instructure/canvas-lms · error · PeerReview::SectionNotFoundError

Section does not exist

Error message

Section does not exist

What it means

PeerReview::SectionNotFoundError raised by validate_section_exists when the given CourseSection is nil/not present. The section-based peer review service requires an existing section to resolve students.

Solutions

1. Fetch the section within the course scope and verify it exists before calling the service
2. Confirm the section id belongs to the same course and shard
3. Re-sync/re-list sections after SIS changes and use a current id

Example fix

// before
section = CourseSection.find_by(id: params[:section_id]) # possibly from another course
service.call(section: section)
// after
section = course.course_sections.find(params[:section_id])
service.call(section: section)

section = course.course_sections.find_by(id: section_id)
raise ArgumentError, 'section not found' unless section

begin
  service.call(section:)
rescue PeerReview::SectionNotFoundError
  head :not_found
end

When it happens

Trigger: Calling the section peer review service with a section id that resolves to nothing: deleted section, section from another course, or wrong id type causing lookup failure.

Common situations: Sections merged or deleted in SIS sync between fetch and call; hardcoded section id from a different course; using course_section_id where none exists for the account.

Understand the failure class

Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.

Related errors

• Course does not exist
• Override does not exist
• Parent assignment Section override not found for section
• Group does not exist
• Parent assignment ADHOC override not found for students

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/a0a9747e399d0b47. Report an issue: GitHub.

Appendix: source

Thrown at app/services/peer_review/validations.rb:207

      raise PeerReview::InvalidDatesError,
            is_override ? I18n.t("Peer review override until date cannot be after parent override until date") : I18n.t("Peer review until date cannot be after assignment until date")
    end
  end

  def validate_set_type_required(set_type)
    raise PeerReview::SetTypeRequiredError, I18n.t("Set type is required") unless set_type.present?
  end

  def validate_set_id_required(set_id)
    raise PeerReview::SetIdRequiredError, I18n.t("Set id is required") unless set_id.present?
  end

  def validate_override_exists(override)
    raise PeerReview::OverrideNotFoundError, I18n.t("Override does not exist") unless override.present?
  end

  def validate_section_exists(section)
    raise PeerReview::SectionNotFoundError, I18n.t("Section does not exist") unless section.present?
  end

  def validate_course_exists(course)
    raise PeerReview::CourseNotFoundError, I18n.t("Course does not exist") unless course.present?
  end

  def validate_student_ids_required(student_ids)
    if student_ids.nil? || student_ids == "" || student_ids.to_s.strip.empty? || (student_ids.is_a?(Array) && student_ids.empty?)
      raise PeerReview::StudentIdsRequiredError, I18n.t("Student ids are required")
    end
  end

  def validate_student_ids_in_course(student_ids)
    raise PeerReview::StudentIdsNotInCourseError, I18n.t("Student ids are not in course") if student_ids.blank?
  end

  def validate_set_type_supported(set_type, services)
    unless services.key?(set_type)

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