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Class: RuboCop::Cop::Style::InfiniteLoop

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/infinite_loop.rb

Overview

Use Kernel#loop for infinite loops.

Examples:

# bad
while true
  work
end

# good
loop do
  work
end

Cop Safety Information:

  • This cop is unsafe as the rule should not necessarily apply if the loop body might raise a StopIteration exception; contrary to other infinite loops, Kernel#loop silently rescues that and returns nil.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::Alignment - Included

SPACE

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::Alignment - Included

::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

Class Method Details

.joining_forces

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 31

def self.joining_forces
  VariableForce
end

Instance Method Details

#after_leaving_scope(scope, _variable_table)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 35

def after_leaving_scope(scope, _variable_table)
  @variables ||= []
  @variables.concat(scope.variables.values)
end

#assigned_before_loop?(var, range) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 84

def assigned_before_loop?(var, range)
  b = range.begin_pos
  var.assignments.any? { |a| a.node.source_range.end_pos < b }
end

#assigned_inside_loop?(var, range) ⇒ Boolean (private)

[ GitHub ]

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

def assigned_inside_loop?(var, range)
  var.assignments.any? { |a| range.contains?(a.node.source_range) }
end

#autocorrect(corrector, node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 70

def autocorrect(corrector, node)
  if node.while_post_type? || node.until_post_type?
    replace_begin_end_with_modifier(corrector, node)
  elsif node.modifier_form?
    replace_source(corrector, node.source_range, modifier_replacement(node))
  else
    replace_source(corrector, non_modifier_range(node), 'loop do')
  end
end

#modifier_replacement(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 103

def modifier_replacement(node)
  body = node.body
  if node.single_line?
    "loop { #{body.source} }"
  else
    indentation = body.source_range.source_line[LEADING_SPACE]

    ['loop do', body.source.gsub(/^/, indentation(node)), 'end'].join("\n#{indentation}")
  end
end

#non_modifier_range(node) (private)

[ GitHub ]

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

def non_modifier_range(node)
  start_range = node.loc.keyword.begin
  end_range = if node.do?
                node.loc.begin.end
              else
                node.condition.source_range.end
              end

  start_range.join(end_range)
end

#on_until(node) Also known as: #on_until_post

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 44

def on_until(node)
  while_or_until(node) if node.condition.falsey_literal?
end

#on_until_post(node)

Alias for #on_until.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 49

alias on_until_post on_until

#on_while(node) Also known as: #on_while_post

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 40

def on_while(node)
  while_or_until(node) if node.condition.truthy_literal?
end

#on_while_post(node)

Alias for #on_while.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 48

alias on_while_post on_while

#referenced_after_loop?(var, range) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 89

def referenced_after_loop?(var, range)
  e = range.end_pos
  var.references.any? { |r| r.node.source_range.begin_pos > e }
end

#replace_begin_end_with_modifier(corrector, node) (private)

[ GitHub ]

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

def replace_begin_end_with_modifier(corrector, node)
  corrector.replace(node.body.loc.begin, 'loop do')
  corrector.remove(node.body.loc.end.end.join(node.source_range.end))
end

#replace_source(corrector, range, replacement) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 99

def replace_source(corrector, range, replacement)
  corrector.replace(range, replacement)
end

#while_or_until(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/infinite_loop.rb', line 53

def while_or_until(node)
  range = node.source_range
  # Not every `while true` and `until false` can be turned into a
  # `loop do` without further modification. The reason is that a
  # variable that's introduced inside a while/until loop is in scope
  # outside of that loop too, but a variable that's assigned for the
  # first time inside a block cannot be accessed after the block. In
  # those more complicated cases we don't report an offense.
  return if @variables.any? do |var|
    assigned_inside_loop?(var, range) &&
    !assigned_before_loop?(var, range) &&
    referenced_after_loop?(var, range)
  end

  add_offense(node.loc.keyword) { |corrector| autocorrect(corrector, node) }
end