Class: RuboCop::Cop::Style::UnlessLogicalOperators

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/style/unless_logical_operators.rb


Checks for the use of logical operators in an unless condition. It discourages such code, as the condition becomes more difficult to read and understand.

This cop supports two styles:

  • forbid_mixed_logical_operators (default)

  • forbid_logical_operators

forbid_mixed_logical_operators style forbids the use of more than one type of logical operators. This makes the unless condition easier to read because either all conditions need to be met or any condition need to be met in order for the expression to be truthy or falsey.

forbid_logical_operators style forbids any use of logical operator. This makes it even more easy to read the unless condition as there is only one condition in the expression.


EnforcedStyle: forbid_mixed_logical_operators (default)

# bad
return unless a || b && c
return unless a && b || c
return unless a && b and c
return unless a || b or c
return unless a && b or c
return unless a || b and c

# good
return unless a && b && c
return unless a || b || c
return unless a and b and c
return unless a or b or c
return unless a?

EnforcedStyle: forbid_logical_operators

# bad
return unless a || b
return unless a && b
return unless a or b
return unless a and b

# good
return unless a
return unless a?

Constant Summary

::RuboCop::Cop::Base - Inherited


::RuboCop::Cop::ConfigurableEnforcedStyle - 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

::RuboCop::Cop::ConfigurableEnforcedStyle - 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


[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 62

def_node_matcher :and_with_or?, <<~PATTERN
  (if (and <`or ...> ) ...)


[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 67

def_node_matcher :logical_operator?, <<~PATTERN
  (if ({and or} ... ) ...)

#mixed_logical_operator?(node) ⇒ Boolean (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 83

def mixed_logical_operator?(node)
  or_with_and?(node) ||
    and_with_or?(node) ||
    mixed_precedence_and?(node) ||

#mixed_precedence_and?(node) ⇒ Boolean (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 90

def mixed_precedence_and?(node)
  and_sources = node.condition.each_descendant(:and).map(&:operator)
  and_sources << node.condition.operator if node.condition.and_type?

  !(and_sources.all?('&&') || and_sources.all?('and'))

#mixed_precedence_or?(node) ⇒ Boolean (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 97

def mixed_precedence_or?(node)
  or_sources = node.condition.each_descendant(:or).map(&:operator)
  or_sources << node.condition.operator if node.condition.or_type?

  !(or_sources.all?('||') || or_sources.all?('or'))


[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 71

def on_if(node)
  return unless node.unless?

  if style == :forbid_mixed_logical_operators && mixed_logical_operator?(node)
    add_offense(node, message: FORBID_MIXED_LOGICAL_OPERATORS)
  elsif style == :forbid_logical_operators && logical_operator?(node)
    add_offense(node, message: FORBID_LOGICAL_OPERATORS)


[ GitHub ]

# File 'lib/rubocop/cop/style/unless_logical_operators.rb', line 57

def_node_matcher :or_with_and?, <<~PATTERN
  (if (or <`and ...> ) ...)