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Class: RuboCop::Cop::Style::CombinableLoops

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:
self, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/combinable_loops.rb

Overview

Checks for places where multiple consecutive loops over the same data can be combined into a single loop. It is very likely that combining them will make the code more efficient and more concise.

Examples:

# bad
def method
  items.each do |item|
    do_something(item)
  end

  items.each do |item|
    do_something_else(item)
  end
end

# good
def method
  items.each do |item|
    do_something(item)
    do_something_else(item)
  end
end

# bad
def method
  for item in items do
    do_something(item)
  end

  for item in items do
    do_something_else(item)
  end
end

# good
def method
  for item in items do
    do_something(item)
    do_something_else(item)
  end
end

# good
def method
  each_slice(2) { |slice| do_something(slice) }
  each_slice(3) { |slice| do_something(slice) }
end

Cop Safety Information:

  • The cop is unsafe, because the first loop might modify state that the second loop depends on; these two aren’t combinable.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

support_autocorrect?

::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.
.builtin?

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

Cops (other than builtin) are encouraged to implement this.
.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

::RuboCop::Cop::Base - Inherited

#active_support_extensions_enabled?, #always_autocorrect?, #config, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #processed_source, #target_satisfies_all_gem_version_requirements?

::RuboCop::Cop::AutocorrectLogic - Included

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

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, #use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

#disable_offense, #disable_offense_at_end_of_line, #disable_offense_before_and_after, #disable_offense_with_eol_or_surround_comment, #max_line_length,
#range_by_lines

Expand the given range to include all of any lines it covers.
#range_of_first_line, #surrounding_heredoc, #surrounding_percent_array

::RuboCop::Cop::IgnoredNode - Included

#ignore_node, #ignored_node?, #part_of_ignored_node?, #ignored_nodes

Constructor Details

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

Instance Method Details

#collection_looping_method?(node) ⇒ Boolean (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/style/combinable_loops.rb', line 88



def collection_looping_method?(node)
  method_name = node.method_name
  method_name.start_with?('each') || method_name.end_with?('_each')
end


  








  

    #combine_with_left_sibling(corrector, node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/combinable_loops.rb', line 105



def combine_with_left_sibling(corrector, node)
  corrector.remove(node.left_sibling.body.source_range.end.join(node.left_sibling.loc.end))
  corrector.remove(node.source_range.begin.join(node.body.source_range.begin))

  correct_end_of_block(corrector, node)
end


  








  

    #correct_end_of_block(corrector, node)   (private)
  

  [ GitHub ]


  

  


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



def correct_end_of_block(corrector, node)
  return unless node.left_sibling.respond_to?(:braces?)
  return if node.right_sibling&.block_type? || node.right_sibling&.numblock_type?

  end_of_block = node.left_sibling.braces? ? '}' : ' end'
  corrector.remove(node.loc.end)
  corrector.insert_before(node.source_range.end, end_of_block)
end


  








  

    #on_block(node)  
    Also known as: #on_numblock
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/combinable_loops.rb', line 64



def on_block(node)
  return unless node.parent&.begin_type?
  return unless collection_looping_method?(node)
  return unless same_collection_looping_block?(node, node.left_sibling)
  return unless node.body && node.left_sibling.body

  add_offense(node) do |corrector|
    combine_with_left_sibling(corrector, node)
  end
end


  








  

    #on_for(node)  
  

  [ GitHub ]


  

  


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



def on_for(node)
  return unless node.parent&.begin_type?
  return unless same_collection_looping_for?(node, node.left_sibling)

  add_offense(node) do |corrector|
    combine_with_left_sibling(corrector, node)
  end
end


  








  

    #on_numblock(node)  
  



  

    


Alias for #on_block.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/combinable_loops.rb', line 75



alias on_numblock on_block


  








  

    #same_collection_looping_block?(node, sibling)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/combinable_loops.rb', line 93



def same_collection_looping_block?(node, sibling)
  return false if sibling.nil? || (!sibling.block_type? && !sibling.numblock_type?)

  sibling.method?(node.method_name) &&
    sibling.receiver == node.receiver &&
    sibling.send_node.arguments == node.send_node.arguments
end


  








  

    #same_collection_looping_for?(node, sibling)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/combinable_loops.rb', line 101



def same_collection_looping_for?(node, sibling)
  sibling&.for_type? && node.collection == sibling.collection
end