Class: RuboCop::Cop::Style::HashExcept

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector, TargetRubyVersion
Includes:
RangeHelp
Defined in:
lib/rubocop/cop/style/hash_except.rb

Overview

This cop checks for usages of `Hash#reject`, `Hash#select`, and `Hash#filter` methods that can be replaced with `Hash#except` method.

This cop should only be enabled on Ruby version 3.0 or higher. (`Hash#except` was added in Ruby 3.0.)

For safe detection, it is limited to commonly used string and symbol comparisons when used `==`. And do not check `Hash#delete_if` and `Hash#keep_if` to change receiver object.

Examples:


# bad
{foo: 1, bar: 2, baz: 3}.reject {|k, v| k == :bar }
{foo: 1, bar: 2, baz: 3}.select {|k, v| k != :bar }
{foo: 1, bar: 2, baz: 3}.filter {|k, v| k != :bar }

# good
{foo: 1, bar: 2, baz: 3}.except(:bar)

Constant Summary collapse

MSG =
'Use `%<prefer>s` instead.'
RESTRICT_ON_SEND =
%i[reject select filter].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from TargetRubyVersion

minimum_target_ruby_version, required_minimum_ruby_version, support_target_ruby_version?

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?, #message, #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

#bad_method?(node) ⇒ Object


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# File 'lib/rubocop/cop/style/hash_except.rb', line 37

def_node_matcher :bad_method?, <<~PATTERN
  (block
    (send _ _)
    (args
      (arg _)
      (arg _))
    (send
      _ {:== :!= :eql?} _))
PATTERN

#on_send(node) ⇒ Object


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# File 'lib/rubocop/cop/style/hash_except.rb', line 47

def on_send(node)
  block = node.parent
  return unless bad_method?(block) && semantically_except_method?(node, block)

  except_key = except_key(block)
  return if except_key.nil? || !safe_to_register_offense?(block, except_key)

  range = offense_range(node)
  preferred_method = "except(#{except_key.source})"

  add_offense(range, message: format(MSG, prefer: preferred_method)) do |corrector|
    corrector.replace(range, preferred_method)
  end
end