puppetlabs/puppet · error · ArgumentError

PP syntax checker: the syntax identifier must be a String, e

Error message

PP syntax checker: the syntax identifier must be a String, e.g. pp

What it means

Despite the message text ('must be a String, e.g. pp'), this ArgumentError fires unless syntax is exactly the String 'pp'. The guard is `unless syntax == 'pp'`, so a Symbol :pp, 'PP', 'pp ', or any other valid String like 'ruby' all raise. The checker only handles Puppet Language source, so the identifier must match its registry key 'pp' exactly.

Source

Thrown at lib/puppet/syntax_checkers/pp.rb:19

# frozen_string_literal: true

# A syntax checker for JSON.
# @api public
require_relative '../../puppet/syntax_checkers'
class Puppet::SyntaxCheckers::PP < Puppet::Plugins::SyntaxCheckers::SyntaxChecker
  # Checks the text for Puppet Language syntax issues and reports them to the given acceptor.
  #
  # Error messages from the checker are capped at 100 chars from the source text.
  #
  # @param text [String] The text to check
  # @param syntax [String] The syntax identifier in mime style (only accepts 'pp')
  # @param acceptor [#accept] A Diagnostic acceptor
  # @param source_pos [Puppet::Pops::Adapters::SourcePosAdapter] A source pos adapter with location information
  # @api public
  #
  def check(text, syntax, acceptor, source_pos)
    raise ArgumentError, _("PP syntax checker: the text to check must be a String.") unless text.is_a?(String)
    raise ArgumentError, _("PP syntax checker: the syntax identifier must be a String, e.g. pp") unless syntax == 'pp'
    raise ArgumentError, _("PP syntax checker: invalid Acceptor, got: '%{klass}'.") % { klass: acceptor.class.name } unless acceptor.is_a?(Puppet::Pops::Validation::Acceptor)

    begin
      Puppet::Pops::Parser::EvaluatingParser.singleton.parse_string(text)
    rescue => e
      # Cap the message to 100 chars and replace newlines
      msg = _("PP syntax checker: \"%{message}\"") % { message: e.message().slice(0, 500).gsub(/\r?\n/, "\\n") }

      # TODO: improve the pops API to allow simpler diagnostic creation while still maintaining capabilities
      # and the issue code. (In this case especially, where there is only a single error message being issued).
      #
      issue = Puppet::Pops::Issues.issue(:ILLEGAL_PP) { msg }
      acceptor.accept(Puppet::Pops::Validation::Diagnostic.new(:error, issue, source_pos.file, source_pos, {}))
    end
  end
end

View on GitHub (pinned to e227c27540)

Solutions

1. Pass the exact literal 'pp' (lowercase String)
2. Normalize before dispatch: syntax.to_s.downcase.strip
3. Route by the checker registry key (Puppet.lookup(:plugins)[Puppet::Plugins::SyntaxCheckers::SYNTAX_CHECKERS_KEY]) instead of guessing a checker per identifier

Example fix

# before
checker.check(text, :pp, acceptor, pos) # => ArgumentError

# after
checker.check(text, 'pp', acceptor, pos)

syntax = syntax.to_s.downcase.strip if syntax.respond_to?(:to_s)
raise ArgumentError, "unsupported syntax #{syntax.inspect}; PP checker accepts 'pp' only" unless syntax == 'pp'

When it happens

Trigger: Calling the PP checker with :pp (Symbol), 'PP', or dispatching a checker by mime-style identifier and routing 'epp'/'ruby' content to the PP checker. Also hit when a syntax tag is built dynamically (string interpolation with trailing whitespace or newlines).

Common situations: Code that normalizes syntax tags with .upcase or .to_sym, generic checker-dispatch frameworks that try each registered checker in turn, or heredoc tags with invisible whitespace copied from documentation.

Understand the failure class

Background: Invalid argument type errors: "must be of type string", "expected X, got Y", and ERR_INVALID_ARG_TYPE explained — this error's family across 15 libraries.

Related errors

• PP syntax checker: the text to check must be a String.
• PP syntax checker: invalid Acceptor, got: '%{klass}'.
• EPP syntax checker: invalid Acceptor, got: '%{klass}'.
• Json syntax checker: the text to check must be a String.
• Json syntax checker: the syntax identifier must be a String,

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/f2282fc6f21ef5bc. Report an issue: GitHub.