Class: RuboCop::Cop::Lint::NumberConversion

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
AllowedMethods, AllowedPattern, IgnoredNode
Defined in:
lib/rubocop/cop/lint/number_conversion.rb

Overview

Warns the usage of unsafe number conversions. Unsafe number conversion can cause unexpected error if auto type conversion fails. Cop prefer parsing with number class instead.

Conversion with Integer, Float, etc. will raise an ArgumentError if given input that is not numeric (eg. an empty string), whereas to_i, etc. will try to convert regardless of input (''.to_i ⇒ 0). As such, this cop is disabled by default because it’s not necessarily always correct to raise if a value is not numeric.

Note
 Some values cannot be converted properly using one of the Kernel method (for instance, Time and DateTime values are allowed by this cop by default). Similarly, Rails' duration methods do not work well with Integer() and can be allowed with AllowedMethods. By default, there are no methods to allowed.

Examples:


# bad

'10'.to_i
'10.2'.to_f
'10'.to_c
'1/3'.to_r
['1', '2', '3'].map(&:to_i)
foo.try(:to_f)
bar.send(:to_c)

# good

Integer('10', 10)
Float('10.2')
Complex('10')
Rational('1/3')
['1', '2', '3'].map { |i| Integer(i, 10) }
foo.try { |i| Float(i) }
bar.send { |i| Complex(i) }

AllowedMethods: [] (default)


# bad
10.minutes.to_i

AllowedMethods: [minutes]


# good
10.minutes.to_i

AllowedPatterns: [] (default)


# bad
10.minutes.to_i

AllowedPatterns: ['min*']


# good
10.minutes.to_i

IgnoredClasses: [Time, DateTime] (default)


# good
Time.now.to_datetime.to_i

Cop Safety Information:

  • Autocorrection is unsafe because it is not guaranteed that the replacement Kernel methods are able to properly handle the input if it is not a standard class.

Constant Summary collapse

CONVERSION_METHOD_CLASS_MAPPING = 
{
  to_i: "#{Integer.name}(%<number_object>s, 10)",
  to_f: "#{Float.name}(%<number_object>s)",
  to_c: "#{Complex.name}(%<number_object>s)",
  to_r: "#{Rational.name}(%<number_object>s)"
}.freeze
MSG = 
'Replace unsafe number conversion with number ' \
'class parsing, instead of using ' \
'`%<current>s`, use stricter ' \
'`%<corrected_method>s`.'
CONVERSION_METHODS = 
%i[Integer Float Complex Rational to_i to_f to_c to_r].freeze
METHODS = 
CONVERSION_METHOD_CLASS_MAPPING.keys.map(&:inspect).join(' ')

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 IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

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 Util

silence_warnings

Constructor Details

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

Instance Method Details

#on_send(node) ⇒ Object 



103
104
105
106
 
# File 'lib/rubocop/cop/lint/number_conversion.rb', line 103

def on_send(node)
  handle_conversion_method(node)
  handle_as_symbol(node)
end

#to_method(node) ⇒ Object 



93
94
95
 
# File 'lib/rubocop/cop/lint/number_conversion.rb', line 93

def_node_matcher :to_method, <<~PATTERN
  (send $_ ${#{METHODS}})
PATTERN

#to_method_symbol(node) ⇒ Object 



98
99
100
101
 
# File 'lib/rubocop/cop/lint/number_conversion.rb', line 98

def_node_matcher :to_method_symbol, <<~PATTERN
  {(send _ $_ ${(sym ${#{METHODS}})} ...)
   (send _ $_ ${(block_pass (sym ${#{METHODS}}))} ...)}
PATTERN