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Class: RuboCop::Cop::Lint::LiteralAsCondition

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::RangeHelp, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/lint/literal_as_condition.rb

Overview

Checks for literals used as the conditions or as operands in and/or expressions serving as the conditions of if/while/until/case-when/case-in.

Note
 Literals in case-in condition where the match variable is used in in are accepted as a pattern matching.

Examples:

# bad
if 20
  do_something
end

# bad
# We're only interested in the left hand side being a truthy literal,
# because it affects the evaluation of the &&, whereas the right hand
# side will be conditionally executed/called and can be a literal.
if true && some_var
  do_something
end

# good
if some_var
  do_something
end

# good
# When using a boolean value for an infinite loop.
while true
  break if condition
end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::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::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::RangeHelp - Included

#add_range,
#arguments_range

A range containing the first to the last argument of a method call or method definition.
#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::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_gem_version

Returns a gems locked versions (i.e.
#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, #heredoc_range, #max_line_length, #multiline_ranges, #multiline_string?,
#range_by_lines

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

Instance Method Details

#basic_literal?(node) ⇒ Boolean (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 179



def basic_literal?(node)
  if node.array_type?
    primitive_array?(node)
  else
    node.basic_literal?
  end
end


  








  

    #check_case(case_node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 211



def check_case(case_node)
  condition = case_node.condition

  return if condition.array_type? && !primitive_array?(condition)
  return if condition.dstr_type?

  handle_node(condition)
end


  








  

    #check_for_literal(node)   (private)
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 170



def check_for_literal(node)
  cond = condition(node)
  if cond.literal?
    add_offense(cond)
  else
    check_node(cond)
  end
end


  








  

    #check_node(node)   (private)
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 191



def check_node(node)
  if node.send_type? && node.prefix_bang?
    handle_node(node.receiver)
  elsif node.operator_keyword?
    node.each_child_node { |op| handle_node(op) }
  elsif node.begin_type? && node.children.one?
    handle_node(node.children.first)
  end
end


  








  

    #condition(node)   (private)
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 220



def condition(node)
  if node.send_type?
    node.receiver
  else
    node.condition
  end
end


  








  

    #correct_if_node(node, cond, result)   (private)
  



  

    


Metrics/MethodLength



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 236



def correct_if_node(node, cond, result)
  if result
    add_offense(cond) do |corrector|
      corrector.replace(node, node.if_branch.source)
    end
  elsif node.elsif_conditional?
    add_offense(cond) do |corrector|
      corrector.replace(node, "#{node.else_branch.source.sub('elsif', 'if')}\nend")
    end
  elsif node.else? || node.ternary?
    add_offense(cond) do |corrector|
      corrector.replace(node, node.else_branch.source)
    end
  else
    add_offense(cond) do |corrector|
      corrector.remove(node)
    end
  end
end


  








  

    #handle_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 201



def handle_node(node)
  if node.literal?
    return if node.parent.and_type?

    add_offense(node)
  elsif %i[send and or begin].include?(node.type)
    check_node(node)
  end
end


  








  

    #message(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 164



def message(node)
  format(MSG, literal: node.source)
end


  








  

    #on_and(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 45



def on_and(node)
  return unless node.lhs.truthy_literal?

  add_offense(node.lhs) do |corrector|
    # Don't autocorrect `'foo' && return` because having `return` as
    # the leftmost node can lead to a void value expression syntax error.
    next if node.rhs.type?(:return, :break, :next)

    corrector.replace(node, node.rhs.source)
  end
end


  








  

    #on_case(case_node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 129



def on_case(case_node)
  if case_node.condition
    check_case(case_node)
  else
    case_node.when_branches.each do |when_node|
      next unless when_node.conditions.all?(&:literal?)

      range = when_conditions_range(when_node)
      message = message(range)

      add_offense(range, message: message)
    end
  end
end


  








  

    #on_case_match(case_match_node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 144



def on_case_match(case_match_node)
  if case_match_node.condition
    return if case_match_node.descendants.any?(&:match_var_type?)

    check_case(case_match_node)
  else
    case_match_node.each_in_pattern do |in_pattern_node|
      next unless in_pattern_node.condition.literal?

      add_offense(in_pattern_node)
    end
  end
end


  








  

    #on_if(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 57



def on_if(node)
  cond = condition(node)

  if node.unless?
    correct_if_node(node, cond, true) if cond.falsey_literal?
    correct_if_node(node, cond, false) if cond.truthy_literal?
  else
    correct_if_node(node, cond, true) if cond.truthy_literal?
    correct_if_node(node, cond, false) if cond.falsey_literal?
  end
end


  








  

    #on_send(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 158



def on_send(node)
  return unless node.negation_method?

  check_for_literal(node)
end


  








  

    #on_until(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 99



def on_until(node)
  return if node.condition.source == 'false'

  if node.condition.falsey_literal?
    add_offense(node.condition) do |corrector|
      corrector.replace(node.condition, 'false')
    end
  elsif node.condition.truthy_literal?
    add_offense(node.condition) do |corrector|
      corrector.remove(node)
    end
  end
end


  








  

    #on_until_post(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 114



def on_until_post(node)
  return if node.condition.source == 'false'

  if node.condition.falsey_literal?
    add_offense(node.condition) do |corrector|
      corrector.replace(node, node.source.sub(node.condition.source, 'false'))
    end
  elsif node.condition.truthy_literal?
    add_offense(node.condition) do |corrector|
      corrector.replace(node, node.body.child_nodes.map(&:source).join("\n"))
    end
  end
end


  








  

    #on_while(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 69



def on_while(node)
  return if node.condition.source == 'true'

  if node.condition.truthy_literal?
    add_offense(node.condition) do |corrector|
      corrector.replace(node.condition, 'true')
    end
  elsif node.condition.falsey_literal?
    add_offense(node.condition) do |corrector|
      corrector.remove(node)
    end
  end
end


  








  

    #on_while_post(node)  
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 84



def on_while_post(node)
  return if node.condition.source == 'true'

  if node.condition.truthy_literal?
    add_offense(node.condition) do |corrector|
      corrector.replace(node, node.source.sub(node.condition.source, 'true'))
    end
  elsif node.condition.falsey_literal?
    add_offense(node.condition) do |corrector|
      corrector.replace(node, node.body.child_nodes.map(&:source).join("\n"))
    end
  end
end


  








  

    #primitive_array?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 187



def primitive_array?(node)
  node.children.all? { |n| basic_literal?(n) }
end


  








  

    #when_conditions_range(when_node)   (private)
  

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# File 'lib/rubocop/cop/lint/literal_as_condition.rb', line 228



def when_conditions_range(when_node)
  range_between(
    when_node.conditions.first.source_range.begin_pos,
    when_node.conditions.last.source_range.end_pos
  )
end