Class: RuboCop::Cop::Style::RedundantSelfAssignment

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: self, `::RuboCop::Cop::RangeHelp`, `::RuboCop::Cop::Base`, `::RuboCop::Cop::AutocorrectLogic`, `::RuboCop::Cop::IgnoredNode`, `::RuboCop::Util`, RuboCop::AST::Sexp
Inherits:	RuboCop::Cop::Base Object RuboCop::Cop::Base RuboCop::Cop::Style::RedundantSelfAssignment
Defined in:	lib/rubocop/cop/style/redundant_self_assignment.rb

Overview

Checks for places where redundant assignments are made for in place modification methods.

Examples:

# bad
args = args.concat(ary)
hash = hash.merge!(other)

# good
args.concat(foo)
args += foo
hash.merge!(other)

# bad
self.foo = foo.concat(ary)

# good
foo.concat(ary)
self.foo += ary

Cop Safety Information:

This cop is unsafe, because it can produce false positives for user defined methods having one of the expected names, but not modifying its receiver in place.

Constant Summary

ASSIGNMENT_TYPE_TO_RECEIVER_TYPE =
# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 45
```
{
  lvasgn: :lvar,
  ivasgn: :ivar,
  cvasgn: :cvar,
  gvasgn: :gvar
}.freeze
```

METHODS_RETURNING_SELF =
# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 38

%i[
  append clear collect! compare_by_identity concat delete_if
  fill initialize_copy insert keep_if map! merge! prepend push
  rehash replace reverse! rotate! shuffle! sort! sort_by!
  transform_keys! transform_values! unshift update
].to_set.freeze

MSG =
# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 35

'Redundant self assignment detected. ' \
'Method `%<method_name>s` modifies its receiver in place.'

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

EMPTY_OFFENSES, RESTRICT_ON_SEND

`::RuboCop::Cop::RangeHelp` - Included

BYTE_ORDER_MARK, NOT_GIVEN

Class Attribute Summary

`::RuboCop::Cop::AutoCorrector` - Extended

support_autocorrect?

`::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_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_send(node)
#correction_range(node) private
#method_returning_self?(method_name) ⇒ Boolean private
#redundant_assignment?(node) ⇒ Boolean private
#redundant_nonself_assignment?(node, receiver, method_name) private
#redundant_self_assignment?(node, method_name) private

`::RuboCop::Cop::RangeHelp` - Included

#add_range, #column_offset_between,
#contents_range	A range containing only the contents of a literal with delimiters (e.g.
#directions,
#effective_column	Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value.
#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range

`::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

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

#correction_range(node) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 112


def correction_range(node)
  range_between(node.source_range.begin_pos, node.first_argument.source_range.begin_pos)
end

#method_returning_self?(method_name) ⇒ `Boolean` (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 81


def method_returning_self?(method_name)
  METHODS_RETURNING_SELF.include?(method_name)
end

#on_cvasgn(node)

Alias for #on_lvasgn.

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 66


alias on_cvasgn on_lvasgn

#on_gvasgn(node)

Alias for #on_lvasgn.

[ GitHub ]

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


alias on_gvasgn on_lvasgn

#on_ivasgn(node)

Alias for #on_lvasgn.

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 65


alias on_ivasgn on_lvasgn

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

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 52


def on_lvasgn(node)
  lhs, rhs = *node
  receiver, method_name, = *rhs
  return unless receiver && method_returning_self?(method_name)

  receiver_type = ASSIGNMENT_TYPE_TO_RECEIVER_TYPE[node.type]
  return unless receiver.type == receiver_type && receiver.children.first == lhs

  message = format(MSG, method_name: method_name)
  add_offense(node.loc.operator, message: message) do |corrector|
    corrector.replace(node, rhs.source)
  end
end

#on_send(node)

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 69


def on_send(node)
  return unless node.assignment_method?
  return unless redundant_assignment?(node)

  message = format(MSG, method_name: node.first_argument.method_name)
  add_offense(node.loc.operator, message: message) do |corrector|
    corrector.remove(correction_range(node))
  end
end

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

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 105


def redundant_assignment?(node)
  receiver_name = node.method_name.to_s[0...-1].to_sym

  redundant_self_assignment?(node, receiver_name) ||
    redundant_nonself_assignment?(node, node.receiver, receiver_name)
end

#redundant_nonself_assignment?(node, receiver, method_name) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 96


def_node_matcher :redundant_nonself_assignment?, <<~PATTERN
  (send
    %1 _
    (send
      (send
        %1 %2) #method_returning_self?
      ...))
PATTERN

#redundant_self_assignment?(node, method_name) (private)

[ GitHub ]

# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 86


def_node_matcher :redundant_self_assignment?, <<~PATTERN
  (send
    (self) _
    (send
      (send
        {(self) nil?} %1) #method_returning_self?
      ...))
PATTERN

Class: RuboCop::Cop::Style::RedundantSelfAssignment

Overview

Constant Summary

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::RangeHelp - Included

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::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::RangeHelp - Included

::RuboCop::Cop::Base - Inherited

::RuboCop::Cop::AutocorrectLogic - Included

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

Instance Method Details

#correction_range(node) (private)

#method_returning_self?(method_name) ⇒ Boolean (private)

#on_cvasgn(node)

#on_gvasgn(node)

#on_ivasgn(node)

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

#on_send(node)

#redundant_assignment?(node) ⇒ Boolean (private)

#redundant_nonself_assignment?(node, receiver, method_name) (private)

#redundant_self_assignment?(node, method_name) (private)

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

`::RuboCop::Cop::RangeHelp` - Included

`::RuboCop::Cop::AutoCorrector` - Extended

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

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

`::RuboCop::ExcludeLimit` - Extended

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

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

`::RuboCop::Cop::RangeHelp` - Included

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

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

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

#method_returning_self?(method_name) ⇒ `Boolean` (private)

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