instructure/canvas-lms · error · GraphQL::ExecutionError

Anonymous assignments cannot be hidden by section

Error message

Anonymous assignments cannot be hidden by section

What it means

Anonymous-student assignments (assignment.anonymize_students?) cannot have grades hidden or posted per-section, since filtering by section would link posted/hidden grade visibility to identifiable section membership. The mutation refuses the request up front.

Solutions

1. Call the whole-assignment hide (hideAssignmentGrades without section_ids) instead, if allowed — note anonymized assignments restrict posting entirely; check policy.
2. Disable 'Grade Anonymously' on the assignment (if no submissions/grades yet) when section-level grade management is required.
3. In UI, hide/disable the section picker whenever assignment.anonymizeStudents is true.
4. Distinguish the flags in client logic: anonymizeStudents vs anonymousGrading trigger different restrictions.

Example fix

// before
await HideBySection.mutate({ assignmentId, sectionIds });
// after
if (assignment.anonymizeStudents) {
  showError('Anonymous assignments cannot be managed by section');
} else {
  await HideBySection.mutate({ assignmentId, sectionIds });
}

if (assignment.anonymizeStudents && sectionIds?.length) {
  throw new ValidationError('Section-scoped hide is unavailable for anonymized assignments');
}

const allowsSectionScoping = (a) => Boolean(a && !a.anonymizeStudents && !a.anonymousGrading);

try { await hideBySection({ assignmentId, sectionIds }); }
catch (e) {
  if (String(e).includes('Anonymous assignments')) { showError('Use whole-assignment grade management for anonymized assignments'); return; }
  throw e;
}

When it happens

Trigger: Calling hideAssignmentGradesForSections on an assignment where 'Grade Anonymously' (anonymize_students) is on, with any section_ids.

Common situations: TA workflows in anonymous-grading assignments where per-section scoping is habitual; tooling that generically applies section filters to all assignments; confusion between anonymous_grading (provisional/moderated anonymity) and anonymize_students (grader anonymity) flags.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Anonymous assignments cannot be posted by section
• and cannot be used together
• A course with that id does not exist
• Anonymous assignments cannot be posted by graded only
• Anonymous assignments cannot be posted by section

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/2602086bb5795285. Report an issue: GitHub.

Appendix: source

Thrown at app/graphql/mutations/hide_assignment_grades_for_sections.rb:45

  field :assignment, Types::AssignmentType, null: true
  field :progress, Types::ProgressType, null: true
  field :sections, [Types::SectionType], null: true

  def resolve(input:)
    begin
      assignment = AbstractAssignment.find_assignment_or_peer_review(input[:assignment_id])
      course = assignment.context
      sections = course.course_sections.where(id: input[:section_ids])
    rescue ActiveRecord::RecordNotFound
      raise GraphQL::ExecutionError, "not found"
    end

    verify_authorized_action!(assignment, :grade)

    unless assignment.grades_published?
      raise GraphQL::ExecutionError, "Assignments under moderation cannot be hidden by section before grades are published"
    end
    raise GraphQL::ExecutionError, "Anonymous assignments cannot be hidden by section" if assignment.anonymize_students?

    if sections.empty? || sections.count != input[:section_ids].size
      raise GraphQL::ExecutionError, "Invalid section ids"
    end

    visible_enrollments = course.apply_enrollment_visibility(course.student_enrollments, current_user, sections)

    submissions_scope = input[:graded_only] ? assignment.submissions.graded : assignment.submissions
    submissions_scope = submissions_scope.joins(user: :enrollments).merge(visible_enrollments)

    progress = course.progresses.new(tag: "hide_assignment_grades_for_sections")

    if progress.save
      progress.process_job(
        assignment,
        :hide_submissions,
        { preserve_method_args: true, priority: Delayed::HIGH_PRIORITY },
        progress:,

View on GitHub (pinned to 1c9f0bb801)