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

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
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.
Hash.new(capacity: 42)

Examples:

# bad
Hash.new(key: :value)

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

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns a url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?,
#target_gem_version

Returns a gems locked versions (i.e.

#target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#hash_new(node)

[ GitHub ]

  
# 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)

[ GitHub ]

  
# 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