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.'

Constants included from Util

Util::ASGN_NODES, Util::EQUALS_ASGN_NODES, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, 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, #autocorrect?, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, cop_name_with_namespace, cop_type, #debug?, #display_cop_names?, inherited, #join_force?, lint?, #message, non_rails, qualified_cop_name, rails?, #relevant_file?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

issue_deprecation_warning, match_path?, relative_path

Constructor Details

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

Returns a new instance of RedundantSelf.



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 48

def initialize(config = nil, options = nil)
  super
  @allowed_send_nodes = []
  @local_variables = []
end

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 104

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

#on_args(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 78

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

#on_blockarg(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 82

def on_blockarg(node)
  on_argument(node)
end

#on_def(_node) ⇒ Object

Using self.x to distinguish from local variable x



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 70

def on_def(_node)
  @local_variables = []
end

#on_defs(_node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 74

def on_defs(_node)
  @local_variables = []
end

#on_lvasgn(node) ⇒ Object 



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

def on_lvasgn(node)
  lhs, _rhs = *node
  @local_variables << lhs
end

#on_op_asgn(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 63

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



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 56

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

#on_send(node) ⇒ Object

Detect offenses



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# File 'lib/rubocop/cop/style/redundant_self.rb', line 93

def on_send(node)
  receiver, method_name, *_args = *node
  return unless receiver && receiver.type == :self
  return if operator?(method_name) || keyword?(method_name) ||
            constant_name?(method_name) ||
            @allowed_send_nodes.include?(node) ||
            @local_variables.include?(method_name)

  add_offense(node, :expression)
end