Class: RuboCop::Cop::Style::RedundantFetchBlock

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
FrozenStringLiteral, RangeHelp
Defined in:
lib/rubocop/cop/style/redundant_fetch_block.rb

Overview

Identifies places where ‘fetch(key) { value }` can be replaced by `fetch(key, value)`.

In such cases ‘fetch(key, value)` method is faster than `fetch(key) { value }`.

NOTE: The block string ‘’value’‘ in `hash.fetch(:key) { ’value’ }‘ is detected when frozen string literal magic comment is enabled (i.e. `# frozen_string_literal: true`), but not when disabled.

Examples:

SafeForConstants: false (default)

# bad
hash.fetch(:key) { 5 }
hash.fetch(:key) { true }
hash.fetch(:key) { nil }
array.fetch(5) { :value }
ENV.fetch(:key) { 'value' }

# good
hash.fetch(:key, 5)
hash.fetch(:key, true)
hash.fetch(:key, nil)
array.fetch(5, :value)
ENV.fetch(:key, 'value')

SafeForConstants: true

# bad
ENV.fetch(:key) { VALUE }

# good
ENV.fetch(:key, VALUE)

Constant Summary collapse

MSG = 
'Use `%<good>s` instead of `%<bad>s`.'

Constants included from FrozenStringLiteral

FrozenStringLiteral::FROZEN_STRING_LITERAL, FrozenStringLiteral::FROZEN_STRING_LITERAL_ENABLED

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods included from FrozenStringLiteral

frozen_string_literal_comment_exists?

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_block(node) ⇒ Object

rubocop:disable InternalAffairs/NumblockHandler



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# File 'lib/rubocop/cop/style/redundant_fetch_block.rb', line 55

def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler
  redundant_fetch_block_candidate?(node) do |send, body|
    return if should_not_check?(send, body)

    range = fetch_range(send, node)
    good = build_good_method(send, body)
    bad = build_bad_method(send, body)

    add_offense(range, message: format(MSG, good: good, bad: bad)) do |corrector|
      _, _, key = send.children
      default_value = body ? body.source : 'nil'

      corrector.replace(range, "fetch(#{key.source}, #{default_value})")
    end
  end
end

#redundant_fetch_block_candidate?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_fetch_block.rb', line 48

def_node_matcher :redundant_fetch_block_candidate?, <<~PATTERN
  (block
    $(call _ :fetch _)
    (args)
    ${nil? #basic_literal? #const_type?})
PATTERN