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

This cop 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.

This cop is marked as unsafe, because auto-correction can change the return type of the expression. An offending expression that previously could return `nil` will be auto-corrected to never return `nil`.

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)

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

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

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, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

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

add_parentheses, args_begin, args_end, begins_its_line?, comment_line?, comment_lines?, double_quotes_required?, escape_string, first_part_of_call_chain, indent, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, hidden_dir?, hidden_file?, hidden_file_in_not_hidden_dir?, match_path?, maybe_hidden_file?, relative_path, smart_path

Constructor Details

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

Instance Method Details

#on_csend(node) ⇒ Object


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# File 'lib/rubocop/cop/lint/redundant_safe_navigation.rb', line 50

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) do |corrector|
    corrector.replace(node.loc.dot, '.')
  end
end