instructure/canvas-lms · error · RuntimeError

Use Lti::ResourceLink#current_external_tool to lookup…

Error message

Use Lti::ResourceLink#current_external_tool to lookup associated tool

What it means

Lti::ResourceLink#context_external_tool is deliberately unimplemented: it always raises to force callers onto current_external_tool(context) instead. The legacy lookup is unsafe because tool reinstallation and content migrations can change tool IDs/domains, so a context-less, cached lookup can return the wrong (stale) tool. This is a developer-guard error, not a runtime failure of the lookup itself.

Solutions

1. Replace the call with resource_link.current_external_tool(context), passing the appropriate context (course, account, etc.).
2. Audit for other deprecated tool-lookup paths (e.g. accessing original_context_external_tool directly for runtime decisions) and route them through current_external_tool.
3. If you need the raw original tool record for non-runtime purposes, use original_context_external_tool explicitly and knowingly.
4. Update gems/plugins that call the old accessor to versions compatible with current_external_tool.

Example fix

// before
tool = resource_link.context_external_tool
// after
tool = resource_link.current_external_tool(course)

# ensure code paths use the safe accessor
unless resource_link.respond_to?(:current_external_tool)
  raise 'Canvas version without Lti::ResourceLink#current_external_tool; upgrade required'
end
tool = resource_link.current_external_tool(context)

def safe_external_tool(resource_link, context)
  return resource_link.current_external_tool(context) if resource_link.respond_to?(:current_external_tool)
  raise ArgumentError, 'use current_external_tool(context) for tool lookup; context_external_tool is unsupported'
end

begin
  tool = resource_link.current_external_tool(context)
rescue NoMethodError => e
  raise "ResourceLink tool lookup unavailable (#{e.message}); verify Canvas/gem version"
end

When it happens

Trigger: Any code calling resource_link.context_external_tool — e.g. plugin/custom code copied from pre-current_external_tool examples, or code that calls a method which internally uses the deprecated accessor. It raises unconditionally on every call.

Common situations: Upgrading custom LTI integrations after Canvas refactored ResourceLink tool lookup; copying sample code from old documentation; gems/plugins updated to newer Canvas where the accessor became a hard error; developers assuming context_external_tool is a plain association reader.

Understand the failure class

Background: "is deprecated and will be removed" — deprecation warnings for old API names, keywords, and options, and how to migrate before the removal release — this error's family across 29 libraries.

Related errors

• Unable to find external tool to import content.
• Access token expired
• Access token invalid - signature likely incorrect
• assignment_invalid
• Assignment not configured for external tool launches

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/629a45861d414cd1. Report an issue: GitHub.

Appendix: source

Thrown at app/models/lti/resource_link.rb:73

    super
  end

  def self.create_with(context, tool, custom_params = nil, url = nil, title = nil, lti_1_1_id: nil)
    return if context.nil? || tool.nil?

    context.lti_resource_links.create!(
      custom: Lti::DeepLinkingUtil.validate_custom_params(custom_params),
      context_external_tool: tool,
      url:,
      title:,
      lti_1_1_id:
    )
  end

  def context_external_tool
    # Use 'current_external_tool' to lookup the tool in a way that is safe with
    # tool reinstallation and content migrations
    raise "Use Lti::ResourceLink#current_external_tool to lookup associated tool"
  end

  def current_external_tool(context)
    Lti::ToolFinder.from_url(
      original_context_external_tool.url || original_context_external_tool.domain,
      context,
      preferred_tool_id: original_context_external_tool.id,
      only_1_3: true
    )
  end

  def self.find_or_initialize_for_context_and_lookup_uuid(
    context:,
    lookup_uuid:,
    custom: nil,
    url: nil,
    context_external_tool: nil,
    context_external_tool_launch_url: nil

View on GitHub (pinned to 1c9f0bb801)