feat: add Waffle flag to control start date access for masquerading users

This introduces the `ENFORCE_MASQUERADE_START_DATES` flag.
When the flag is disabled (default), masquerading users bypass start dates.
When the flag is enabled, masquerading users see the same start date
restrictions as regular students.

lms/djangoapps/courseware/access_utils.py

@@ -23,7 +23,11 @@ from lms.djangoapps.courseware.access_response import (
     StartDateError,
 )
 from lms.djangoapps.courseware.masquerade import get_course_masquerade, is_masquerading_as_student
-from openedx.features.course_experience import COURSE_ENABLE_UNENROLLED_ACCESS_FLAG, COURSE_PRE_START_ACCESS_FLAG
+from openedx.features.course_experience import (
+    COURSE_ENABLE_UNENROLLED_ACCESS_FLAG,
+    COURSE_PRE_START_ACCESS_FLAG,
+    ENFORCE_MASQUERADE_START_DATES,
+)
 from xmodule.course_block import COURSE_VISIBILITY_PUBLIC  # lint-amnesty, pylint: disable=wrong-import-order
 
 DEBUG_ACCESS = False
@@ -137,7 +141,10 @@ def check_start_date(user, days_early_for_beta, start, course_key, display_error
     if start_dates_disabled and not masquerading_as_student:
         return ACCESS_GRANTED
     else:
-        if start is None or get_course_masquerade(user, course_key):
+        if start is None:
+            return ACCESS_GRANTED
+
+        if not ENFORCE_MASQUERADE_START_DATES.is_enabled(course_key) and get_course_masquerade(user, course_key):
             return ACCESS_GRANTED
 
         if now is None:

lms/djangoapps/courseware/tests/test_access.py

@@ -17,6 +17,7 @@ from django.test import TestCase
 from django.test.client import RequestFactory
 from django.test.utils import override_settings
 from django.urls import reverse
+from edx_toggles.toggles.testutils import override_waffle_flag
 from milestones.tests.utils import MilestonesTestCaseMixin
 from opaque_keys.edx.locator import CourseLocator
 
@@ -30,6 +31,7 @@ from openedx.core.djangoapps.content.course_overviews.models import CourseOvervi
 from openedx.core.djangoapps.content.course_overviews.tests.factories import CourseOverviewFactory
 from openedx.core.djangoapps.waffle_utils.testutils import WAFFLE_TABLES
 from openedx.features.content_type_gating.models import ContentTypeGatingConfig
+from openedx.features.course_experience import ENFORCE_MASQUERADE_START_DATES
 from common.djangoapps.student.models import CourseEnrollment
 from common.djangoapps.student.roles import CourseCcxCoachRole, CourseStaffRole
 from common.djangoapps.student.tests.factories import (
@@ -465,6 +467,50 @@ class AccessTestCase(LoginEnrollmentTestCase, ModuleStoreTestCase, MilestonesTes
 
         self.verify_access(mock_unit, expected_access, expected_error_type)
 
+    @ddt.data(
+        # Flag inactive (default)
+        (False, True, None),  # Masquerading, no start date
+        (False, True, YESTERDAY),  # Masquerading, past start date
+        (False, False, TOMORROW),  # Not masquerading, future start date
+        (False, True, TOMORROW),  # Masquerading, future start date
+        # Flag active
+        (True, True, None),  # Masquerading, no start date
+        (True, True, YESTERDAY),  # Masquerading, past start date
+        (True, False, TOMORROW),  # Not masquerading, future start date
+        (True, True, TOMORROW, False),  # Masquerading, future start date - no access
+    )
+    @ddt.unpack
+    @patch.dict("django.conf.settings.FEATURES", {"DISABLE_START_DATES": False})
+    def test_enforce_masquerade_start_dates_flag(self, flag_active, is_masquerading, start, expected_access=True):
+        """
+        Test that the ENFORCE_MASQUERADE_START_DATES flag controls whether masquerading bypasses start date
+        restrictions.
+
+        When the flag is disabled (default), masquerading users bypass start dates.
+        When the flag is enabled, masquerading users see the same start date restrictions as regular students.
+        """
+        mock_unit = Mock(
+            location=self.course.location,
+            user_partitions=[],
+            _class_tags={},
+            start=self.DATES[start],
+            visible_to_staff_only=False,
+            merged_group_access={},
+        )
+
+        if is_masquerading:
+            self.course_staff.masquerade_settings = {self.course.id: CourseMasquerade(self.course.id, role="student")}
+
+        with override_waffle_flag(ENFORCE_MASQUERADE_START_DATES, active=flag_active):
+            response = access._has_access_to_block(self.course_staff, "load", mock_unit, course_key=self.course.id)
+
+            if expected_access:
+                assert response == access.ACCESS_GRANTED
+            else:
+                assert isinstance(response, access_response.StartDateError)
+                assert response.to_json()["error_code"] is not None
+                assert str(self.DATES[start]) in response.developer_message
+
     def test__has_access_course_can_enroll(self):
         yesterday = datetime.datetime.now(pytz.utc) - datetime.timedelta(days=1)
         tomorrow = datetime.datetime.now(pytz.utc) + datetime.timedelta(days=1)

openedx/features/course_experience/__init__.py

@@ -83,6 +83,23 @@ RELATIVE_DATES_DISABLE_RESET_FLAG = CourseWaffleFlag(f'{WAFFLE_FLAG_NAMESPACE}.r
 # .. toggle_tickets: https://openedx.atlassian.net/browse/AA-36
 CALENDAR_SYNC_FLAG = CourseWaffleFlag(f'{WAFFLE_FLAG_NAMESPACE}.calendar_sync', __name__)  # lint-amnesty, pylint: disable=toggle-missing-annotation
 
+# .. toggle_name: course_experience.enforce_masquerade_start_dates
+# .. toggle_implementation: CourseWaffleFlag
+# .. toggle_default: False
+# .. toggle_description: When enabled, staff masquerading as students will see the same start date
+#   restrictions as actual students. This provides a more accurate preview experience by enforcing
+#   section and subsection start dates even when viewing the course as a masqueraded user.
+#   When disabled (default), masquerading continues to bypass start date restrictions as before.
+# .. toggle_use_cases: opt_in
+# .. toggle_creation_date: 2025-10-08
+# .. toggle_warning: Enabling this flag means staff members masquerading as students will not be able to access course
+#   content before its start date, which may impact course testing workflows.
+#   Also, when you masquerade as a student in a course that starts in the future, you will lock yourself out of the
+#   course in the current Django session. To revert this, you need to log out and log back in.
+ENFORCE_MASQUERADE_START_DATES = CourseWaffleFlag(
+    f'{WAFFLE_FLAG_NAMESPACE}.enforce_masquerade_start_dates', __name__
+)
+
 
 def course_home_page_title(_course):
     """