Class: RuboCop::Cop::Style::UnpackFirst

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector, TargetRubyVersion
Defined in:
lib/rubocop/cop/style/unpack_first.rb

Overview

Checks for accessing the first element of ‘String#unpack` which can be replaced with the shorter method `unpack1`.

Examples:


# bad
'foo'.unpack('h*').first
'foo'.unpack('h*')[0]
'foo'.unpack('h*').slice(0)
'foo'.unpack('h*').at(0)

# good
'foo'.unpack1('h*')

Constant Summary collapse

MSG = 
'Use `unpack1(%<format>s)` instead of `%<current>s`.'
RESTRICT_ON_SEND = 
%i[first [] slice at].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods included from TargetRubyVersion

minimum_target_ruby_version, required_minimum_ruby_version, support_target_ruby_version?

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

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



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# File 'lib/rubocop/cop/style/unpack_first.rb', line 37

def on_send(node)
  unpack_and_first_element?(node) do |unpack_call, unpack_arg|
    first_element_range = first_element_range(node, unpack_call)
    offense_range = unpack_call.loc.selector.join(node.source_range.end)
    message = format(MSG, format: unpack_arg.source, current: offense_range.source)

    add_offense(offense_range, message: message) do |corrector|
      corrector.remove(first_element_range)
      corrector.replace(unpack_call.loc.selector, 'unpack1')
    end
  end
end

#unpack_and_first_element?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/unpack_first.rb', line 30

def_node_matcher :unpack_and_first_element?, <<~PATTERN
  {
    (call $(call (...) :unpack $(...)) :first)
    (call $(call (...) :unpack $(...)) {:[] :slice :at} (int 0))
  }
PATTERN