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 GroupOverrideCreatorService#handle_group_override when the checkpoint's effective_group_category_id is nil. Group overrides only make sense on group assignments; the service refuses to create one for an individual (non-group) checkpoint. effective_group_category_id resolves the checkpoint's inherited or own group category.

Solutions

1. Set a group_category_id on the checkpoint/parent assignment before creating group overrides
2. Only submit group overrides when the assignment type is group_grade_by_group / has a group category
3. Verify checkpoint.effective_group_category_id is present in the client before sending the request
4. Rescue Checkpoints::GroupAssignmentRequiredError and return 422 explaining the assignment must be a group assignment

Example fix

// before
service = Checkpoints::GroupOverrideCreatorService.new(individual_checkpoint, { set_id: group.id })
service.call # raises
// after
checkpoint.parent_assignment.update!(group_category_id: gc.id)
service = Checkpoints::GroupOverrideCreatorService.new(checkpoint, { set_id: group.id })

raise Checkpoints::GroupAssignmentRequiredError if checkpoint.effective_group_category_id.nil?
Checkpoints::GroupOverrideCreatorService.new(checkpoint, override).call

def group_checkpoint?(checkpoint)
  checkpoint.effective_group_category_id.present?
end

begin
  Checkpoints::GroupOverrideCreatorService.new(checkpoint, override).call
rescue Checkpoints::GroupAssignmentRequiredError
  render json: { error: 'checkpoint must be a group assignment' }, status: :unprocessable_entity
end

When it happens

Trigger: Calling Checkpoints::GroupOverrideCreatorService for a checkpoint that is not a group assignment (no group category set on the checkpoint or its parent assignment).

Common situations: Frontend sends group overrides for a checkpoint whose parent was switched back to individual submission; a group category was deleted leaving the checkpoint individual; ordering bug where overrides are created before group_category_id is assigned.

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/4eafe05f9e87e60d. Report an issue: GitHub.

Appendix: source

Thrown at app/services/checkpoints/group_override_creator_service.rb:42

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

  def call
    if differentiation_tag_override?(@override, @checkpoint)
      handle_differentiation_tag_override
    else
      handle_group_override
    end
  end

  private

  def handle_group_override
    if @checkpoint.effective_group_category_id.nil?
      raise Checkpoints::GroupAssignmentRequiredError, "must be a group assignment in order to create group overrides"
    end

    group = get_group_from_override(@override, @checkpoint)
    parent_override = parent_override(group)
    create_override(assignment: @checkpoint, group:, parent_override:)
  end

  def handle_differentiation_tag_override
    tag = get_differentiation_tag_from_override(@override, @checkpoint)
    parent_override = parent_override(tag)
    create_override(assignment: @checkpoint, group: tag, parent_override:)
  end

  def create_override(assignment:, group:, shell_override: false, parent_override: nil)
    override = assignment.assignment_overrides.build(set: group, dont_touch_assignment: true, parent_override:)
    apply_overridden_dates(override, @override, shell_override:)
    override.save!
    override

View on GitHub (pinned to 1c9f0bb801)