Class: RuboCop::Cop::Lint::RedundantSafeNavigation

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
AllowedMethods, RangeHelp
Defined in:
lib/rubocop/cop/lint/redundant_safe_navigation.rb

Overview

Checks for redundant safe navigation calls. ‘instance_of?`, `kind_of?`, `is_a?`, `eql?`, `respond_to?`, and `equal?` methods are checked by default. These are customizable with `AllowedMethods` option.

The ‘AllowedMethods` option specifies nil-safe methods, in other words, it is a method that is allowed to skip safe navigation. Note that the `AllowedMethod` option is not an option that specifies methods for which to suppress (allow) this cop’s check.

In the example below, the safe navigation operator (‘&.`) is unnecessary because `NilClass` has methods like `respond_to?` and `is_a?`.

Examples:

# bad
do_something if attrs&.respond_to?(:[])

# good
do_something if attrs.respond_to?(:[])

# bad
while node&.is_a?(BeginNode)
  node = node.parent
end

# good
while node.is_a?(BeginNode)
  node = node.parent
end

# good - without `&.` this will always return `true`
foo&.respond_to?(:to_a)

AllowedMethods: [nil_safe_method]

# bad
do_something if attrs&.nil_safe_method(:[])

# good
do_something if attrs.nil_safe_method(:[])
do_something if attrs&.not_nil_safe_method(:[])

Constant Summary collapse

MSG = 
'Redundant safe navigation detected.'
NIL_SPECIFIC_METHODS = 
(nil.methods - Object.new.methods).to_set.freeze

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #begin_investigation, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

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

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#on_csend(node) ⇒ Object 



65
66
67
68
69
70
71
 
# File 'lib/rubocop/cop/lint/redundant_safe_navigation.rb', line 65

def on_csend(node)
  return unless check?(node) && allowed_method?(node.method_name)
  return if respond_to_nil_specific_method?(node)

  range = range_between(node.loc.dot.begin_pos, node.source_range.end_pos)
  add_offense(range) { |corrector| corrector.replace(node.loc.dot, '.') }
end

#respond_to_nil_specific_method?(node) ⇒ Object 



61
62
63
 
# File 'lib/rubocop/cop/lint/redundant_safe_navigation.rb', line 61

def_node_matcher :respond_to_nil_specific_method?, <<~PATTERN
  (csend _ :respond_to? (sym %NIL_SPECIFIC_METHODS))
PATTERN