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

Peer reviews are not enabled for this assignment

Error message

Peer reviews are not enabled for this assignment

What it means

PeerReview::Validations#validate_peer_reviews_enabled raises PeerReview::PeerReviewsNotEnabledError when the target assignment does not have `peer_reviews?` truthy. Peer review sub-assignments only make sense for assignments that have peer reviews turned on, so the library short-circuits when the parent assignment lacks the setting.

Solutions

1. Set `peer_reviews: true` on the assignment (assignment.update!(peer_reviews: true)) before running peer review services.
2. Enable 'Peer Reviews' in the assignment edit UI before creating sub assignments.
3. Guard the service call with `assignment.peer_reviews?` and skip or return early when disabled.

Example fix

// before
PeerReview::SubAssignmentCreator.new(assignment: assignment).call # peer_reviews not set
// after
assignment.update!(peer_reviews: true)
PeerReview::SubAssignmentCreator.new(assignment: assignment).call

return render json: { error: "peer reviews disabled" }, status: :unprocessable_entity unless assignment.peer_reviews?

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

When it happens

Trigger: Creating or manipulating a peer review sub assignment for an assignment whose `peer_reviews` attribute is false/unset; API calls to peer review endpoints without `peer_reviews: true` on the assignment.

Common situations: Assignment created through the API without the peer_reviews flag; admin disabled peer reviews after sub assignment creation; seeding scripts that forget `peer_reviews: true`.

Related errors

• Due date cannot be before available from date
• Invalid parent assignment
• Must be a group assignment to create group overrides
• Peer Review Allocation and Grading feature flag is disabled
• Peer review sub assignment does not exist

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/e985d9ea94b4c031. Report an issue: GitHub.

Appendix: source

Thrown at app/services/peer_review/validations.rb:29

#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.

module PeerReview::Validations
  def validate_parent_assignment(assignment)
    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

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