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 class 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 inherited from Cop

Cop::OPERATOR_METHODS

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offences, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offence, all, #autocorrect?, #convention, #cop_config, cop_name, #cop_name, cop_type, #debug?, #ignore_node, inherited, lint?, #message, rails?, style?, #warning

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_action(node) ⇒ Object 



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

def autocorrect_action(node)
  @corrections << lambda do |corrector|
    corrector.replace(node.loc.expression,
                      node.loc.expression.source.gsub(/self\./, ''))
  end
end

#on_arg(node) ⇒ Object 



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

def on_arg(node)
  on_argument(node)
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 offences



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

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