Class: RuboCop::Cop::Metrics::BlockNesting

Relationships & Source Files
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/block_nesting.rb


Checks for excessive nesting of conditional and looping constructs.

You can configure if blocks are considered using the CountBlocks and CountModifierForms options. When both are set to false (the default) blocks and modifier forms are not counted towards the nesting level. Set them to true to include these in the nesting level calculation as well.

The maximum level of nesting allowed is configurable.

Constant Summary

::RuboCop::Cop::Base - Inherited


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

::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 Attribute Details

#count_blocks?Boolean (readonly, private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 62

def count_blocks?
  cop_config.fetch('CountBlocks', false)

#count_modifier_forms?Boolean (readonly, private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 66

def count_modifier_forms?
  cop_config.fetch('CountModifierForms', false)

Instance Method Details

#check_nesting_level(node, max, current_level) (private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 28

def check_nesting_level(node, max, current_level)
  if consider_node?(node)
    current_level += 1 if count_if_block?(node)
    if current_level > max
      self.max = current_level
      unless part_of_ignored_node?(node)
        add_offense(node, message: message(max)) { ignore_node(node) }

  node.each_child_node do |child_node|
    check_nesting_level(child_node, max, current_level)

#consider_node?(node) ⇒ Boolean (private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 52

def consider_node?(node)
  return true if NESTING_BLOCKS.include?(node.type)

  count_blocks? && (node.block_type? || node.numblock_type?)

#count_if_block?(node) ⇒ Boolean (private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 44

def count_if_block?(node)
  return true unless node.if_type?
  return false if node.elsif?
  return count_modifier_forms? if node.modifier_form?


#message(max) (private)

[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 58

def message(max)
  "Avoid more than #{max} levels of block nesting."


[ GitHub ]

# File 'lib/rubocop/cop/metrics/block_nesting.rb', line 19

def on_new_investigation
  return if processed_source.blank?

  max = cop_config['Max']
  check_nesting_level(processed_source.ast, max, 0)