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::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

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, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_ruby_version

Methods included from AST::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?, compatible_external_encoding_for?, directions, double_quotes_acceptable?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, hard_to_type?, 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_supported_styles, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path

Constructor Details

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

Instance Method Details

#allowed_ancestor?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 44

def allowed_ancestor?(node)
  # Don't flag `break(1)`, etc
  keyword_ancestor?(node) && parens_required?(node)
end

#allowed_array_or_hash_element?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 114

def allowed_array_or_hash_element?(node)
  # Don't flag
  # ```
  # { a: (1
  #      ), }
  # ```
  (hash_element?(node) || array_element?(node)) &&
    only_closing_paren_before_comma?(node)
end

#allowed_method_call?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 49

def allowed_method_call?(node)
  # Don't flag `method (arg) { }`
  arg_in_call_with_block?(node) && !parentheses?(node.parent)
end

#allowed_multiple_expression?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 54

def allowed_multiple_expression?(node)
  return false if node.children.size == 1
  ancestor = node.ancestors.first
  return false unless ancestor
  !ancestor.begin_type? && !ancestor.def_type? && !ancestor.block_type?
end

#array_element?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 128

def array_element?(node)
  node.parent && node.parent.array_type?
end

#call_chain_starts_with_int?(begin_node, send_node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 191

def call_chain_starts_with_int?(begin_node, send_node)
  recv = first_part_of_call_chain(send_node)
  recv && recv.int_type? && (parent = begin_node.parent) &&
    parent.send_type? &&
    (parent.method_name == :-@ || parent.method_name == :+@)
end

#check(begin_node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 72

def check(begin_node)
  node = begin_node.children.first
  if keyword_with_redundant_parentheses?(node)
    return offense(begin_node, 'a keyword')
  end
  if disallowed_literal?(begin_node, node)
    return offense(begin_node, 'a literal')
  end
  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 85

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

  return unless method_call_with_redundant_parentheses?(node)
  return if call_chain_starts_with_int?(begin_node, node)

  offense(begin_node, 'a method call')
end

#check_unary(begin_node, node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 94

def check_unary(begin_node, node)
  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')
end

#disallowed_literal?(begin_node, node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 139

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

#empty_parentheses?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 61

def empty_parentheses?(node)
  # Don't flag `()`
  node.children.empty?
end

#first_arg?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 183

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

#hash_element?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 124

def hash_element?(node)
  node.parent && node.parent.pair_type?
end

#hash_literal_as_first_arg?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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

def hash_literal_as_first_arg?(node)
  # Don't flag `method ({key: value})`
  node.children.first.hash_type? && first_arg?(node) &&
    !parentheses?(node.parent)
end

#keyword_ancestor?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 110

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 156

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

  args = *node

  if only_begin_arg?(args)
    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 169

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 106

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

#only_begin_arg?(args) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 179

def only_begin_arg?(args)
  args.size == 1 && args.first && args.first.begin_type?
end

#only_closing_paren_before_comma?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 132

def only_closing_paren_before_comma?(node)
  source_buffer = node.source_range.source_buffer
  line_range = source_buffer.line_range(node.loc.end.line)

  line_range.source =~ /^\s*\)\s*,/
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)
  empty_parentheses?(node) ||
    allowed_ancestor?(node) ||
    hash_literal_as_first_arg?(node) ||
    rescue?(node) ||
    allowed_method_call?(node) ||
    allowed_array_or_hash_element?(node) ||
    allowed_multiple_expression?(node)
end

#raised_to_power_negative_numeric?(begin_node, node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubocop/cop/style/redundant_parentheses.rb', line 145

def raised_to_power_negative_numeric?(begin_node, node)
  return false unless node.numeric_type?

  siblings = begin_node.parent && begin_node.parent.children
  return false if siblings.nil?
  next_sibling = siblings[begin_node.sibling_index + 1]
  base_value = node.children.first

  base_value < 0 && next_sibling == :**
end