Class: RuboCop::Cop::Style::PartitionInsteadOfDoubleSelect

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

Overview

Checks for consecutive calls to select/filter/find_all and reject on the same receiver with the same block body, where partition could be used instead. Also detects two select or two reject calls where one block negates the other with ‘!`. Using partition reduces two collection traversals to one.

Examples:

# bad
positives = array.select { |x| x > 0 }
negatives = array.reject { |x| x > 0 }

# bad
positives = array.filter { |x| x > 0 }
negatives = array.reject { |x| x > 0 }

# bad
negatives = array.reject { |x| x > 0 }
positives = array.select { |x| x > 0 }

# bad
positives = array.select(&:positive?)
negatives = array.reject(&:positive?)

# bad
positives = array.select(&:positive?)
negatives = array.reject { |x| x.positive? }

# bad
positives = array.select { |x| x.positive? }
non_positives = array.select { |x| !x.positive? }

# good
positives, negatives = array.partition { |x| x > 0 }

# good
positives, non_positives = array.partition { |x| x.positive? }

# good
positives, negatives = array.partition(&:positive?)

Constant Summary collapse

MSG = 
'Use `partition` instead of consecutive `%<first>s` and `%<second>s` calls.'
SELECT_METHODS = 
i[select filter find_all].freeze
CANDIDATE_METHODS = 
(SELECT_METHODS + i[reject]).to_set.freeze
RESTRICT_ON_SEND = 
(SELECT_METHODS + i[reject]).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

#on_block(node) ⇒ Object Also known as: on_numblock, on_itblock 



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# File 'lib/rubocop/cop/style/partition_instead_of_double_select.rb', line 71

def on_block(node)
  return unless CANDIDATE_METHODS.include?(node.method_name)

  find_and_register_offense(node)
end

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



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# File 'lib/rubocop/cop/style/partition_instead_of_double_select.rb', line 79

def on_send(node)
  return unless node.last_argument&.block_pass_type?

  find_and_register_offense(node)
end

#symbol_proc_method?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/partition_instead_of_double_select.rb', line 67

def_node_matcher :symbol_proc_method?, "(block _ (args (arg _name)) (send (lvar _name) $_method_name))\n"