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

Inherits:
Base
  • Object
show all
Includes:
NilMethods
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 collapse

MSG = 
'Do not chain ordinary method call after safe navigation operator.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #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, 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?, #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

#bad_method?(node) ⇒ Object 


32
33
34
35
36
37
 
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 32

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

#on_send(node) ⇒ Object 


39
40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/rubocop/cop/lint/safe_navigation_chain.rb', line 39

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

    method_chain = method_chain(node)
    location =
      Parser::Source::Range.new(node.source_range.source_buffer,
                                safe_nav.source_range.end_pos,
                                method_chain.source_range.end_pos)
    add_offense(location)
  end
end