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

Peer review sub assignments cannot have a not_graded…

Error message

Peer review sub assignments cannot have a not_graded grading type

What it means

PeerReview::Validations#validate_grading_type raises PeerReview::InvalidGradingTypeError when a grading type of "not_graded" is supplied for a peer review sub assignment. Sub assignments must carry a grade; the library explicitly rejects the not_graded enum value.

Solutions

1. Use a graded grading type such as "points", "percent", or "pass_fail" for the sub assignment.
2. Only propagate grading_type from the parent when the parent is actually graded; otherwise default to "points".
3. Validate grading_type in your client before submitting the request.

Example fix

// before
sub = PeerReview::SubAssignmentCreator.new(assignment: parent, grading_type: "not_graded")
// after
sub = PeerReview::SubAssignmentCreator.new(
  assignment: parent,
  grading_type: parent.grading_type == "not_graded" ? "points" : parent.grading_type
)

rejected = %w[not_graded]
raise ArgumentError, "invalid grading type" if rejected.include?(params[:grading_type])

begin
  service.call
rescue PeerReview::InvalidGradingTypeError => e
  render json: { error: e.message }, status: :unprocessable_entity
end

When it happens

Trigger: Creating/updating a peer review sub assignment with grading_type: "not_graded" in the API payload or service params.

Common situations: Copying parent assignment attributes (including not_graded) onto the sub assignment; API clients defaulting grading_type to not_graded; UI workflows that let users pick not_graded for review sub assignments.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Due date cannot be before available from date
• Invalid parent assignment
• Must be a group assignment to create group overrides
• Peer review sub assignment does not exist
• Peer review sub assignment exists

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/b9570dea0497ebe2. Report an issue: GitHub.

Appendix: source

Thrown at app/services/peer_review/validations.rb:40

    unless assignment.present? && assignment.is_a?(Assignment) && assignment.persisted?
      raise PeerReview::InvalidParentAssignmentError, I18n.t("Invalid parent assignment")
    end
  end

  def validate_peer_reviews_enabled(assignment)
    unless assignment.peer_reviews?
      raise PeerReview::PeerReviewsNotEnabledError, I18n.t("Peer reviews are not enabled for this assignment")
    end
  end

  def validate_feature_enabled(assignment)
    unless assignment.context.feature_enabled?(:peer_review_allocation_and_grading)
      raise PeerReview::FeatureDisabledError, I18n.t("Peer Review Allocation and Grading feature flag is disabled")
    end
  end

  def validate_grading_type(grading_type)
    raise PeerReview::InvalidGradingTypeError, I18n.t("Peer review sub assignments cannot have a not_graded grading type") if grading_type == "not_graded"
  end

  def validate_assignment_submission_types(assignment)
    if assignment.external_tool?
      raise PeerReview::InvalidAssignmentSubmissionTypesError, I18n.t("Peer reviews cannot be used with External Tool assignments")
    end

    if assignment.submission_types == "discussion_topic"
      raise PeerReview::InvalidAssignmentSubmissionTypesError, I18n.t("Peer reviews cannot be used with Discussion Topic assignments")
    end
  end

  def validate_peer_review_sub_assignment_exists(assignment)
    if assignment.peer_review_sub_assignment.blank?
      raise PeerReview::SubAssignmentNotExistError, I18n.t("Peer review sub assignment does not exist")
    end
  end

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