instructure/canvas-lms · error · Checkpoints::GroupAssignmentRequiredError

must be a group assignment in order to create group…

Error message

must be a group assignment in order to create group overrides

What it means

Checkpoints::GroupAssignmentRequiredError raised in GroupOverrideUpdaterService#call when the checkpoint has no effective group category AND the override is not a differentiation-tag override. Updates to group overrides require the checkpoint to remain a group assignment; the exception names 'create' because it shares the message with the creator.

Solutions

1. Restore a group category on the checkpoint/parent assignment before updating group overrides
2. Delete stale group overrides instead of updating them when the assignment became individual
3. Ensure differentiation-tag detection data (tags enabled for context, correct set_id) so the tag path is taken when intended
4. Rescue Checkpoints::GroupAssignmentRequiredError and return 422

Example fix

// before
Checkpoints::GroupOverrideUpdaterService.new(individual_checkpoint, { id: id, set_id: gid }).call
// after
return unless checkpoint.effective_group_category_id.present?
Checkpoints::GroupOverrideUpdaterService.new(checkpoint, { id: id, set_id: gid }).call

if checkpoint.effective_group_category_id.nil?
  return render json: { error: 'not a group assignment' }, status: :unprocessable_entity
end
Checkpoints::GroupOverrideUpdaterService.new(checkpoint, override).call

def updatable_group_override?(checkpoint, override)
  checkpoint.effective_group_category_id.present? || override[:set_id].present?
end

begin
  Checkpoints::GroupOverrideUpdaterService.new(checkpoint, override).call
rescue Checkpoints::GroupAssignmentRequiredError
  head :unprocessable_entity
end

When it happens

Trigger: Calling the updater with a group-set override payload for a checkpoint whose effective_group_category_id is nil and whose payload is not tagged as a differentiation-tag override (e.g. set_id points to a tag but differentiation tag path not detected).

Common situations: Assignment reverted from group to individual while old group overrides still exist and get updated; client updates an override whose set_type no longer matches the checkpoint's submission type.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• must be a group assignment in order to create group…
• Can't update submission scores unless it's completed
• set_id is required, but was not provided
• set_id is required, but was not provided
• set_id is required, but was not provided

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/714fb98e4401744a. Report an issue: GitHub.

Appendix: source

Thrown at app/services/checkpoints/group_override_updater_service.rb:33

# 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/>.

class Checkpoints::GroupOverrideUpdaterService < ApplicationService
  include Checkpoints::DateOverrider
  include Checkpoints::GroupOverrideCommon

  def initialize(checkpoint:, override:)
    super()
    @checkpoint = checkpoint
    @override = override
  end

  def call
    is_differentiation_tag_override = differentiation_tag_override?(@override, @checkpoint)
    if @checkpoint.effective_group_category_id.nil? && !is_differentiation_tag_override
      raise Checkpoints::GroupAssignmentRequiredError, "must be a group assignment in order to create group overrides"
    end

    override = @checkpoint.assignment_overrides.find_by(id: @override[:id], set_type: AssignmentOverride::SET_TYPE_GROUP)
    raise Checkpoints::OverrideNotFoundError unless override

    group_id = @override.fetch(:set_id, nil) || override.set_id

    raise Checkpoints::SetIdRequiredError, "set_id is required, but was not provided" if group_id.blank?

    group = is_differentiation_tag_override ? get_differentiation_tag_from_override(@override, @checkpoint) : get_group_from_override(@override, @checkpoint)

    current_group = override.set

    update_override(override:, group:)

    parent_override = @checkpoint.parent_assignment.active_assignment_overrides.find_by(set: current_group)
    raise Checkpoints::OverrideNotFoundError unless parent_override

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