Class: RuboCop::Cop::Lint::UnusedMethodArgument

Inherits:
Cop
  • Object
show all
Includes:
UnusedArgument
Defined in:
lib/rubocop/cop/lint/unused_method_argument.rb

Overview

This cop checks for unused method arguments.

Examples:


# bad

def some_method(used, unused, _unused_but_allowed)
  puts used
end

# good

def some_method(used, _unused, _unused_but_allowed)
  puts used
end

Constant Summary

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods included from UnusedArgument

#after_leaving_scope, #autocorrect, #join_force?

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, comment_line?, compatible_external_encoding_for?, directions, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_distance, line_range, move_pos, needs_escaping?, on_node, operator?, parentheses?, parenthesized_call?, preceed?, range_between, range_by_whole_lines, range_with_surrounding_comma, range_with_surrounding_space, same_line?, scrub_string, source_range, strip_quotes, stripped_source_upto, symbol_without_quote?, to_string_literal, to_supported_styles, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path, smart_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#check_argument(variable) ⇒ Object 



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# File 'lib/rubocop/cop/lint/unused_method_argument.rb', line 26

def check_argument(variable)
  return unless variable.method_argument?
  return if variable.keyword_argument? &&
            cop_config['AllowUnusedKeywordArguments']

  if cop_config['IgnoreEmptyMethods']
    _name, _args, body = *variable.scope.node
    return if body.nil?
  end

  super
end

#message(variable) ⇒ Object 



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# File 'lib/rubocop/cop/lint/unused_method_argument.rb', line 39

def message(variable)
  message = String.new("Unused method argument - `#{variable.name}`.")

  unless variable.keyword_argument?
    message << " If it's necessary, use `_` or `_#{variable.name}` " \
               "as an argument name to indicate that it won't be used."
  end

  scope = variable.scope
  all_arguments = scope.variables.each_value.select(&:method_argument?)

  if all_arguments.none?(&:referenced?)
    message << " You can also write as `#{scope.name}(*)` " \
               'if you want the method to accept any arguments ' \
               "but don't care about them."
  end

  message
end