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`.

The usage of `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.

  • Calling an attribute writer to prevent an local variable assignment.

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

Note we allow uses of `self` with operators because it would be awkward otherwise.

Examples:


# bad
def foo(bar)
  self.baz
end

# good
def foo(bar)
  self.bar  # Resolves name clash with the argument.
end

def foo
  bar = 1
  self.bar  # Resolves name clash with the local variable.
end

def foo
  %w[x y z].select do |bar|
    self.bar == bar  # Resolves name clash with argument of the block.
  end
end

Constant Summary collapse

MSG =
'Redundant `self` detected.'
KERNEL_METHODS =
Kernel.methods(false)

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, #correct, department, #disable_uncorrectable, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #join_force?, lint?, match?, #message, #messages, #parse, qualified_cop_name, #reason_to_not_correct, #relevant_file?, #target_rails_version, #target_ruby_version

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 AST::Sexp

#s

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #correctable?, #disable_offense, #disable_uncorrectable?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, chdir, hidden_dir?, hidden_file_in_not_hidden_dir?, match_path?, pwd, relative_path, reset_pwd, smart_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 52

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

Class Method Details

.autocorrect_incompatible_withObject


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

def self.autocorrect_incompatible_with
  [ColonMethodCall]
end

Instance Method Details

#autocorrect(node) ⇒ Object


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# File 'lib/rubocop/cop/style/redundant_self.rb', line 111

def autocorrect(node)
  lambda do |corrector|
    corrector.remove(node.receiver.source_range)
    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_block(node) ⇒ Object


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# File 'lib/rubocop/cop/style/redundant_self.rb', line 107

def on_block(node)
  add_scope(node, @local_variables_scopes[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 Also known as: on_defs

Using self.x to distinguish from local variable x


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

def on_def(node)
  add_scope(node)
end

#on_lvasgn(node) ⇒ Object


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

def on_lvasgn(node)
  lhs, rhs = *node
  add_lhs_to_local_variables_scopes(rhs, lhs)
end

#on_masgn(node) ⇒ Object


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

def on_masgn(node)
  lhs, rhs = *node
  lhs.children.each do |child|
    add_lhs_to_local_variables_scopes(rhs, child.to_a.first)
  end
end

#on_op_asgn(node) ⇒ Object


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

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 60

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

#on_send(node) ⇒ Object


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# File 'lib/rubocop/cop/style/redundant_self.rb', line 98

def on_send(node)
  return unless node.self_receiver? && regular_method_call?(node)
  return if node.parent&.mlhs_type?

  return if allowed_send_node?(node)

  add_offense(node)
end