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Class: RuboCop::Cop::Lint::SafeNavigationChain

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/lint/safe_navigation_chain.rb

Overview

The safe navigation operator returns nil if the receiver is nil. If you chain an ordinary method call after a safe navigation operator, it raises NoMethodError. We should use a safe navigation operator after a safe navigation operator. This cop checks for the problem outlined above.

Examples:

# bad

x&.foo.bar
x&.foo + bar
x&.foo[bar]
# good

x&.foo&.bar
x&.foo || bar

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

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::TargetRubyVersion - Extended

::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::NilMethods - Included

::RuboCop::Cop::AllowedMethods - 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

Instance Method Details

#add_safe_navigation_operator(offense_range:, send_node:) ⇒ String (private)

Parameters:

  • offense_range (Parser::Source::Range)
  • send_node (RuboCop::AST::SendNode)
[ GitHub ]

  
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 62

def add_safe_navigation_operator(offense_range:, send_node:)
  source =
    if brackets?(send_node)
      format(
        '%<method_name>s(%<arguments>s)%<method_chain>s',
        arguments: send_node.arguments.map(&:source).join(', '),
        method_name: send_node.method_name,
        method_chain: send_node.source_range.end.join(send_node.source_range.end).source
      )
    else
      offense_range.source
    end
  source.prepend('.') unless source.start_with?('.')
  source.prepend('&')
end

#autocorrect(corrector, offense_range:, send_node:) (private)

Parameters:

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 81

def autocorrect(corrector, offense_range:, send_node:)
  corrector.replace(
    offense_range,
    add_safe_navigation_operator(offense_range: offense_range, send_node: send_node)
  )

  corrector.wrap(send_node, '(', ')') if require_parentheses?(send_node)
end

#bad_method?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 37

def_node_matcher :bad_method?, <<~PATTERN
  {
    (send $(csend ...) $_ ...)
    (send $({block numblock} (csend ...) ...) $_ ...)
  }
PATTERN

#brackets?(send_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 90

def brackets?(send_node)
  send_node.method?(:[]) || send_node.method?(:[]=)
end

#on_send(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 44

def on_send(node)
  bad_method?(node) do |safe_nav, method|
    return if nil_methods.include?(method) || PLUS_MINUS_METHODS.include?(node.method_name)

    begin_range = node.loc.dot || safe_nav.source_range.end
    location = begin_range.join(node.source_range.end)

    add_offense(location) do |corrector|
      autocorrect(corrector, offense_range: location, send_node: node)
    end
  end
end

#require_parentheses?(send_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 94

def require_parentheses?(send_node)
  return false unless send_node.comparison_method?
  return false unless (node = send_node.parent)

  (node.respond_to?(:logical_operator?) && node.logical_operator?) ||
    (node.respond_to?(:comparison_method?) && node.comparison_method?)
end