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Class: RuboCop::Cop::Lint::RedundantRequireStatement

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/lint/redundant_require_statement.rb

Overview

Checks for unnecessary require statement.

The following features are unnecessary require statement because they are already loaded. e.g. Ruby 2.2:

ruby -ve 'p $LOADED_FEATURES.reject { |feature| %r|/| =~ feature }'
ruby 2.2p477 (2017-09-14 revision 59906) [x86_64-darwin13]
["enumerator.so", "rational.so", "complex.so", "thread.rb"]

Below are the features that each TargetRubyVersion targets.

  • 2.0+ …​ enumerator

  • 2.1+ …​ thread

  • 2.2+ …​ Add rational and complex above

  • 2.5+ …​ Add pp above

  • 2.7+ …​ Add ruby2_keywords above

  • 3.1+ …​ Add fiber above

  • 3.2+ …​ set

This cop target those features.

Examples:

# bad
require 'unloaded_feature'
require 'thread'

# good
require 'unloaded_feature'

Cop Safety Information:

  • This cop’s autocorrection is unsafe because if require 'pp' is removed from one file, NameError can be encountered when another file uses PP.pp.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::RangeHelp - Included

BYTE_ORDER_MARK, NOT_GIVEN

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.

.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.

.badge

Naming.

.callbacks_needed, .cop_name, .department,
.documentation_url

Returns an url to view this cops documentation online.

.exclude_from_registry

Call for abstract Cop classes.

.inherited,
.joining_forces

Override and return the Force class(es) you need to join.

.match?

Returns true if the cop name or the cop namespace matches any of the given names.

.new,
.requires_gem

Register a version requirement for the given gem name.

.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.

transform

Instance Attribute Summary

Instance Method Summary

::RuboCop::Cop::RangeHelp - Included

#add_range, #column_offset_between,
#contents_range

A range containing only the contents of a literal with delimiters (e.g.

#directions,
#effective_column

Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value.

#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.

#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.

#begin_investigation

Called before any investigation.

#callbacks_needed,
#cop_config

Configuration Helpers.

#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:

#inspect,
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.

#name

Alias for Base#cop_name.

#offenses,
#on_investigation_end

Called after all on_…​

#on_new_investigation

Called before all on_…​

#on_other_file

Called instead of all on_…​

#parse

There should be very limited reasons for a Cop to do it’s own parsing.

#parser_engine,
#ready

Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.

#complete_investigation

Called to complete an investigation.

#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:

#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.

#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Attribute Details

#need_to_require_pp?Boolean (readonly, private)

Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/redundant_require_statement.rb', line 91

def need_to_require_pp?
  processed_source.ast.each_descendant(:send).any? do |node|
    pp_const?(node.receiver) || PRETTY_PRINT_METHODS.include?(node.method_name)
  end
end

Instance Method Details

#on_send(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/redundant_require_statement.rb', line 61

def on_send(node)
  return unless redundant_require_statement?(node)

  add_offense(node) do |corrector|
    if node.parent.respond_to?(:modifier_form?) && node.parent.modifier_form?
      corrector.insert_after(node.parent, "\nend")

      range = range_with_surrounding_space(node.source_range, side: :right)
    else
      range = range_by_whole_lines(node.source_range, include_final_newline: true)
    end

    corrector.remove(range)
  end
end

#pp_const?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/redundant_require_statement.rb', line 57

def_node_matcher :pp_const?, <<~PATTERN
  (const {nil? cbase} :PP)
PATTERN

#redundant_feature?(feature_name) ⇒ Boolean (private)

Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/redundant_require_statement.rb', line 80

def redundant_feature?(feature_name)
  feature_name == 'enumerator' ||
    (target_ruby_version >= 2.1 && feature_name == 'thread') ||
    (target_ruby_version >= 2.2 && RUBY_22_LOADED_FEATURES.include?(feature_name)) ||
    (target_ruby_version >= 2.5 && feature_name == 'pp' && !need_to_require_pp?) ||
    (target_ruby_version >= 2.7 && feature_name == 'ruby2_keywords') ||
    (target_ruby_version >= 3.1 && feature_name == 'fiber') ||
    (target_ruby_version >= 3.2 && feature_name == 'set')
end

#redundant_require_statement?(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/redundant_require_statement.rb', line 51

def_node_matcher :redundant_require_statement?, <<~PATTERN
  (send nil? :require
    (str #redundant_feature?))
PATTERN