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

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

Overview

This cop identifies use of ‘Regexp#match` or `String#match in a context where the integral return value of `=~` would do just as well.

Examples:

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

@good
method(str.match(/regex/))
return regex.match('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::BYTE_ORDER_MARK, 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, 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_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?, block_length, comment_line?, compatible_external_encoding_for?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, hard_to_type?, interpret_string_escapes, line_distance, line_range, move_pos, needs_escaping?, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, preceed?, range_between, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, to_string_literal, to_supported_styles, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



41
42
43
44
45
46
47
48
49
50
 
# File 'lib/rubocop/cop/performance/redundant_match.rb', line 41

def autocorrect(node)
  receiver, _method, arg = *node

  # Regexp#match can take a second argument, but this cop doesn't
  # register an offense in that case
  return unless arg.regexp_type?

  new_source = receiver.source + ' =~ ' + arg.source
  ->(corrector) { corrector.replace(node.source_range, new_source) }
end

#on_send(node) ⇒ Object 



34
35
36
37
38
39
 
# File 'lib/rubocop/cop/performance/redundant_match.rb', line 34

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, :expression, MSG)
end