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

Student ids are required

Error message

Student ids are required

What it means

PeerReview::StudentIdsRequiredError raised by validate_student_ids_required when student_ids is nil, an empty string, a whitespace-only string, or an empty array. At least one target student is needed to create peer reviews.

Solutions

1. Pass a non-empty array of student ids (e.g. [101, 102])
2. Fix the client to require at least one selected student before submit
3. Verify the param key name matches what the service expects

Example fix

// before
service.call(student_ids: params[:students] || []) # empty array
// after
return unless params[:students].present?
service.call(student_ids: params[:students].map(&:to_i))

raise ArgumentError, 'student_ids must be a non-empty array' if student_ids.nil? || (student_ids.respond_to?(:empty?) && student_ids.empty?) || student_ids.to_s.strip.empty?

begin
  service.call(student_ids:)
rescue PeerReview::StudentIdsRequiredError => e
  render json: { error: e.message }, status: :bad_request
end

When it happens

Trigger: Calling a peer review creation service with student_ids: nil, '', ' ', or []; passing params[:student_ids] when the request body omitted the field.

Common situations: Frontend submits with no students selected; array filtered down to empty before the call; JSON payload uses wrong key so student_ids stays nil.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Set id is required
• Set type is required
• Course does not exist
• Override does not exist
• Peer review due date cannot be after assignment until date

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/04add3117d8be8b0. Report an issue: GitHub.

Appendix: source

Thrown at app/services/peer_review/validations.rb:216

  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)
      supported_types = services.keys.join(", ")
      raise PeerReview::SetTypeNotSupportedError,
            I18n.t("Set type '%{set_type}' is not supported. Supported types are: %{supported_types}", set_type:, supported_types:)
    end
  end

  def validate_group_assignment_required(assignment)
    unless assignment.group_category_id
      raise PeerReview::GroupAssignmentRequiredError, I18n.t("Must be a group assignment to create group overrides")

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