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

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
Instance Chain:
Inherits: RuboCop::Cop::Base
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

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::Alignment - Included

SPACE

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::TargetRubyVersion - Extended

::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::Alignment - Included

::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 Method Details

#array_min_max?(node)

[ GitHub ]

  
# 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

#autocorrect(corrector, node, prefer) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 108

def autocorrect(corrector, node, prefer)
  if node.elsif?
    corrector.insert_before(node, "else\n")
    corrector.replace(node, "#{indentation(node)}#{prefer}")
  else
    corrector.replace(node, prefer)
  end
end

#if_elsif_else_condition?(node)

[ GitHub ]

  
# 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

#min_condition?(if_condition, else_body) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/comparable_clamp.rb', line 117

def min_condition?(if_condition, else_body)
  lhs, op, rhs = *if_condition

  (lhs.source == else_body && op == :<) || (rhs.source == else_body && op == :>)
end

#on_if(node)

[ GitHub ]

  
# 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)

[ GitHub ]

  
# 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