Class: RuboCop::Cop::Style::RedundantSelf

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/style/redundant_self.rb

Overview

This cop checks for redundant uses of ‘self`.

‘self` is only needed when:

  • Sending a message to same object with zero arguments in presence of a method name clash with an argument or a local variable.

    Note, with using explicit self you can only send messages with public or protected scope, you cannot send private messages this way.

    Example:

    def bar

    :baz

    end

    def foo(bar)

    self.bar # resolves name clash with argument

    end

    def foo2

    bar = 1
self.bar # resolves name clash with local variable

    end

  • Calling an attribute writer to prevent an local variable assignment

    attr_writer :bar

    def foo

    self.bar= 1 # Make sure above attr writer is called

    end

Special cases:

We allow uses of ‘self` with operators because it would be awkward otherwise.

Constant Summary collapse

MSG = 
'Redundant `self` detected.'.freeze

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #correct, #debug?, #details, #display_cop_names?, #display_style_guide?, #duplicate_location?, #excluded_file?, #extra_details?, #find_location, #highlights, inherited, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #reference_url, #relevant_file?, #style_guide_url, #target_ruby_version

Methods included from Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, comment_line?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_distance, line_range, move_pos, needs_escaping?, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, preceed?, range_between, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, to_string_literal, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path

Constructor Details

#initialize(config = nil, options = nil) ⇒ RedundantSelf

Returns a new instance of RedundantSelf.



49
50
51
52
53
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 49

def initialize(config = nil, options = nil)
  super
  @allowed_send_nodes = []
  @local_variables_scopes = Hash.new { |hash, key| hash[key] = [] }
end

Instance Method Details

#autocorrect(node) ⇒ Object 



104
105
106
107
108
109
110
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 104

def autocorrect(node)
  receiver, _method_name, *_args = *node
  lambda do |corrector|
    corrector.remove(receiver.source_range)
    corrector.remove(node.loc.dot)
  end
end

#on_args(node) ⇒ Object 



79
80
81
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 79

def on_args(node)
  node.children.each { |arg| on_argument(arg) }
end

#on_blockarg(node) ⇒ Object 



83
84
85
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 83

def on_blockarg(node)
  on_argument(node)
end

#on_def(node) ⇒ Object

Using self.x to distinguish from local variable x



71
72
73
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 71

def on_def(node)
  add_scope(node)
end

#on_defs(node) ⇒ Object 



75
76
77
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 75

def on_defs(node)
  add_scope(node)
end

#on_lvasgn(node) ⇒ Object 



87
88
89
90
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 87

def on_lvasgn(node)
  lhs, _rhs = *node
  @local_variables_scopes[node] << lhs
end

#on_op_asgn(node) ⇒ Object 



64
65
66
67
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 64

def on_op_asgn(node)
  lhs, _op, _rhs = *node
  allow_self(lhs)
end

#on_or_asgn(node) ⇒ Object Also known as: on_and_asgn

Assignment of self.x



57
58
59
60
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 57

def on_or_asgn(node)
  lhs, _rhs = *node
  allow_self(lhs)
end

#on_send(node) ⇒ Object

Detect offenses



94
95
96
97
98
99
100
101
102
 
# File 'lib/rubocop/cop/style/redundant_self.rb', line 94

def on_send(node)
  receiver, method_name, *_args = *node
  return unless receiver && receiver.self_type?
  return unless regular_method_call?(node)

  return if @allowed_send_nodes.include?(node) ||
            @local_variables_scopes[node].include?(method_name)
  add_offense(node, :expression)
end