puppetlabs/puppet · error · ArgumentError

The code loaded from

Error message

The code loaded from %{source_ref} produced mis-matched name, expected 'function_%{type_name}', got '%{created_name}'

What it means

Raised by RubyLegacyFunctionInstantiator when the loaded function's info Hash reports a different function name than expected. The check compares func_info[:name] (set by newfunction) against "function_#{typed_name.name}", so the symbol passed to newfunction must match the file name: double.rb must call newfunction(:double, ...).

Solutions

1. Make the newfunction symbol match the file name exactly
2. Rename the file to match the symbol if the symbol is the desired name
3. Re-check after any rename so file name and symbol stay in sync

Example fix

# before - lib/puppet/parser/functions/bar.rb
module Puppet::Parser::Functions
  newfunction(:baz, :type => :rvalue) { |a| a[0] }
end

# after - lib/puppet/parser/functions/bar.rb
module Puppet::Parser::Functions
  newfunction(:bar, :type => :rvalue) { |a| a[0] }
end

begin
  fn = loader.load_typed(typed_name)
rescue ArgumentError => e
  raise unless e.message.include?("expected 'function_")
  warn "legacy function name mismatch: #{e.message}"
end

When it happens

Trigger: File bar.rb calls newfunction(:baz, ...): the returned Hash's :name is 'function_baz' while the loader expects 'function_bar' (typed name derived from the file name).

Common situations: Renaming a legacy function file without updating the newfunction symbol; copy-pasted function files; case differences in the symbol.

Related errors

• Illegal legacy function definition! The code loaded from
• The code loaded from
• The code loaded from
• The code loaded from
• The code loaded from

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/508ab5329cb65924. Report an issue: GitHub.

Appendix: source

Thrown at lib/puppet/pops/loader/ruby_legacy_function_instantiator.rb:51

    # Avoid reloading the function if already loaded via one of the APIs that trigger 3x function loading
    # Check if function is already loaded the 3x way (and obviously not the 4x way since we would not be here in the
    # first place.
    environment = Puppet.lookup(:current_environment)
    func_info = Puppet::Parser::Functions.environment_module(environment).get_function_info(typed_name.name.to_sym)
    if func_info.nil?
      # This will do the 3x loading and define the "function_<name>" and "real_function_<name>" methods
      # in the anonymous module used to hold function definitions.
      #
      func_info = eval(ruby_code_string, here, source_ref, 1) # rubocop:disable Security/Eval

      # Validate what was loaded
      unless func_info.is_a?(Hash)
        # TRANSLATORS - the word 'newfunction' should not be translated as it is a method name.
        raise ArgumentError, _("Illegal legacy function definition! The code loaded from %{source_ref} did not return the result of calling 'newfunction'. Got '%{klass}'") % { source_ref: source_ref, klass: func_info.class }
      end

      unless func_info[:name] == "function_#{typed_name.name()}"
        raise ArgumentError, _("The code loaded from %{source_ref} produced mis-matched name, expected 'function_%{type_name}', got '%{created_name}'") % {
          source_ref: source_ref, type_name: typed_name.name, created_name: func_info[:name]
        }
      end
    end

    created = Puppet::Functions::Function3x.create_function(typed_name.name(), func_info, loader_for_function)

    # create the function instance - it needs closure (scope), and loader (i.e. where it should start searching for things
    # when calling functions etc.
    # It should be bound to global scope

    # Sets closure scope to nil, to let it be picked up at runtime from Puppet.lookup(:global_scope)
    # If function definition used the loader from the binding to create a new loader, that loader wins
    created.new(nil, loader_for_function)
  end

  # Produces a binding where the given loader is bound as a local variable (loader_injected_arg). This variable can be used in loaded
  # ruby code - e.g. to call Puppet::Function.create_loaded_function(:name, loader,...)

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