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Class: RuboCop::Cop::Lint::AssignmentInCondition

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

Overview

Checks for assignments in the conditions of if/while/until.

AllowSafeAssignment option for safe assignment. By safe assignment we mean putting parentheses around an assignment to indicate "I know I’m using an assignment as a condition. It’s not a mistake."

Examples:

# bad
if some_var = value
  do_something
end

# good
if some_var == value
  do_something
end

AllowSafeAssignment: true (default)

# good
if (some_var = value)
  do_something
end

AllowSafeAssignment: false

# bad
if (some_var = value)
  do_something
end

Cop Safety Information:

  • This cop’s autocorrection is unsafe because it assumes that the author meant to use an assignment result as a condition.

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

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::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::SafeAssignment - 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

#allowed_construct?(asgn_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 82

def allowed_construct?(asgn_node)
  asgn_node.begin_type? || conditional_assignment?(asgn_node)
end

#conditional_assignment?(asgn_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 86

def conditional_assignment?(asgn_node)
  !asgn_node.loc.operator
end

#message(_node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 74

def message(_node)
  if safe_assignment_allowed?
    MSG_WITH_SAFE_ASSIGNMENT_ALLOWED
  else
    MSG_WITHOUT_SAFE_ASSIGNMENT_ALLOWED
  end
end

#on_if(node) Also known as: #on_while, #on_until

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 55

def on_if(node)
  return if node.condition.block_type?

  traverse_node(node.condition) do |asgn_node|
    next :skip_children if skip_children?(asgn_node)
    next if allowed_construct?(asgn_node)

    add_offense(asgn_node.loc.operator) do |corrector|
      next unless safe_assignment_allowed?

      corrector.wrap(asgn_node, '(', ')')
    end
  end
end

#on_until(node)

Alias for #on_if.

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 70

alias on_until on_if

#on_while(node)

Alias for #on_if.

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 69

alias on_while on_if

#skip_children?(asgn_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 90

def skip_children?(asgn_node)
  (asgn_node.call_type? && !asgn_node.assignment_method?) ||
    empty_condition?(asgn_node) ||
    (safe_assignment_allowed? && safe_assignment?(asgn_node))
end

#traverse_node(node, &block) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/lint/assignment_in_condition.rb', line 96

def traverse_node(node, &block)
  # if the node is a block, any assignments are irrelevant
  return if node.block_type?

  result = yield node if ASGN_TYPES.include?(node.type)

  return if result == :skip_children

  node.each_child_node { |child| traverse_node(child, &block) }
end