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Class: RuboCop::Cop::Style::RedundantFilterChain

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/redundant_filter_chain.rb

Overview

Identifies usages of any?, empty? or none? predicate methods chained to select/filter/find_all and change them to use predicate method instead.

Examples:

# bad
arr.select { |x| x > 1 }.any?

# good
arr.any? { |x| x > 1 }

# bad
arr.select { |x| x > 1 }.empty?
arr.select { |x| x > 1 }.none?

# good
arr.none? { |x| x > 1 }

# good
relation.select(:name).any?
arr.select { |x| x > 1 }.any?(&:odd?)

AllCops:ActiveSupportExtensionsEnabled: false (default)

# good
arr.select { |x| x > 1 }.many?

# good
arr.select { |x| x > 1 }.present?

AllCops:ActiveSupportExtensionsEnabled: true

# bad
arr.select { |x| x > 1 }.many?

# good
arr.many? { |x| x > 1 }

# bad
arr.select { |x| x > 1 }.present?

# good
arr.any? { |x| x > 1 }

Cop Safety Information:

  • This cop’s autocorrection is unsafe because array.select.any? evaluates all elements through the select method, while array.any? uses short-circuit evaluation. In other words, array.select.any? guarantees the evaluation of every element, but array.any? does not necessarily evaluate all of them.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#offense_range(select_node, predicate_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_filter_chain.rb', line 108

def offense_range(select_node, predicate_node)
  select_node.loc.selector.join(predicate_node.loc.selector)
end

#on_csend(node)

Alias for #on_send.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_filter_chain.rb', line 90

alias on_csend on_send

#on_send(node) Also known as: #on_csend

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_filter_chain.rb', line 81

def on_send(node)
  return if node.arguments? || node.block_literal?

  select_predicate?(node) do |select_node, filter_method|
    return if RAILS_METHODS.include?(filter_method) && !active_support_extensions_enabled?

    register_offense(select_node, node)
  end
end

#predicate_range(predicate_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_filter_chain.rb', line 112

def predicate_range(predicate_node)
  predicate_node.receiver.source_range.end.join(predicate_node.loc.selector)
end

#register_offense(select_node, predicate_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_filter_chain.rb', line 94

def register_offense(select_node, predicate_node)
  replacement = REPLACEMENT_METHODS[predicate_node.method_name]
  message = format(MSG, prefer: replacement,
                        first_method: select_node.method_name,
                        second_method: predicate_node.method_name)

  offense_range = offense_range(select_node, predicate_node)

  add_offense(offense_range, message: message) do |corrector|
    corrector.remove(predicate_range(predicate_node))
    corrector.replace(select_node.loc.selector, replacement)
  end
end

#select_predicate?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_filter_chain.rb', line 62

def_node_matcher :select_predicate?, <<~PATTERN
  (call
    {
      (block $(call _ {:select :filter :find_all}) ...)
      $(call _ {:select :filter :find_all} block_pass_type?)
    }
    ${:#{RESTRICT_ON_SEND.join(' :')}})
PATTERN