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Class: RuboCop::Cop::Metrics::PerceivedComplexity

Overview

Tries to produce a complexity score that’s a measure of the complexity the reader experiences when looking at a method. For that reason it considers when nodes as something that doesn’t add as much complexity as an if or a &&. Except if it’s one of those special case/when constructs where there’s no expression after case. Then the cop treats it as an if/elsif/elsif…​ and lets all the when nodes count. In contrast to the CyclomaticComplexity cop, this cop considers else nodes as adding complexity.

Examples:

def my_method                   # 1
  if cond                       # 1
    case var                    # 2 (0.8 + 4 * 0.2, rounded)
    when 1 then func_one
    when 2 then func_two
    when 3 then func_three
    when 4..10 then func_other
    end
  else                          # 1
    do_something until a && b   # 2
  end                           # ===
end                             # 7 complexity points

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Utils::IteratingBlock - Included

KNOWN_ITERATING_METHODS

CyclomaticComplexity - Inherited

COUNTED_NODES, MSG

Class Attribute Summary

::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

CyclomaticComplexity - Inherited

Utils::IteratingBlock - Included

#block_method_name

Returns the name of the method called with a block if node is a block node, or a block-pass node.

#iterating_block?

Returns nil if node is neither a block node or a block-pass node.

#iterating_method?

Returns true iff name is a known iterating type (e.g.

::RuboCop::Cop::MethodComplexity - Included

Utils::RepeatedCsendDiscount - Included

::RuboCop::Cop::AllowedPattern - Included

::RuboCop::Cop::AllowedMethods - 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

#complexity_score_for(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/metrics/perceived_complexity.rb', line 36

def complexity_score_for(node)
  case node.type
  when :case
    # If cond is nil, that means each when has an expression that
    # evaluates to true or false. It's just an alternative to
    # if/elsif/elsif... so the when nodes count.
    nb_branches = node.when_branches.length + (node.else_branch ? 1 : 0)
    if node.condition.nil?
      nb_branches
    else
      # Otherwise, the case node gets 0.8 complexity points and each
      # when gets 0.2.
      ((nb_branches * 0.2) + 0.8).round
    end
  when :if
    node.else? && !node.elsif? ? 2 : 1
  else
    super
  end
end