puppetlabs/puppet · error · ArgumentError

Parsing of type string '"%{type_string}"' failed with messag

Error message

Parsing of type string '"%{type_string}"' failed with message: <%{message}>.

What it means

When a dispatch signature is assembled, every String type reference is parsed with the Pops TypeParser. If parsing fails, internal_type_parse re-raises the parser's message wrapped in this ArgumentError. The error names the exact offending type string, so a typo or unbalanced bracket is easy to locate.

Source

Thrown at lib/puppet/functions.rb:595

    # Handles creation of a callable type from strings specifications of puppet
    # types and allows the min/max occurs of the given types to be given as one
    # or two integer values at the end.  The given block_type should be
    # Optional[Callable], Callable, or nil.
    #
    # @api private
    def create_callable(types, block_type, return_type, from, to)
      mapped_types = types.map do |t|
        t.is_a?(Puppet::Pops::Types::PAnyType) ? t : internal_type_parse(t, loader)
      end
      param_types = Puppet::Pops::Types::PTupleType.new(mapped_types, from > 0 && from == to ? nil : Puppet::Pops::Types::PIntegerType.new(from, to))
      return_type = internal_type_parse(return_type, loader) unless return_type.nil? || return_type.is_a?(Puppet::Pops::Types::PAnyType)
      Puppet::Pops::Types::PCallableType.new(param_types, block_type, return_type)
    end

    def internal_type_parse(type_string, loader)
      Puppet::Pops::Types::TypeParser.singleton.parse(type_string, loader)
    rescue StandardError => e
      raise ArgumentError, _("Parsing of type string '\"%{type_string}\"' failed with message: <%{message}>.\n") % {
        type_string: type_string,
        message: e.message
      }
    end
    private :internal_type_parse
  end

  # The LocalTypeAliasBuilder is used by the 'local_types' method to collect the individual
  # type aliases given by the function's author.
  #
  class LocalTypeAliasesBuilder
    attr_reader :local_types, :parser, :loader

    def initialize(loader, name)
      @loader = Puppet::Pops::Loader::PredefinedLoader.new(loader, :"local_function_#{name}", loader.environment)
      @local_types = []
      # get the shared parser used by puppet's compiler
      @parser = Puppet::Pops::Parser::EvaluatingParser.singleton()

View on GitHub (pinned to e227c27540)

Solutions

1. Copy the exact quoted type_string out of the message and fix it: check spelling against the Puppet type reference and balance all brackets.
2. Verify the corrected string parses: Puppet::Pops::Types::TypeParser.singleton.parse('YourType') in a console.
3. If the string references a local alias, make sure local_types declares it and that its own right-hand side is valid.
4. For third-party functions, match the module release to your Puppet version; type syntax support varies.

Example fix

# before
 param 'Strin', :s
 param 'Array[String', :xs

# after
 param 'String', :s
 param 'Array[String]', :xs

# Fail fast with your own message: pre-parse every type string used in dispatches
%w[String Integer Array[String] Optional[Hash]].each do |t|
  Puppet::Pops::Types::TypeParser.singleton.parse(t)
end

begin
  Puppet::Pops::Types::TypeParser.singleton.parse(candidate_type)
rescue StandardError => e
  raise ArgumentError, "fix type string '#{candidate_type}': #{e.message}"
end

When it happens

Trigger: param 'Strin', :s (typo), param 'Array[String', :xs (unbalanced bracket), or a self-referencing alias that the parser cannot resolve during parse. It usually surfaces nested inside 'Function Load Error' because create_function wraps it.

Common situations: Typos in type names; missing closing brackets after edits; using type aliases that are not in scope for the function's loader; Puppet version differences in supported type syntax.

Related errors

• A required parameter cannot be added after an optional param
• A required repeated parameter cannot be added after an optio
• Parameters cannot be added after a block parameter
• Parameters cannot be added after a repeated parameter
• Parameter name argument must be a Symbol. Got %{name_class}

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/45def4eb2bafcd28. Report an issue: GitHub.