puppetlabs/puppet · error · Puppet::Error

title patterns that use procs are not supported.

Error message

title patterns that use procs are not supported.

What it means

'puppet generate types' (run during r10k/Code Manager deploys for environment isolation) converts each resource type's title_patterns into a pcore type definition in generated Puppet code. A title pattern may bind regex captures to namevars via procs, but a proc cannot be rendered into the DSL, so generation aborts with Puppet::Error when any binding entry is a [name, proc] pair instead of a plain [name].

Source

Thrown at lib/puppet/generate/models/type/type.rb:48

          attr_reader :capability

          # Initializes a type model.
          # @param type [Puppet::Type] The Puppet type to model.
          # @return [void]
          def initialize(type)
            @name = Puppet::Pops::Types::StringConverter.convert(type.name.to_s, '%p')
            @doc = type.doc.strip
            @properties = type.properties.map { |p| Property.new(p) }
            @parameters = type.parameters.map do |name|
              Property.new(type.paramclass(name))
            end
            sc = Puppet::Pops::Types::StringConverter.singleton
            @title_patterns = type.title_patterns.to_h do |mapping|
              [
                sc.convert(mapping[0], '%p'),
                sc.convert(mapping[1].map do |names|
                  next if names.empty?
                  raise Puppet::Error, _('title patterns that use procs are not supported.') unless names.size == 1

                  names[0].to_s
                end, '%p')
              ]
            end
            @isomorphic = type.isomorphic?
            # continue to emit capability as false when rendering the ERB
            # template, so that pcore modules generated prior to puppet7 can be
            # read by puppet7 and vice-versa.
            @capability = false
          end

          def render(template)
            template.result(binding)
          end
        end
      end
    end

View on GitHub (pinned to e227c27540)

Solutions

1. Upgrade the module to a version whose type supports pcore generation (many maintainers replaced proc-based title_patterns).
2. If the proc is a pass-through, patch the type to bind without a proc: [[:namevar]] instead of [[:namevar, proc { |s| s }]].
3. If the type genuinely needs capture transforms, report it to the maintainer and exclude the module from generate types until fixed.
4. Verify the fix by re-running 'puppet generate types' in the environment directory and checking the generated .pp.

Example fix

# lib/puppet/type/foobar.rb - before
newtype(:foobar) do
  def self.title_patterns
    [[%r{^(.*)$}, [[:name, proc { |s| s }]]]]
  end
end

# after
newtype(:foobar) do
  def self.title_patterns
    [[%r{^(.*)$}, [[:name]]]]
  end
end

# before `puppet generate types`, scan loaded types for proc title patterns
require 'puppet'

bad = Puppet::Type.loadall(Puppet::Node::Environment.remote('production'))
  .map { |t| Puppet::Type.type(t) }
  .flat_map { |t| (t.respond_to?(:title_patterns) ? t.title_patterns : []).map { |(_, binds)| binds } }
  .flatten(1)
  .select { |b| b.is_a?(Array) && b.size == 2 }

abort 'types with proc title_patterns cannot be generated' unless bad.empty?

begin
  Puppet::Application[:generate].run_command('types')
rescue Puppet::Error => e
  raise if e.message !~ /title patterns that use procs/
  warn "skipping type generation: #{e.message}"
end

When it happens

Trigger: An environment contains a native type whose self.title_patterns returns mappings like [[%r{^(.*)/(.*)$}, [[:user, proc { |s| s }], [:group, proc { |s| s }]]]] (entry size 2), and 'puppet generate types' runs — either manually or as a Code Manager/r10k post-deploy hook.

Common situations: Composite-namevar custom types (titles like 'path/line') in modules deployed to Puppet Enterprise with environment isolation; older module versions written before pcore support; upgrading Puppet 5.x to 6/7 where generate-types became a standard deploy step and the deploy starts failing.

Related errors

• 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
• attempt to #{action} #{type_name} annotation declared on #{o

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/c865feefaf4816c0. Report an issue: GitHub.