puppetlabs/puppet · error · ArgumentError

Purging resources of type %{res_type} is not supported, sinc

Error message

Purging resources of type %{res_type} is not supported, since they cannot be queried from the system

What it means

`resources { <type>: purge => true }` can only purge types that can enumerate themselves: the type class must respond to `.instances` (lib/puppet/type/resources.rb:36), because purging diffs the catalog against the system state. Types with no self-query mechanism raise ArgumentError "Purging resources of type ... is not supported".

Source

Thrown at lib/puppet/type/resources.rb:36

      raise ArgumentError, _("Could not find resource type '%{name}'") % { name: name } unless Puppet::Type.type(name)
    end

    munge(&:to_s)
  end

  newparam(:purge, :boolean => true, :parent => Puppet::Parameter::Boolean) do
    desc "Whether to purge unmanaged resources.  When set to `true`, this will
      delete any resource that is not specified in your configuration and is not
      autorequired by any managed resources. **Note:** The `ssh_authorized_key`
      resource type can't be purged this way; instead, see the `purge_ssh_keys`
      attribute of the `user` type."

    defaultto :false

    validate do |value|
      if munge(value)
        unless @resource.resource_type.respond_to?(:instances)
          raise ArgumentError, _("Purging resources of type %{res_type} is not supported, since they cannot be queried from the system") % { res_type: @resource[:name] }
        end
        raise ArgumentError, _("Purging is only supported on types that accept 'ensure'") unless @resource.resource_type.validproperty?(:ensure)
      end
    end
  end

  newparam(:unless_system_user) do
    desc "This keeps system users from being purged.  By default, it
      does not purge users whose UIDs are less than the minimum UID for the system (typically 500 or 1000), but you can specify
      a different UID as the inclusive limit."

    newvalues(:true, :false, /^\d+$/)

    munge do |value|
      case value
      when /^\d+/
        Integer(value)
      when :true, true

View on GitHub (pinned to e227c27540)

Solutions

Remove `purge` (or set it false) for that type and manage its instances explicitly
For custom types, implement `def self.instances` returning one resource per system instance
For ssh_authorized_key, use `purge_ssh_keys` on the user type instead

Example fix

# before
resources { 'exec':
  purge => true,
}

# after
# exec cannot be enumerated; declare the execs you want instead
exec { 'run-backup':
  command => '/usr/local/bin/backup.sh',
}

Defensive patterns

Strategy: validation

Validate before calling

# only emit a purge declaration for enumerable types
t = Puppet::Type.type(type_name.to_sym)
if t&.respond_to?(:instances)
  # ... emit resources { type_name: purge => true }
end

Type guard

def purgeable?(type_name)
  t = Puppet::Type.type(type_name.to_sym)
  !t.nil? && t.respond_to?(:instances) && t.validproperty?(:ensure)
end

Try / catch

begin
  Puppet::Type.type(:resources).new(name: 'exec', purge: true)
rescue ArgumentError => e
  raise unless e.message.include?('cannot be queried')
  # drop purge for this type
end

Prevention

Check a type supports instances (and ensure) before writing purge declarations
When writing custom types, always implement self.instances
Prefer explicit resource management over purge for non-enumerable types

When it happens

Trigger: `resources { 'exec': purge => true }` (exec cannot be enumerated); purging any custom type whose author only defined properties/params without `def self.instances`; purging built-in meta-only types.

Common situations: Blanket 'purge everything unmanaged' profiles looped over many types; custom types written without instances(); trying to purge ssh_authorized_key via resources instead of the user type's purge_ssh_keys.

Related errors

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/f5fcb6537bc58bb7. Report an issue: GitHub.