Class: RuboCop::Cop::Style::GlobalStdStream

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/style/global_std_stream.rb

Overview

This cop enforces the use of `$stdout/$stderr/$stdin` instead of `STDOUT/STDERR/STDIN`. `STDOUT/STDERR/STDIN` are constants, and while you can actually reassign (possibly to redirect some stream) constants in Ruby, you'll get an interpreter warning if you do so.

Examples:

# bad
STDOUT.puts('hello')

hash = { out: STDOUT, key: value }

def m(out = STDOUT)
  out.puts('hello')
end

# good
$stdout.puts('hello')

hash = { out: $stdout, key: value }

def m(out = $stdout)
  out.puts('hello')
end

Constant Summary collapse

MSG =
'Use `%<gvar_name>s` instead of `%<const_name>s`.'
STD_STREAMS =
%i[STDIN STDOUT STDERR].to_set.freeze

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

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, joining_forces, lint?, match?, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

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

silence_warnings

Constructor Details

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

Instance Method Details

#const_to_gvar_assignment?(node, name) ⇒ Object


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# File 'lib/rubocop/cop/style/global_std_stream.rb', line 42

def_node_matcher :const_to_gvar_assignment?, <<~PATTERN
  (gvasgn %1 (const nil? _))
PATTERN

#on_const(node) ⇒ Object


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# File 'lib/rubocop/cop/style/global_std_stream.rb', line 46

def on_const(node)
  const_name = node.children[1]
  return unless STD_STREAMS.include?(const_name)

  gvar_name = gvar_name(const_name).to_sym
  return if const_to_gvar_assignment?(node.parent, gvar_name)

  add_offense(node, message: message(const_name)) do |corrector|
    corrector.replace(node, gvar_name)
  end
end