Class: RuboCop::Cop::Lint::SelfAssignment

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, `::RuboCop::Cop::Base`, `::RuboCop::ExcludeLimit`, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain: self, `::RuboCop::Cop::Base`, `::RuboCop::Cop::AutocorrectLogic`, `::RuboCop::Cop::IgnoredNode`, `::RuboCop::Util`, RuboCop::AST::Sexp
Inherits:	RuboCop::Cop::Base Object RuboCop::Cop::Base RuboCop::Cop::Lint::SelfAssignment
Defined in:	lib/rubocop/cop/lint/self_assignment.rb

Overview

Checks for self-assignments.

Examples:

# bad
foo = foo
foo, bar = foo, bar
Foo = Foo
hash['foo'] = hash['foo']
obj.attr = obj.attr

# good
foo = bar
foo, bar = bar, foo
Foo = Bar
hash['foo'] = hash['bar']
obj.attr = obj.attr2

# good (method calls possibly can return different results)
hash[foo] = hash[foo]

Constant Summary

ASSIGNMENT_TYPE_TO_RHS_TYPE =
# File 'lib/rubocop/cop/lint/self_assignment.rb', line 29

{
  lvasgn: :lvar,
  ivasgn: :ivar,
  cvasgn: :cvar,
  gvasgn: :gvar
}.freeze

MSG =
# File 'lib/rubocop/cop/lint/self_assignment.rb', line 27
```
'Self-assignment detected.'
```

`::RuboCop::Cop::Base` - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

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 a 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

`::RuboCop::Cop::Base` - Inherited

#active_support_extensions_enabled?, #always_autocorrect?, #config, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #processed_source, #string_literals_frozen_by_default?, #target_satisfies_all_gem_version_requirements?

`::RuboCop::Cop::AutocorrectLogic` - Included

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Instance Method Summary

#on_and_asgn(node)

Alias for #on_or_asgn.
#on_casgn(node)
#on_csend(node)

Alias for #on_send.
#on_cvasgn(node)

Alias for #on_lvasgn.
#on_gvasgn(node)

Alias for #on_lvasgn.
#on_ivasgn(node)

Alias for #on_lvasgn.
#on_lvasgn(node) (also: #on_ivasgn, #on_cvasgn, #on_gvasgn)
#on_masgn(node)
#on_or_asgn(node) (also: #on_and_asgn)
#on_send(node) (also: #on_csend)
#handle_attribute_assignment(node) private
#handle_key_assignment(node) private
#multiple_self_assignment?(node) ⇒ Boolean private
#rhs_matches_lhs?(rhs, lhs) ⇒ Boolean private

`::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_gem_version	Returns a gems locked versions (i.e.
#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

#disable_offense, #disable_offense_at_end_of_line, #disable_offense_before_and_after, #disable_offense_with_eol_or_surround_comment, #heredoc_range, #max_line_length, #multiline_ranges, #multiline_string?,
#range_by_lines	Expand the given range to include all of any lines it covers.
#range_of_first_line, #range_overlaps_offense?, #string_continuation?, #surrounding_heredoc?, #surrounding_percent_array?

`::RuboCop::Cop::IgnoredNode` - Included

#ignore_node, #ignored_node?, #part_of_ignored_node?, #ignored_nodes

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#handle_attribute_assignment(node) (private)

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 101


def handle_attribute_assignment(node)
  first_argument = node.first_argument
  return unless first_argument.respond_to?(:arguments) && first_argument.arguments.empty?

  if first_argument.call_type? &&
     node.receiver == first_argument.receiver &&
     first_argument.method_name.to_s == node.method_name.to_s.delete_suffix('=')
    add_offense(node)
  end
end

#handle_key_assignment(node) (private)

[ GitHub ]

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


def handle_key_assignment(node)
  value_node = node.arguments[1]

  if value_node.send_type? && value_node.method?(:[]) &&
     node.receiver == value_node.receiver &&
     !node.first_argument.call_type? &&
     node.first_argument == value_node.first_argument
    add_offense(node)
  end
end

#multiple_self_assignment?(node) ⇒ `Boolean` (private)

[ GitHub ]

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


def multiple_self_assignment?(node)
  lhs = node.lhs
  rhs = node.rhs
  return false unless rhs.array_type?
  return false unless lhs.children.size == rhs.children.size

  lhs.children.zip(rhs.children).all? do |lhs_item, rhs_item|
    rhs_matches_lhs?(rhs_item, lhs_item)
  end
end

#on_and_asgn(node)

Alias for #on_or_asgn.

[ GitHub ]

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


alias on_and_asgn on_or_asgn

#on_casgn(node)

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 56


def on_casgn(node)
  return unless node.rhs&.const_type?

  add_offense(node) if node.namespace == node.rhs.namespace &&
                       node.short_name == node.rhs.short_name
end

#on_csend(node)

Alias for #on_send.

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 43


alias on_csend on_send

#on_cvasgn(node)

Alias for #on_lvasgn.

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 53


alias on_cvasgn on_lvasgn

#on_gvasgn(node)

Alias for #on_lvasgn.

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 54


alias on_gvasgn on_lvasgn

#on_ivasgn(node)

Alias for #on_lvasgn.

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 52


alias on_ivasgn on_lvasgn

#on_lvasgn(node) Also known as: #on_ivasgn, #on_cvasgn, #on_gvasgn

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 45


def on_lvasgn(node)
  return unless node.rhs

  rhs_type = ASSIGNMENT_TYPE_TO_RHS_TYPE[node.type]

  add_offense(node) if node.rhs.type == rhs_type && node.rhs.source == node.lhs.to_s
end

#on_masgn(node)

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 63


def on_masgn(node)
  add_offense(node) if multiple_self_assignment?(node)
end

#on_or_asgn(node) Also known as: #on_and_asgn

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 67


def on_or_asgn(node)
  add_offense(node) if rhs_matches_lhs?(node.rhs, node.lhs)
end

#on_send(node) Also known as: #on_csend

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 36


def on_send(node)
  if node.method?(:[]=)
    handle_key_assignment(node) if node.arguments.size == 2
  elsif node.assignment_method?
    handle_attribute_assignment(node) if node.arguments.size == 1
  end
end

#rhs_matches_lhs?(rhs, lhs) ⇒ `Boolean` (private)

[ GitHub ]

# File 'lib/rubocop/cop/lint/self_assignment.rb', line 85


def rhs_matches_lhs?(rhs, lhs)
  rhs.type == ASSIGNMENT_TYPE_TO_RHS_TYPE[lhs.type] &&
    rhs.children.first == lhs.children.first
end

Class: RuboCop::Cop::Lint::SelfAssignment

Overview

Constant Summary

::RuboCop::Cop::Base - Inherited

Class Attribute Summary

::RuboCop::Cop::Base - Inherited

Class Method Summary

::RuboCop::Cop::Base - Inherited

::RuboCop::ExcludeLimit - Extended

Instance Attribute Summary

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::AutocorrectLogic - Included

Instance Method Summary

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

Instance Method Details

#handle_attribute_assignment(node) (private)

#handle_key_assignment(node) (private)

#multiple_self_assignment?(node) ⇒ Boolean (private)

#on_and_asgn(node)

#on_casgn(node)

#on_csend(node)

#on_cvasgn(node)

#on_gvasgn(node)

#on_ivasgn(node)

#on_lvasgn(node) Also known as: #on_ivasgn, #on_cvasgn, #on_gvasgn

#on_masgn(node)

#on_or_asgn(node) Also known as: #on_and_asgn

#on_send(node) Also known as: #on_csend

#rhs_matches_lhs?(rhs, lhs) ⇒ Boolean (private)

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::ExcludeLimit` - Extended

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::AutocorrectLogic` - Included

`::RuboCop::Cop::Base` - Inherited

`::RuboCop::Cop::AutocorrectLogic` - Included

`::RuboCop::Cop::IgnoredNode` - Included

#multiple_self_assignment?(node) ⇒ `Boolean` (private)

#rhs_matches_lhs?(rhs, lhs) ⇒ `Boolean` (private)