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

Group does not exist

Error message

Group does not exist

What it means

PeerReview::GroupNotFoundError raised when validate_group_exists receives a nil/blank group. The service could not load the Group referenced for the override, so it refuses to proceed rather than creating an override bound to a nonexistent group.

Solutions

1. Check the group id exists in the target course: course.groups.exists?(group_id)
2. Re-fetch the group list for the assignment's group category — the group may have been deleted
3. Verify you are not mixing shard-local and global ids in a multi-shard environment
4. Pass the Group record itself when the service accepts it, so resolution happens in the right context

Example fix

// before
PeerReview::CreateGroupOverride.call(assignment:, group_id: params[:group_id])
// after
group = assignment.group_category.groups.find_by(id: params[:group_id])
raise ArgumentError, 'group not in assignment group set' unless group
PeerReview::CreateGroupOverride.call(assignment:, group_id: group.id)

group = Group.active.find_by(id: group_id)
raise ArgumentError, 'group not found' unless group&.context == course

null

begin
  PeerReview::CreateGroupOverride.call(assignment:, group_id:)
rescue PeerReview::GroupNotFoundError
  render json: { error: 'Group does not exist' }, status: :not_found
end

When it happens

Trigger: Calling a PeerReview group override service with a group_id that does not exist, was deleted, or belongs to a different course/shard — the resulting Group lookup returns nil.

Common situations: Stale group id cached in the client after the group was deleted; wrong course context; cross-shard id confusion in a Switchman-sharded Canvas; typo in the id.

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

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

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/93ce6be04a736f56. Report an issue: GitHub.

Appendix: source

Thrown at app/services/peer_review/validations.rb:239

    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")
    end
  end

  def validate_group_exists(group)
    raise PeerReview::GroupNotFoundError, I18n.t("Group does not exist") unless group.present?
  end

  def validate_adhoc_parent_override_exists(parent_override, student_ids)
    unless parent_override.present?
      raise PeerReview::ParentOverrideNotFoundError,
            I18n.t("Parent assignment ADHOC override not found for students %{student_ids}", student_ids: student_ids.join(", "))
    end
  end

  def validate_course_parent_override_exists(parent_override, course_id)
    unless parent_override.present?
      raise PeerReview::ParentOverrideNotFoundError,
            I18n.t("Parent assignment Course override not found for course %{course_id}", course_id:)
    end
  end

  def validate_group_parent_override_exists(parent_override, group_id)
    unless parent_override.present?

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