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Class: RuboCop::Cop::Style::IfUnlessModifier

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::CommentsHelp, ::RuboCop::Cop::RangeHelp, ::RuboCop::Cop::AllowedPattern, ::RuboCop::Cop::StatementModifier, ::RuboCop::Cop::LineLengthHelp, ::RuboCop::Cop::Alignment, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/if_unless_modifier.rb

Overview

Checks for if and unless statements that would fit on one line if written as modifier if/unless. The cop also checks for modifier if/unless lines that exceed the maximum line length.

The maximum line length is configured in the Layout/LineLength cop. The tab size is configured in the IndentationWidth of the Layout/IndentationStyle cop.

One-line pattern matching is always allowed. To ensure that there are few cases where the match variable is not used, and to prevent oversights. The variable x becomes undefined and raises NameError when the following example is changed to the modifier form:

if [42] in [x]
  x # {x} is undefined when using modifier form.
end
Note
 It is allowed when defined? argument has an undefined value, because using the modifier form causes the following incompatibility: 
unless defined?(undefined_foo)
  undefined_foo = 'default_value'
end
undefined_foo # => 'default_value'

undefined_bar = 'default_value' unless defined?(undefined_bar)
undefined_bar # => nil

Examples:

# bad
if condition
  do_stuff(bar)
end

unless qux.empty?
  Foo.do_something
end

do_something_with_a_long_name(arg) if long_condition_that_prevents_code_fit_on_single_line

# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?

if long_condition_that_prevents_code_fit_on_single_line
  do_something_with_a_long_name(arg)
end

if short_condition # a long comment that makes it too long if it were just a single line
  do_something
end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::Alignment - Included

SPACE

::RuboCop::Cop::RangeHelp - Included

BYTE_ORDER_MARK, NOT_GIVEN

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.

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 a 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

::RuboCop::Cop::AllowedPattern - Included

#ignored_line?, #matches_ignored_pattern?

::RuboCop::Cop::LineLengthHelp - Included

#allow_uri?, #ignore_cop_directives?

::RuboCop::Cop::Alignment - Included

#column_delta

::RuboCop::Cop::Base - Inherited

#active_support_extensions_enabled?, #always_autocorrect?, #config, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #processed_source, #string_literals_frozen_by_default?, #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::CommentsHelp - Included

#comments_contain_disables?, #comments_in_range, #contains_comments?, #source_range_with_comment, #begin_pos_with_comment, #buffer, #end_position_for,
#find_end_line

Returns the end line of a node, which might be a comment and not part of the AST End line is considered either the line at which another node starts, or the line at which the parent node ends.
#start_line_position

::RuboCop::Cop::RangeHelp - Included

#add_range, #column_offset_between,
#contents_range

A range containing only the contents of a literal with delimiters (e.g.
#directions,
#effective_column

Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value.
#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range

::RuboCop::Cop::AllowedPattern - Included

#allowed_line?, #allowed_patterns, #cop_config_deprecated_methods_values, #cop_config_patterns_values, #matches_allowed_pattern?

::RuboCop::Cop::StatementModifier - Included

#code_after, #comment_disables_cop?, #first_line_comment, #if_body_source, #length_in_modifier_form, #max_line_length, #method_source, #modifier_fits_on_single_line?, #non_eligible_body?, #non_eligible_condition?, #non_eligible_node?, #parenthesize?, #single_line_as_modifier?, #to_modifier_form

::RuboCop::Cop::LineLengthHelp - Included

#allowed_uri_position?, #directive_on_source_line?, #extend_uri_end_position, #find_excessive_uri_range, #indentation_difference, #line_length, #line_length_without_directive, #match_uris, #tab_indentation_width, #uri_regexp, #valid_uri?

::RuboCop::Cop::Alignment - Included

#check_alignment, #configured_indentation_width, #display_column, #each_bad_alignment, #end_of_line_comment, #indentation, #offset, #register_offense, #within?

::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

#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, #range_overlaps_offense?, #string_continuation, #string_continuation?, #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

Class Method Details

.autocorrect_incompatible_with

[ GitHub ] 

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 76



def self.autocorrect_incompatible_with
  [Style::SoleNestedConditional]
end


  







Instance Method Details



  

    #allowed_patterns   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 171



def allowed_patterns
  line_length_config = config.for_cop('Layout/LineLength')
  line_length_config['AllowedPatterns'] || line_length_config['IgnoredPatterns'] || []
end


  








  

    #another_statement_on_same_line?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 231



def another_statement_on_same_line?(node)
  line_no = node.source_range.last_line

  # traverse the AST upwards until we find a 'begin' node
  # we want to look at the following child and see if it is on the
  #   same line as this 'if' node
  while node && !node.begin_type?
    index = node.sibling_index
    node  = node.parent
  end

  node && (sibling = node.children[index + 1]) && sibling.source_range.first_line == line_no
end


  








  

    #autocorrect(corrector, node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 132



def autocorrect(corrector, node)
  replacement = if node.modifier_form?
                  replacement_for_modifier_form(corrector, node)
                else
                  to_modifier_form(node)
                end
  corrector.replace(node, replacement)
end


  








  

    #comment_on_node_line(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 285



def comment_on_node_line(node)
  processed_source.comments.find { |c| same_line?(c, node) }
end


  








  

    #defined_argument_is_undefined?(if_node, defined_node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 104



def defined_argument_is_undefined?(if_node, defined_node)
  defined_argument = defined_node.first_argument
  return false unless defined_argument.lvar_type? || defined_argument.send_type?

  if_node.left_siblings.none? do |sibling|
    sibling.respond_to?(:lvasgn_type?) && sibling.lvasgn_type? &&
      sibling.name == defined_argument.node_parts[0]
  end
end


  








  

    #defined_nodes(condition)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 96



def defined_nodes(condition)
  if condition.defined_type?
    [condition]
  else
    condition.each_descendant.select(&:defined_type?)
  end
end


  








  

    #extract_heredoc_from(last_argument)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 272



def extract_heredoc_from(last_argument)
  heredoc_body = last_argument.loc.heredoc_body
  heredoc_end = last_argument.loc.heredoc_end

  [heredoc_body, heredoc_end]
end


  








  

    #line_length_enabled_at_line?(line)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 215



def line_length_enabled_at_line?(line)
  processed_source.comment_config.cop_enabled_at_line?('Layout/LineLength', line)
end


  








  

    #message(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 124



def message(node)
  if single_line_as_modifier?(node) && !named_capture_in_condition?(node)
    MSG_USE_MODIFIER
  elsif too_long_due_to_modifier?(node)
    MSG_USE_NORMAL
  end
end


  








  

    #named_capture_in_condition?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 219



def named_capture_in_condition?(node)
  node.condition.match_with_lvasgn_type?
end


  








  

    #non_eligible_node?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 223



def non_eligible_node?(node)
  non_simple_if_unless?(node) || node.chained? || node.nested_conditional? || super
end


  








  

    #non_simple_if_unless?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 227



def non_simple_if_unless?(node)
  node.ternary? || node.elsif? || node.else?
end


  








  

    #on_if(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 80



def on_if(node)
  condition = node.condition
  return if defined_nodes(condition).any? { |n| defined_argument_is_undefined?(node, n) } ||
            pattern_matching_nodes(condition).any?
  return unless (msg = message(node))

  add_offense(node.loc.keyword, message: format(msg, keyword: node.keyword)) do |corrector|
    next if part_of_ignored_node?(node)

    autocorrect(corrector, node)
    ignore_node(node)
  end
end


  








  

    #pattern_matching_nodes(condition)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 114



def pattern_matching_nodes(condition)
  if condition.match_pattern_type? || condition.match_pattern_p_type?
    [condition]
  else
    condition.each_descendant.select do |node|
      node.match_pattern_type? || node.match_pattern_p_type?
    end
  end
end


  








  

    #remove_comment(corrector, _node, comment)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 289



def remove_comment(corrector, _node, comment)
  corrector.remove(range_with_surrounding_space(range: comment.source_range, side: :left))
end


  








  

    #remove_heredoc(corrector, heredoc)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 279



def remove_heredoc(corrector, heredoc)
  heredoc.each do |range|
    corrector.remove(range_by_whole_lines(range, include_final_newline: true))
  end
end


  








  

    #replacement_for_modifier_form(corrector, node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 141



def replacement_for_modifier_form(corrector, node) # rubocop:disable Metrics/AbcSize
  comment = comment_on_node_line(node)
  if comment && too_long_due_to_comment_after_modifier?(node, comment)
    remove_comment(corrector, node, comment)

    return to_modifier_form_with_move_comment(node, indent(node), comment)
  end

  last_argument = node.if_branch.last_argument if node.if_branch.send_type?
  if last_argument.respond_to?(:heredoc?) && last_argument.heredoc?
    heredoc = extract_heredoc_from(last_argument)
    remove_heredoc(corrector, heredoc)

    return to_normal_form_with_heredoc(node, indent(node), heredoc)
  end

  to_normal_form(node, indent(node))
end


  








  

    #to_modifier_form_with_move_comment(node, indentation, comment)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 265



def to_modifier_form_with_move_comment(node, indentation, comment)
  <<~RUBY.chomp
    #{comment.source}
    #{indentation}#{node.body.source} #{node.keyword} #{node.condition.source}
  RUBY
end


  








  

    #to_normal_form(node, indentation)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 245



def to_normal_form(node, indentation)
  <<~RUBY.chomp
    #{node.keyword} #{node.condition.source}
    #{indentation}  #{node.body.source}
    #{indentation}end
  RUBY
end


  








  

    #to_normal_form_with_heredoc(node, indentation, heredoc)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 253



def to_normal_form_with_heredoc(node, indentation, heredoc)
  heredoc_body, heredoc_end = heredoc

  <<~RUBY.chomp
    #{node.keyword} #{node.condition.source}
    #{indentation}  #{node.body.source}
    #{indentation}  #{heredoc_body.source.chomp}
    #{indentation}  #{heredoc_end.source.chomp}
    #{indentation}end
  RUBY
end


  








  

    #too_long_due_to_comment_after_modifier?(node, comment)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 165



def too_long_due_to_comment_after_modifier?(node, comment)
  source_length = processed_source.lines[node.first_line - 1].length
  source_length >= max_line_length &&
    source_length - comment.source_range.length <= max_line_length
end


  








  

    #too_long_due_to_modifier?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 160



def too_long_due_to_modifier?(node)
  node.modifier_form? && too_long_single_line?(node) &&
    !another_statement_on_same_line?(node)
end


  








  

    #too_long_line_based_on_allow_uri?(line)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 206



def too_long_line_based_on_allow_uri?(line)
  if allow_uri?
    uri_range = find_excessive_uri_range(line)
    return false if uri_range && allowed_uri_position?(line, uri_range)
  end

  true
end


  








  

    #too_long_line_based_on_config?(range, line)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 189



def too_long_line_based_on_config?(range, line)
  return false if matches_allowed_pattern?(line)

  too_long = too_long_line_based_on_ignore_cop_directives?(range, line)
  return too_long unless too_long == :undetermined

  too_long_line_based_on_allow_uri?(line)
end


  








  

    #too_long_line_based_on_ignore_cop_directives?(range, line)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 198



def too_long_line_based_on_ignore_cop_directives?(range, line)
  if ignore_cop_directives? && directive_on_source_line?(range.line - 1)
    return line_length_without_directive(line) > max_line_length
  end

  :undetermined
end


  








  

    #too_long_single_line?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/if_unless_modifier.rb', line 176



def too_long_single_line?(node)
  return false unless max_line_length

  range = node.source_range
  return false unless range.single_line?
  return false unless line_length_enabled_at_line?(range.first_line)

  line = range.source_line
  return false if line_length(line) <= max_line_length

  too_long_line_based_on_config?(range, line)
end