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Class: RuboCop::Cop::Lint::EmptyBlock

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::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/lint/empty_block.rb

Overview

Checks for blocks without a body. Such empty blocks are typically an oversight or we should provide a comment to clarify what we’re aiming for.

Empty lambdas and procs are ignored by default.

Note
 For backwards compatibility, the configuration that allows/disallows empty lambdas and procs is called AllowEmptyLambdas, even though it also applies to procs.

Examples:

# bad
items.each { |item| }

# good
items.each { |item| puts item }

AllowComments: true (default)

# good
items.each do |item|
  # TODO: implement later (inner comment)
end

items.each { |item| } # TODO: implement later (inline comment)

AllowComments: false

# bad
items.each do |item|
  # TODO: implement later (inner comment)
end

items.each { |item| } # TODO: implement later (inline comment)

AllowEmptyLambdas: true (default)

# good
allow(subject).to receive(:callable).and_return(-> {})

placeholder = lambda do
end
(callable || placeholder).call

proc { }

Proc.new { }

AllowEmptyLambdas: false

# bad
allow(subject).to receive(:callable).and_return(-> {})

placeholder = lambda do
end
(callable || placeholder).call

proc { }

Proc.new { }

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::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 Attribute Details

#allow_empty_lambdas? ⇒ Boolean (readonly, private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/lint/empty_block.rb', line 83



def allow_empty_lambdas?
  cop_config['AllowEmptyLambdas']
end


  







Instance Method Details



  

    #allow_comment?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/empty_block.rb', line 76



def allow_comment?(node)
  return false unless processed_source.contains_comment?(node.source_range)

  line_comment = processed_source.comment_at_line(node.source_range.line)
  !line_comment || !comment_disables_cop?(line_comment.source)
end


  








  

    #comment_disables_cop?(comment)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/empty_block.rb', line 87



def comment_disables_cop?(comment)
  regexp_pattern = "# rubocop : (disable|todo) ([^,],)* (all|#{cop_name})"
  Regexp.new(regexp_pattern.gsub(' ', '\s*')).match?(comment)
end


  








  

    #on_block(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/empty_block.rb', line 66



def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler
  return if node.body
  return if allow_empty_lambdas? && node.lambda_or_proc?
  return if cop_config['AllowComments'] && allow_comment?(node)

  add_offense(node)
end