Class: RuboCop::Cop::Style::RedundantParentheses

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

Overview

This cop checks for redundant parentheses.

Examples:


# bad
(x) if ((y.z).nil?)

# good
x if y.z.nil?

Constant Summary collapse

ALLOWED_LITERALS = 
[:irange, :erange].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, Util::STRING_ESCAPES, Util::STRING_ESCAPE_REGEX

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods included from Parentheses

#autocorrect, #parens_required?

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?, #excluded_file?, #extra_details?, inherited, #initialize, #join_force?, lint?, match?, #message, 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_body

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?, first_part_of_call_chain, interpret_string_escapes, line_range, move_pos, numeric_range_size, on_node, operator?, parentheses?, parenthesized_call?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, ternary_op?, to_string_literal, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, hidden?, issue_deprecation_warning, match_path?, relative_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#check(begin_node) ⇒ Object 



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

def check(begin_node)
  node = begin_node.children.first
  if keyword_with_redundant_parentheses?(node)
    return offense(begin_node, 'a keyword')
  end
  return offense(begin_node, 'a literal') if disallowed_literal?(node)
  return offense(begin_node, 'a variable') if node.variable?
  return offense(begin_node, 'a constant') if node.const_type?
  check_send(begin_node, node) if node.send_type?
end

#check_send(begin_node, node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 59

def check_send(begin_node, node)
  if node.unary_operation?
    return if begin_node.chained?

    # parens are not redundant in `(!recv.method arg)`
    node = node.children.first while node.unary_operation?
    if node.send_type?
      return unless method_call_with_redundant_parentheses?(node)
    end

    offense(begin_node, 'an unary operation')
  else
    return unless method_call_with_redundant_parentheses?(node)
    offense(begin_node, 'a method call')
  end
end

#disallowed_literal?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 84

def disallowed_literal?(node)
  node.literal? && !ALLOWED_LITERALS.include?(node.type)
end

#first_arg?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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

def first_arg?(node)
  send_node = node.parent
  return false unless send_node && send_node.send_type?

  _receiver, _method_name, *args = *send_node
  node.equal?(args.first)
end

#keyword_ancestor?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 80

def keyword_ancestor?(node)
  node.parent && node.parent.keyword?
end

#keyword_with_redundant_parentheses?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 88

def keyword_with_redundant_parentheses?(node)
  return false unless node.keyword?
  return true if node.special_keyword?

  args = *node

  if args.size == 1 && args.first && args.first.begin_type?
    parentheses?(args.first)
  else
    args.empty? || parentheses?(node)
  end
end

#method_call_with_redundant_parentheses?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 101

def method_call_with_redundant_parentheses?(node)
  return false unless node.send_type?
  return false if node.keyword_not?
  return false if range_end?(node)

  send_node, args = method_node_and_args(node)

  args.empty? || parentheses?(send_node) || square_brackets?(send_node)
end

#offense(node, msg) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 76

def offense(node, msg)
  add_offense(node, :expression, "Don't use parentheses around #{msg}.")
end

#on_begin(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 29

def on_begin(node)
  return if !parentheses?(node) || parens_allowed?(node)
  check(node)
end

#parens_allowed?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 34

def parens_allowed?(node)
  child  = node.children.first
  parent = node.parent

  # don't flag `break(1)`, etc
  (keyword_ancestor?(node) && parens_required?(node)) ||
    # don't flag `method ({key: value})`
    (child.hash_type? && first_arg?(node) && !parentheses?(parent)) ||
    # don't flag `rescue(ExceptionClass)`
    rescue?(node) ||
    # don't flag `method (arg) { }`
    (arg_in_call_with_block?(node) && !parentheses?(parent))
end