Class: RuboCop::Cop::Lint::EachWithObjectArgument

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

Overview

Checks if each_with_object is called with an immutable argument. Since the argument is the object that the given block shall make calls on to build something based on the enumerable that each_with_object iterates over, an immutable argument makes no sense. It’s definitely a bug.

Examples:


# bad
sum = numbers.each_with_object(0) { |e, a| a += e }

# good
num = 0
sum = numbers.each_with_object(num) { |e, a| a += e }

Constant Summary collapse

MSG = 
'The argument to each_with_object cannot be immutable.'
RESTRICT_ON_SEND = 
%i[each_with_object].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #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, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, 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

#each_with_object?(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/each_with_object_argument.rb', line 25

def_node_matcher :each_with_object?, <<~PATTERN
  (call _ :each_with_object $_)
PATTERN

#on_send(node) ⇒ Object Also known as: on_csend 



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# File 'lib/rubocop/cop/lint/each_with_object_argument.rb', line 29

def on_send(node)
  each_with_object?(node) do |arg|
    return unless arg.immutable_literal?

    add_offense(node)
  end
end