Class: RuboCop::Cop::Lint::StructNewOverride

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/lint/struct_new_override.rb

Overview

This cop checks unexpected overrides of the `Struct` built-in methods via `Struct.new`.

Examples:

# bad
Bad = Struct.new(:members, :clone, :count)
b = Bad.new([], true, 1)
b.members #=> [] (overriding `Struct#members`)
b.clone #=> true (overriding `Object#clone`)
b.count #=> 1 (overriding `Enumerable#count`)

# good
Good = Struct.new(:id, :name)
g = Good.new(1, "foo")
g.members #=> [:id, :name]
g.clone #=> #<struct Good id=1, name="foo">
g.count #=> 2

Constant Summary collapse

MSG =
'`%<member_name>s` member overrides `Struct#%<method_name>s`' \
' and it may be unexpected.'
RESTRICT_ON_SEND =
%i[new].freeze
STRUCT_METHOD_NAMES =
Struct.instance_methods
STRUCT_MEMBER_NAME_TYPES =
%i[sym str].freeze

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

#on_send(node) ⇒ Object


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# File 'lib/rubocop/cop/lint/struct_new_override.rb', line 38

def on_send(node)
  return unless struct_new(node) do
    node.arguments.each_with_index do |arg, index|
      # Ignore if the first argument is a class name
      next if index.zero? && arg.str_type?

      # Ignore if the argument is not a member name
      next unless STRUCT_MEMBER_NAME_TYPES.include?(arg.type)

      member_name = arg.value

      next unless STRUCT_METHOD_NAMES.include?(member_name.to_sym)

      message = format(MSG, member_name: member_name.inspect, method_name: member_name.to_s)
      add_offense(arg, message: message)
    end
  end
end

#struct_new(node) ⇒ Object


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# File 'lib/rubocop/cop/lint/struct_new_override.rb', line 33

def_node_matcher :struct_new, <<~PATTERN
  (send
    (const ${nil? cbase} :Struct) :new ...)
PATTERN