feat: show exception message from filters in the user interface (#35407)

common/djangoapps/student/models/course_enrollment.py

@@ -717,6 +717,8 @@ class CourseEnrollment(models.Model):
         Also emits relevant events for analytics purposes.
         """
         try:
+            # .. filter_implemented_name: CourseEnrollmentStarted
+            # .. filter_type: org.openedx.learning.course.enrollment.started.v1
             user, course_key, mode = CourseEnrollmentStarted.run_filter(
                 user=user, course_key=course_key, mode=mode,
             )

common/djangoapps/student/views/management.py

@@ -70,6 +70,7 @@ from common.djangoapps.student.message_types import AccountActivation, EmailChan
 from common.djangoapps.student.models import (  # lint-amnesty, pylint: disable=unused-import
     AccountRecovery,
     CourseEnrollment,
+    EnrollmentNotAllowed,
     PendingEmailChange,  # unimport:skip
     PendingSecondaryEmailChange,
     Registration,
@@ -422,6 +423,8 @@ def change_enrollment(request, check_access=True):
                 enroll_mode = CourseMode.auto_enroll_mode(course_id, available_modes)
                 if enroll_mode:
                     CourseEnrollment.enroll(user, course_id, check_access=check_access, mode=enroll_mode)
+            except EnrollmentNotAllowed as exc:
+                return HttpResponseBadRequest(str(exc))
             except Exception:  # pylint: disable=broad-except
                 return HttpResponseBadRequest(_("Could not enroll"))