Class: RuboCop::Cop::Lint::HashNewWithKeywordArgumentsAsDefault

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

Overview

Checks for the deprecated use of keyword arguments as a default in ‘Hash.new`.

This usage raises a warning in Ruby 3.3 and results in an error in Ruby 3.4. In Ruby 3.4, keyword arguments will instead be used to change the behavior of a hash. For example, the capacity option can be passed to create a hash with a certain size if you know it in advance, for better performance.

NOTE: The following corner case may result in a false negative when upgrading from Ruby 3.3 or earlier, but it is intentionally not detected to respect the expected usage in Ruby 3.4.

source,ruby

Hash.new(capacity: 42)

Examples:


# bad
Hash.new(key: :value)

# good
Hash.new({key: :value})

Constant Summary collapse

MSG = 
'Use a hash literal instead of keyword arguments.'
RESTRICT_ON_SEND = 
%i[new].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, 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?, #autocorrect_with_disable_uncorrectable?, #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

#hash_new(node) ⇒ Object 



36
37
38
 
# File 'lib/rubocop/cop/lint/hash_new_with_keyword_arguments_as_default.rb', line 36

def_node_matcher :hash_new, <<~PATTERN
  (send (const {nil? (cbase)} :Hash) :new $[hash !braces?])
PATTERN

#on_send(node) ⇒ Object 



40
41
42
43
44
45
46
47
48
49
50
51
 
# File 'lib/rubocop/cop/lint/hash_new_with_keyword_arguments_as_default.rb', line 40

def on_send(node)
  return unless (first_argument = hash_new(node))

  if first_argument.pairs.one?
    key = first_argument.pairs.first.key
    return if key.respond_to?(:value) && key.value == :capacity
  end

  add_offense(first_argument) do |corrector|
    corrector.wrap(first_argument, '{', '}')
  end
end