puppetlabs/puppet · error · ArgumentError

'%{format}' is not a supported format for type generation.

Error message

'%{format}' is not a supported format for type generation.

What it means

Raised from the `before_action` hook of the `--format` option in the `puppet generate types` face: the requested format is not in the allowlist `['pcore']`. Pcore is the only generation format that exists; the check runs before any generation work starts, so no files are written when it fires. The match is exact, so casing variants such as 'Pcore' are also rejected.

Source

Thrown at lib/puppet/face/generate.rb:38

      between different environments.
    EOT

    examples <<-'EOT'
      Generate Puppet type definitions for all custom resource types in the current environment:

          $ puppet generate types

      Generate Puppet type definitions for all custom resource types in the specified environment:

          $ puppet generate types --environment development
    EOT

    option '--format ' + _('<format>') do
      summary _('The generation output format to use. Supported formats: pcore.')
      default_to { 'pcore' }

      before_action do |_, _, options|
        raise ArgumentError, _("'%{format}' is not a supported format for type generation.") % { format: options[:format] } unless ['pcore'].include?(options[:format])
      end
    end

    option '--force' do
      summary _('Forces the generation of output files (skips up-to-date checks).')
      default_to { false }
    end

    when_invoked do |options|
      generator = Puppet::Generate::Type
      inputs = generator.find_inputs(options[:format].to_sym)
      environment = Puppet.lookup(:current_environment)

      # get the common output directory (in <envroot>/.resource_types) - create it if it does not exists
      # error if it exists and is not a directory
      #
      path_to_env = environment.configuration.path_to_env
      outputdir = File.join(path_to_env, '.resource_types')

View on GitHub (pinned to e227c27540)

Solutions

1. Omit `--format` entirely — it defaults to 'pcore'
2. Or pass the exact value: `puppet generate types --format pcore`
3. Remove format-selection logic from wrappers; there is no second format to choose

Example fix

# before
puppet generate types --format json
# after
puppet generate types --format pcore
# or simply
puppet generate types

fmt = options.fetch(:format, 'pcore')
raise ArgumentError, "unsupported format #{fmt}" unless %w[pcore].include?(fmt)

def supported_generate_format?(fmt)
  %w[pcore].include?(fmt.to_s)
end

When it happens

Trigger: `puppet generate types --format json` (or any value other than the exact string 'pcore'); wrappers exposing a configurable format and defaulting to something else.

Common situations: Scripts written against a speculative/imagined API; attempts to generate JSON schema or protobuf output that Puppet never supported; copy-paste from other tools' docs.

Related errors

• The output directory '%{outputdir}' exists and is not a dire
• Data Type Load Error for type '%{type_name}': %{message}
• a data type must have an interface
• a data type can only have one interface
• a data type can only have one implementation

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/fd7cd4e8d8ecf99d. Report an issue: GitHub.