Class: RuboCop::Cop::Style::SelectByRegexp

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

Overview

Looks for places where a subset of an Enumerable (array, range, set, etc.; see note below) is calculated based on a Regexp match, and suggests grep or grep_v instead.

NOTE: Hashes do not behave as you may expect with grep, which means that hash.grep is not equivalent to hash.select. Although RuboCop is limited by static analysis, this cop attempts to avoid registering an offense when the receiver is a hash (hash literal, Hash.new, ‘Hash#[]`, or to_h/to_hash).

NOTE: grep and grep_v were optimized when used without a block in Ruby 3.0, but may be slower in previous versions. See bugs.ruby-lang.org/issues/17030

Examples:

# bad (select, filter, or find_all)
array.select { |x| x.match? /regexp/ }
array.select { |x| /regexp/.match?(x) }
array.select { |x| x =~ /regexp/ }
array.select { |x| /regexp/ =~ x }

# bad (reject)
array.reject { |x| x.match? /regexp/ }
array.reject { |x| /regexp/.match?(x) }
array.reject { |x| x =~ /regexp/ }
array.reject { |x| /regexp/ =~ x }

# good
array.grep(regexp)
array.grep_v(regexp)

Constant Summary collapse

MSG = 
'Prefer `%<replacement>s` to `%<original_method>s` with a regexp match.'
RESTRICT_ON_SEND = 
i[select filter find_all reject].freeze
REPLACEMENTS = 
{ select: 'grep', filter: 'grep', find_all: 'grep', reject: 'grep_v' }.freeze
OPPOSITE_REPLACEMENTS = 
{
  select: 'grep_v', filter: 'grep_v', find_all: 'grep_v', reject: 'grep'
}.freeze
REGEXP_METHODS = 
i[match? =~ !~].to_set.freeze

Constants included from RangeHelp

RangeHelp::BYTE_ORDER_MARK, RangeHelp::NOT_GIVEN

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_gem_version, #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

#calls_lvar?(node, name) ⇒ Object 



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# File 'lib/rubocop/cop/style/select_by_regexp.rb', line 82

def_node_matcher :calls_lvar?, "{\n  (send (lvar %1) ...)\n  (send ... (lvar %1))\n  (match-with-lvasgn regexp (lvar %1))\n}\n"

#creates_hash?(node) ⇒ Object

Returns true if a node appears to return a hash



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# File 'lib/rubocop/cop/style/select_by_regexp.rb', line 68

def_node_matcher :creates_hash?, "{\n  (call (const _ :Hash) {:new :[]} ...)\n  (block (call (const _ :Hash) :new ...) ...)\n  (call _ { :to_h :to_hash } ...)\n}\n"

#env_const?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/select_by_regexp.rb', line 77

def_node_matcher :env_const?, "(const {nil? cbase} :ENV)\n"

#on_send(node) ⇒ Object Also known as: on_csend

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity



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# File 'lib/rubocop/cop/style/select_by_regexp.rb', line 91

def on_send(node)
  return if target_ruby_version < 2.6 && node.method?(:filter)
  return unless (block_node = node.block_node)
  return if block_node.body&.begin_type?
  return if receiver_allowed?(block_node.receiver)
  return unless (regexp_method_send_node = extract_send_node(block_node))
  return if match_predicate_without_receiver?(regexp_method_send_node)

  replacement = replacement(regexp_method_send_node, node)
  return if target_ruby_version <= 2.2 && replacement == 'grep_v'

  regexp = find_regexp(regexp_method_send_node, block_node)

  register_offense(node, block_node, regexp, replacement)
end

#regexp_match?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/select_by_regexp.rb', line 58

def_node_matcher :regexp_match?, "{\n  (block call (args (arg $_)) ${(send _ %REGEXP_METHODS _) match-with-lvasgn})\n  (numblock call $1 ${(send _ %REGEXP_METHODS _) match-with-lvasgn})\n  (itblock call $_ ${(send _ %REGEXP_METHODS _) match-with-lvasgn})\n}\n"