in Celery workers.
-                        self._set_waffle_flag_metric(namespaced_flag_name, is_flag_active_for_everyone)
-                        set_custom_metric('warn_flag_no_request_return_value', is_flag_active_for_everyone)
-                        return is_flag_active_for_everyone
-
-                self._cached_flags[namespaced_flag_name] = value
+            if value is not None:
+                # Do not cache value for the callback, because the key might be different.
+                # The callback needs to handle its own caching if it wants it.
+                self._set_waffle_flag_metric(namespaced_flag_name, value)
+                return value
+
+        value = self._cached_flags.get(namespaced_flag_name)
+        if value is not None:
+            self._set_waffle_flag_metric(namespaced_flag_name, value)
+            return value
+
+        request = crum.get_current_request()
+        if not request:
+            log.warning(u"%sFlag '%s' accessed without a request", self.log_prefix, namespaced_flag_name)
+            # Return the Flag's Everyone value if not in a request context.
+            # Note: this skips the cache as the value might be different
+            # in a normal request context. This case seems to occur when
+            # a page redirects to a 404, or for celery workers.
+            value = self._is_flag_active_for_everyone(namespaced_flag_name)
+            self._set_waffle_flag_metric(namespaced_flag_name, value)
+            set_custom_metric('warn_flag_no_request_return_value', value)
+            return value
+
+        value = flag_is_active(request, namespaced_flag_name)
+        self._cached_flags[namespaced_flag_name] = value
 
         self._set_waffle_flag_metric(namespaced_flag_name, value)
         return value
 
+    def _is_flag_active_for_everyone(self, namespaced_flag_name):
+        """
+        Returns True if the waffle flag is configured as active for Everyone,
+        False otherwise.
+        """
+        # Import is placed here to avoid model import at project startup.
+        from waffle.models import Flag
+
+        try:
+            waffle_flag = Flag.objects.get(name=namespaced_flag_name)
+            return (waffle_flag.everyone is True)
+        except Flag.DoesNotExist:
+            return False
+
     def _set_waffle_flag_metric(self, name, value):
         """
         For any flag name in _WAFFLE_FLAG_CUSTOM_METRIC_SET, add name/value
@@ -378,16 +375,14 @@ class WaffleFlag(object):
     Represents a single waffle flag, using a cached waffle namespace.
     """
 
-    def __init__(self, waffle_namespace, flag_name, flag_undefined_default=None):
+    def __init__(self, waffle_namespace, flag_name):
         """
         Initializes the waffle flag instance.
 
         Arguments:
             waffle_namespace (WaffleFlagNamespace | String): Namespace for this flag.
             flag_name (String): The name of the flag (without namespacing).
-            DEPRECATED flag_undefined_default (Boolean): A default value to be returned
-                if the waffle flag is to be checked, but doesn't exist. See module
-                docstring for alternative.
+
         """
         if isinstance(waffle_namespace, six.string_types):
             waffle_namespace = WaffleFlagNamespace(name=waffle_namespace)
@@ -395,7 +390,6 @@ class WaffleFlag(object):
         self.waffle_namespace = waffle_namespace
         self.waffle_namespace = waffle_namespace
         self.flag_name = flag_name
-        self.flag_undefined_default = flag_undefined_default
 
     @property
     def namespaced_flag_name(self):
@@ -408,10 +402,7 @@ class WaffleFlag(object):
         """
         Returns whether or not the flag is enabled.
         """
-        return self.waffle_namespace.is_flag_active(
-            self.flag_name,
-            flag_undefined_default=self.flag_undefined_default
-        )
+        return self.waffle_namespace.is_flag_active(self.flag_name)
 
     @contextmanager
     def override(self, active=True):
@@ -476,7 +467,6 @@ class CourseWaffleFlag(WaffleFlag):
         return self.waffle_namespace.is_flag_active(
             self.flag_name,
             check_before_waffle_callback=self._get_course_override_callback(course_key),
-            flag_undefined_default=self.flag_undefined_default
         )
 
     def is_enabled_without_course_context(self):

openedx/core/djangoapps/waffle_utils/docs/decisions/0001-refactor-waffle-flag-default.rst

@@ -30,6 +30,8 @@ Consequences
 
 * We will need to implement one of the alternate solutions for each flag currently using ``flag_undefined_default=True``, and then finally remove the deprecated ``flag_undefined_default`` argument.
 
+UPDATE: This work has been completed and ``flag_undefined_default`` has been removed.
+
 Rejected Alternatives
 =====================
 

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

@@ -94,19 +94,13 @@ class TestCourseWaffleFlag(TestCase):
 
     @override_settings(WAFFLE_FLAG_CUSTOM_METRICS=[NAMESPACED_FLAG_NAME])
     @patch('openedx.core.djangoapps.waffle_utils.set_custom_metric')
-    @ddt.data(
-        {'flag_undefined_default': None, 'result': False},
-        {'flag_undefined_default': False, 'result': False},
-        {'flag_undefined_default': True, 'result': True},
-    )
-    def test_undefined_waffle_flag(self, data, mock_set_custom_metric):
+    def test_undefined_waffle_flag(self, mock_set_custom_metric):
         """
-        Test flag with various defaults provided for undefined waffle flags.
+        Test flag with undefined waffle flag.
         """
         test_course_flag = CourseWaffleFlag(
             self.TEST_NAMESPACE,
             self.FLAG_NAME,
-            flag_undefined_default=data['flag_undefined_default']
         )
 
         with patch(
@@ -119,8 +113,8 @@ class TestCourseWaffleFlag(TestCase):
                 return_value=WaffleFlagCourseOverrideModel.ALL_CHOICES.unset
             ):
                 # check twice to test that the result is properly cached
-                self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), data['result'])
-                self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), data['result'])
+                self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), False)
+                self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), False)
                 # result is cached, so override check should happen once
                 WaffleFlagCourseOverrideModel.override_value.assert_called_once_with(
                     self.NAMESPACED_FLAG_NAME,
@@ -129,26 +123,31 @@ class TestCourseWaffleFlag(TestCase):
 
         self._assert_waffle_flag_metric(
             mock_set_custom_metric,
-            expected_flag_value=str(data['result']),
-            flag_undefined_default=data['flag_undefined_default'],
+            expected_flag_value=str(False),
         )
 
-    @ddt.data(
-        {'flag_undefined_default': None, 'result': False},
-        {'flag_undefined_default': False, 'result': False},
-        {'flag_undefined_default': True, 'result': True},
-    )
-    def test_without_request(self, data):
+    def test_without_request_and_undefined_waffle(self):
+        """
+        Test the flag behavior when outside a request context and waffle data undefined.
+        """
+        crum.set_current_request(None)
+        test_course_flag = CourseWaffleFlag(
+            self.TEST_NAMESPACE,
+            self.FLAG_NAME,
+        )
+        self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), False)
+
+    def test_without_request_and_everyone_active_waffle(self):
         """
-        Test the flag behavior when outside a request context.
+        Test the flag behavior when outside a request context and waffle active for everyone.
         """
         crum.set_current_request(None)
         test_course_flag = CourseWaffleFlag(
             self.TEST_NAMESPACE,
             self.FLAG_NAME,
-            flag_undefined_default=data['flag_undefined_default']
         )
-        self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), data['result'])
+        with override_flag(self.NAMESPACED_FLAG_NAME, active=True):
+            self.assertEqual(test_course_flag.is_enabled(self.TEST_COURSE_KEY), True)
 
     @ddt.data(
         {'expected_count': 0, 'waffle_flag_metric_setting': None},
@@ -169,13 +168,12 @@ class TestCourseWaffleFlag(TestCase):
 
         self.assertEqual(mock_set_custom_metric.call_count, data['expected_count'])
 
-    def _assert_waffle_flag_metric(self, mock_set_custom_metric, expected_flag_value=None, flag_undefined_default=None):
+    def _assert_waffle_flag_metric(self, mock_set_custom_metric, expected_flag_value=None):
         if expected_flag_value:
             expected_flag_name = 'flag_{}'.format(self.NAMESPACED_FLAG_NAME)
             expected_calls = [call(expected_flag_name, expected_flag_value)]
             mock_set_custom_metric.assert_has_calls(expected_calls)
-            expected_call_count = 2 if flag_undefined_default else 1
-            self.assertEqual(mock_set_custom_metric.call_count, expected_call_count)
+            self.assertEqual(mock_set_custom_metric.call_count, 1)
         else:
             self.assertEqual(mock_set_custom_metric.call_count, 0)
 

openedx/features/course_experience/__init__.py

@@ -22,7 +22,7 @@ class DefaultTrueWaffleFlagNamespace(WaffleFlagNamespace):
         and refactor/fix any tests that shouldn't be removed.
 
     """
-    def is_flag_active(self, flag_name, check_before_waffle_callback=None, flag_undefined_default=None):
+    def is_flag_active(self, flag_name, check_before_waffle_callback=None):
         """
         Overrides is_flag_active, and returns and caches whether the provided flag is active.
 

openedx/features/discounts/applicability.py

@@ -40,7 +40,6 @@ from track import segment
 DISCOUNT_APPLICABILITY_FLAG = WaffleFlag(
     waffle_namespace=WaffleFlagNamespace(name=u'discounts'),
     flag_name=u'enable_discounting',
-    flag_undefined_default=False
 )
 
 DISCOUNT_APPLICABILITY_HOLDBACK = 'first_purchase_discount_holdback'