puppetlabs/puppet · error · ArgumentError

Expected an Array of String, got a %{klass}

Error message

Expected an Array of String, got a %{klass}

What it means

Error "Expected an Array of String, got a %{klass}" thrown in puppetlabs/puppet.

Source

Thrown at lib/puppet/settings/server_list_setting.rb:26

  def print(value)
    if value.is_a?(Array)
      # turn into a string
      value.map { |item| item.join(":") }.join(",")
    else
      value
    end
  end

  def munge(value)
    servers = super
    servers.map! { |server|
      case server
      when String
        server.split(':')
      when Array
        server
      else
        raise ArgumentError, _("Expected an Array of String, got a %{klass}") % { klass: value.class }
      end
    }
  end
end

View on GitHub (pinned to e227c27540)

When it happens

Trigger: Thrown at lib/puppet/settings/server_list_setting.rb:26 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/8cd8a4dc90275c97. Report an issue: GitHub.