instructure/canvas-lms · error

unknown item type

Error message

unknown item type

What it means

ItemVisibilityHelper#visible_item_ids_for_users only accepts item types in ITEM_TYPES (:assignment, :discussion, :page, :quiz). Any other symbol raises 'unknown item type' before computing per-user visibility.

Solutions

  1. Use one of :assignment, :discussion, :page, :quiz.
  2. Convert DB strings to symbols with .to_sym and validate membership in ITEM_TYPES first.
  3. Add the new type to ITEM_TYPES (and the corresponding visibility scoping code) if support is genuinely needed.

Example fix

// before
helper.visible_item_ids_for_users(item.type_name, user_ids)

// after
type = item.type_name.to_sym
raise ArgumentError unless Courses::ItemVisibilityHelper::ITEM_TYPES.include?(type)
helper.visible_item_ids_for_users(type, user_ids)
Defensive patterns

Strategy: validation

Validate before calling

raise 'bad type' unless Courses::ItemVisibilityHelper::ITEM_TYPES.include?(type.to_sym)

Type guard

def known_item_type?(type)
  Courses::ItemVisibilityHelper::ITEM_TYPES.include?(type.to_sym)
end

Prevention

When it happens

Trigger: Calling visible_item_ids_for_users(:announcement, user_ids), :module_item, :file, or any symbol not in the frozen ITEM_TYPES list; passing a string 'quiz' instead of the :quiz symbol.

Common situations: Extending visibility reporting to a new content type without adding it to ITEM_TYPES; dynamic code deriving the item type from a DB string and not symbolizing/validating it; typos like :assingment.

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

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/aa267c2eaf9b240b. Report an issue: GitHub.

Appendix: source

Thrown at app/models/courses/item_visibility_helper.rb:27

# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# 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 Courses
  module ItemVisibilityHelper
    ITEM_TYPES = %i[assignment discussion page quiz].freeze

    def visible_item_ids_for_users(item_type, user_ids)
      # return all the item ids that are visible to _any_ of the users
      raise "unknown item type" unless ITEM_TYPES.include?(item_type)

      cache_visibilities_for_users(item_type, user_ids)
      user_ids.flat_map { |user_id| @cached_visibilities.dig(item_type, user_id) }.uniq
    end

    def cache_item_visibilities_for_user_ids(user_ids)
      ITEM_TYPES.each do |item_type|
        cache_visibilities_for_users(item_type, user_ids)
      end
    end

    def clear_cached_item_visibilities
      @cached_visibilities&.clear
    end

    private

    def cache_visibilities_for_users(item_type, user_ids)

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