Class: RuboCop::Cop::Style::ZeroLengthPredicate

Inherits:

Base

• Object
• Base
• RuboCop::Cop::Style::ZeroLengthPredicate

Extended by:

AutoCorrector

Defined in:

lib/rubocop/cop/style/zero_length_predicate.rb

Overview

Checks for numeric comparisons that can be replaced by a predicate method, such as receiver.length == 0, receiver.length > 0, and receiver.length != 0, receiver.length < 1 and receiver.size == 0 that can be replaced by receiver.empty? and !receiver.empty?.

Note	File, Tempfile, and StringIO do not have empty? so allow size == 0 and size.zero?.

Examples:

# bad
[1, 2, 3].length == 0
0 == "foobar".length
array.length < 1
{a: 1, b: 2}.length != 0
string.length > 0
hash.size > 0

# good
[1, 2, 3].empty?
"foobar".empty?
array.empty?
!{a: 1, b: 2}.empty?
!string.empty?
!hash.empty?

Cop Safety Information:

• This cop is unsafe because it cannot be guaranteed that the receiver has an empty? method that is defined in terms of length. If there is a non-standard class that redefines length or empty?, the cop may register a false positive.

Constant Summary

ZERO_MSG =

'Use `empty?` instead of `%<current>s`.'

NONZERO_MSG =

'Use `!empty?` instead of `%<current>s`.'

RESTRICT_ON_SEND =

%i[size length].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary

• #on_send(node) ⇒ Object

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #begin_investigation, 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, #inspect, 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?, #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

# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 45

def on_send(node)
  check_zero_length_predicate(node)
  check_zero_length_comparison(node)
  check_nonzero_length_comparison(node)
end