Class: RuboCop::Cop::Metrics::CyclomaticComplexity

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/metrics/cyclomatic_complexity.rb


Checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn’t add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one. Blocks that are calls to builtin iteration methods (e.g. `ary.map…​) also add one, others are ignored.

def each_child_node(*types)               # count begins: 1
  unless block_given?                     # unless: +1
    return to_enum(__method__, *types)
children.each do |child|                # each{}: +1
  next unless child.is_a?(Node)         # unless: +1
  yield child if types.empty? ||        # if: +1, ||: +1
end                                       # total: 6

Constant Summary

::RuboCop::Cop::Base - Inherited


Utils::IteratingBlock - Included


Class Attribute Summary

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,

Returns if class supports autocorrect.


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


List of cops that should not try to autocorrect at the same time as this cop.



.callbacks_needed, .cop_name, .department,

Returns an url to view this cops documentation online.


Call for abstract Cop classes.


Override and return the Force class(es) you need to join.


Returns true if the cop name or the cop namespace matches any of the given names.


Register a version requirement for the given gem name.


::RuboCop::ExcludeLimit - Extended


Sets up a configuration option to have an exclude limit tracked.


Instance Attribute Summary

Instance Method Summary

Utils::IteratingBlock - Included


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


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


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


Adds an offense that has no particular location.


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.


Called before any investigation.


Configuration Helpers.

#cop_name, #excluded_file?,

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:


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.


Alias for Base#cop_name.


Called after all on_…​


Called before all on_…​


Called instead of all on_…​


There should be very limited reasons for a Cop to do it’s own parsing.


Called between investigations.

#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,

Reserved for Cop::Cop.


Called to complete an investigation.

#correct, #current_corrector,

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,

Actually private methods.


::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/cyclomatic_complexity.rb', line 42

def complexity_score_for(node)
  return 0 if iterating_block?(node) == false
  return 0 if node.csend_type? && discount_for_repeated_csend?(node)


#count_block?(block) ⇒ Boolean (private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/cyclomatic_complexity.rb', line 49

def count_block?(block)
  KNOWN_ITERATING_METHODS.include? block.method_name