Class: RuboCop::Cop::Performance::RedundantMatch

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/performance/redundant_match.rb

Overview

This cop identifies the use of ‘Regexp#match` or `String#match`, which returns `#<MatchData>`/`nil`. The return value of `=~` is an integral index/`nil` and is more performant.

Examples:

# bad
do_something if str.match(/regex/)
while regex.match('str')
  do_something
end

# good
method(str =~ /regex/)
return value unless regex =~ 'str'

Constant Summary collapse

MSG = 
'Use `=~` in places where the `MatchData` returned by ' \
'`#match` will not be used.'.freeze

Constants included from Util

Util::ASGN_NODES, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, operator?, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens

Methods included from PathUtil

absolute?, match_path?, pwd, relative_path, reset_pwd, smart_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/redundant_match.rb', line 43

def autocorrect(node)
  # Regexp#match can take a second argument, but this cop doesn't
  # register an offense in that case
  return unless node.first_argument.regexp_type?

  new_source =
    node.receiver.source + ' =~ ' + node.first_argument.source

  ->(corrector) { corrector.replace(node.source_range, new_source) }
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/redundant_match.rb', line 35

def on_send(node)
  return unless match_call?(node) &&
                (!node.value_used? || only_truthiness_matters?(node)) &&
                !(node.parent && node.parent.block_type?)

  add_offense(node)
end