Class: RuboCop::Cop::Style::ComparableClamp

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

Overview

Enforces the use of Comparable#clamp instead of comparison by minimum and maximum.

This cop supports autocorrection for if/elsif/else bad style only. Because ArgumentError occurs if the minimum and maximum of clamp arguments are reversed. When these are variables, it is not possible to determine which is the minimum and maximum:

[1, [2, 3].max].min # => 1
1.clamp(3, 1)       # => min argument must be smaller than max argument (ArgumentError)

Examples:


# bad
[[x, low].max, high].min

# bad
if x < low
  low
elsif high < x
  high
else
  x
end

# good
x.clamp(low, high)

Constant Summary collapse

MSG = 
'Use `%<prefer>s` instead of `if/elsif/else`.'
MSG_MIN_MAX = 
'Use `Comparable#clamp` instead.'
RESTRICT_ON_SEND = 
%i[min max].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, 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

#array_min_max?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 61

def_node_matcher :array_min_max?, <<~PATTERN
  {
    (send
      (array
        (send (array _ _) :max) _) :min)
    (send
      (array
        _ (send (array _ _) :max)) :min)
    (send
      (array
        (send (array _ _) :min) _) :max)
    (send
      (array
        _ (send (array _ _) :min)) :max)
  }
PATTERN

#if_elsif_else_condition?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 47

def_node_matcher :if_elsif_else_condition?, <<~PATTERN
  {
    (if (send _x :< _min) _min (if (send _max :< _x) _max _x))
    (if (send _min :> _x) _min (if (send _max :< _x) _max _x))
    (if (send _x :< _min) _min (if (send _x :> _max) _max _x))
    (if (send _min :> _x) _min (if (send _x :> _max) _max _x))
    (if (send _max :< _x) _max (if (send _x :< _min) _min _x))
    (if (send _x :> _max) _max (if (send _x :< _min) _min _x))
    (if (send _max :< _x) _max (if (send _min :> _x) _min _x))
    (if (send _x :> _max) _max (if (send _min :> _x) _min _x))
  }
PATTERN

#on_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 78

def on_if(node)
  return unless if_elsif_else_condition?(node)

  if_body, elsif_body, else_body = *node.branches

  else_body_source = else_body.source

  if min_condition?(node.condition, else_body_source)
    min = if_body.source
    max = elsif_body.source
  else
    min = elsif_body.source
    max = if_body.source
  end

  prefer = "#{else_body_source}.clamp(#{min}, #{max})"

  add_offense(node, message: format(MSG, prefer: prefer)) do |corrector|
    autocorrect(corrector, node, prefer)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 100

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

  add_offense(node, message: MSG_MIN_MAX)
end