Class: RuboCop::Cop::Lint::UnderscorePrefixedVariableName

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/lint/underscore_prefixed_variable_name.rb

Overview

This cop checks for underscore-prefixed variables that are actually used.

Since block keyword arguments cannot be arbitrarily named at call sites, the ‘AllowKeywordBlockArguments` will allow use of underscore- prefixed block keyword arguments.

Examples:

AllowKeywordBlockArguments: false (default)


# bad

[1, 2, 3].each do |_num|
  do_something(_num)
end

query(:sales) do |_id:, revenue:, cost:|
  {_id: _id, profit: revenue - cost}
end

# good

[1, 2, 3].each do |num|
  do_something(num)
end

[1, 2, 3].each do |_num|
  do_something # not using `_num`
end

AllowKeywordBlockArguments: true


# good

query(:sales) do |_id:, revenue:, cost:|
  {_id: _id, profit: revenue - cost}
end

Constant Summary collapse

MSG = 
'Do not use prefix `_` for a variable that is used.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#add_global_offense, #add_offense, autocorrect_incompatible_with, badge, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

add_parentheses, args_begin, args_end, begins_its_line?, comment_line?, comment_lines?, double_quotes_required?, escape_string, first_part_of_call_chain, indent, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, hidden_dir?, hidden_file?, hidden_file_in_not_hidden_dir?, match_path?, maybe_hidden_file?, relative_path, smart_path

Constructor Details

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

Class Method Details

.joining_forces ⇒ Object 



46
47
48
 
# File 'lib/rubocop/cop/lint/underscore_prefixed_variable_name.rb', line 46

def self.joining_forces
  VariableForce
end

Instance Method Details

#after_leaving_scope(scope, _variable_table) ⇒ Object 



50
51
52
53
54
 
# File 'lib/rubocop/cop/lint/underscore_prefixed_variable_name.rb', line 50

def after_leaving_scope(scope, _variable_table)
  scope.variables.each_value do |variable|
    check_variable(variable)
  end
end

#check_variable(variable) ⇒ Object 



56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
 
# File 'lib/rubocop/cop/lint/underscore_prefixed_variable_name.rb', line 56

def check_variable(variable)
  return unless variable.should_be_unused?
  return if variable.references.none?(&:explicit?)
  return if allowed_keyword_block_argument?(variable)

  node = variable.declaration_node

  location = if node.match_with_lvasgn_type?
               node.children.first.source_range
             else
               node.loc.name
             end

  add_offense(location)
end