puppetlabs/puppet · error · ArgumentError

%{option} already has a before_action set

Error message

%{option} already has a before_action set

What it means

OptionBuilder#before_action allows exactly one hook per option: if `@option.before_action` is already set, a second call raises (lib/puppet/interface/option_builder.rb:51). Faces have no hook-chaining semantics, so the duplicate declaration is rejected instead of merged. The error surfaces when the face file is loaded.

Source

Thrown at lib/puppet/interface/option_builder.rb:51

  # Override some methods that deal in blocks, not objects.

  # Sets a block to be executed when an action is invoked before the
  # main action code. This is most commonly used to validate an option.
  # @yieldparam action [Puppet::Interface::Action] The action being
  #   invoked
  # @yieldparam args [Array] The arguments given to the action
  # @yieldparam options [Hash<Symbol=>Object>] Any options set
  # @api public
  # @dsl Faces
  def before_action(&block)
    unless block
      # TRANSLATORS 'before_action' is a method name and should not be translated
      raise ArgumentError, _("%{option} before_action requires a block") % { option: @option }
    end
    if @option.before_action
      # TRANSLATORS 'before_action' is a method name and should not be translated
      raise ArgumentError, _("%{option} already has a before_action set") % { option: @option }
    end
    unless block.arity == 3 then
      # TRANSLATORS 'before_action' is a method name and should not be translated
      raise ArgumentError, _("before_action takes three arguments, action, args, and options")
    end

    @option.before_action = block
  end

  # Sets a block to be executed after an action is invoked.
  # !(see before_action)
  # @api public
  # @dsl Faces
  def after_action(&block)
    unless block
      # TRANSLATORS 'after_action' is a method name and should not be translated
      raise ArgumentError, _("%{option} after_action requires a block") % { option: @option }
    end

View on GitHub (pinned to e227c27540)

Solutions

1. Merge both bodies into a single `before_action` block
2. Delete the stale hook after moving validation elsewhere
3. If two concerns are distinct, keep one in before_action and move the other to after_action (different timing, different semantics)

Example fix

# before
option "--foo" do
  before_action { |a, args, opts| check_a(opts) }
  before_action { |a, args, opts| check_b(opts) }
end

# after
option "--foo" do
  before_action do |a, args, opts|
    check_a(opts)
    check_b(opts)
  end
end

# before registering a hook on an Option object
raise ArgumentError, 'before_action already set' if opt.before_action
opt.before_action = proc { |action, args, options| check(options) }

When it happens

Trigger: Two `before_action` blocks in the same option block; a helper invoked from the option block that itself calls before_action; iterating over validation rules and registering the hook twice.

Common situations: Copy-pasted option blocks that both carry hooks; refactoring that moves a hook but leaves the original behind; mixin modules contributing an extra hook.

Related errors

• %{option} already has an after_action set
• %{option} already has a default value
• %{name} can't be optional and have a default value
• default value for %{name} is a %{class_name}, not a proc
• before action hook for %{name} is a %{class_name}, not a pro

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/61df14cb2b240f79. Report an issue: GitHub.