class RuboCop::Cop::Style::MethodDefParentheses

end
do_something
last_descriptive_var_name)
another_descriptive_var_name,
def foo(descriptive_var_name,
end
num1 + num2
def bar num1, num2
# good
end
do_something
last_descriptive_var_name
another_descriptive_var_name,
def foo descriptive_var_name,
end
num1 + num2
def bar(num1, num2)
# bad
# but prefers parentheses when arguments span multiple lines.
# parentheses when method definition arguments fit on single line,
# The ‘require_no_parentheses_except_multiline` style prefers no
@example EnforcedStyle: require_no_parentheses_except_multiline
end
do_something
last_descriptive_var_name
another_descriptive_var_name,
def foo descriptive_var_name,
end
num1 + num2
def bar num1, num2
# good
end
do_something
last_descriptive_var_name)
another_descriptive_var_name,
def foo(descriptive_var_name,
end
num1 + num2
def bar(num1, num2)
# bad
# to never use parentheses
# The `require_no_parentheses` style requires method definitions
@example EnforcedStyle: require_no_parentheses
end
do_something
last_descriptive_var_name)
another_descriptive_var_name,
def foo(descriptive_var_name,
end
num1 + num2
def bar(num1, num2)
# good
end
do_something
last_descriptive_var_name
another_descriptive_var_name,
def foo descriptive_var_name,
end
num1 + num2
def bar num1, num2
# bad
# to always use parentheses
# The `require_parentheses` style requires method definitions
@example EnforcedStyle: require_parentheses (default)
Removing the parens would be a syntax error here.
5. Argument lists containing an anonymous block forwarding (`&`)
4. Argument lists containing an anonymous keyword rest arguments forwarding (`**`)
3. Argument lists containing an anonymous rest arguments forwarding (`*`)
2. Argument lists containing a `forward-arg` (`…`)
1. Endless methods
Regardless of style, parentheses are necessary for:
definitions. Both instance and class/singleton methods are checked.
Checks for parentheses around the arguments in method

def anonymous_arguments?(node) 

def anonymous_arguments?(node)
  return true if node.arguments.any? do |arg|
    arg.forward_arg_type? || arg.restarg_type? || arg.kwrestarg_type?
  end
  return false unless (last_argument = node.arguments.last)
  last_argument.blockarg_type? && last_argument.name.nil?
end

def arguments_without_parentheses?(node) 

def arguments_without_parentheses?(node)
  node.arguments? && !parentheses?(node.arguments)
end

def correct_arguments(arg_node, corrector) 

def correct_arguments(arg_node, corrector)
  corrector.replace(arg_node.loc.begin, ' ')
  corrector.remove(arg_node.loc.end)
end

def forced_parentheses?(node) 

def forced_parentheses?(node)
  # Regardless of style, parentheses are necessary for:
  # 1. Endless methods
  # 2. Argument lists containing a `forward-arg` (`...`)
  # 3. Argument lists containing an anonymous rest arguments forwarding (`*`)
  # 4. Argument lists containing an anonymous keyword rest arguments forwarding (`**`)
  # 5. Argument lists containing an anonymous block forwarding (`&`)
  # Removing the parens would be a syntax error here.
  node.endless? || anonymous_arguments?(node)
end

def missing_parentheses(node) 

def missing_parentheses(node)
  location = node.arguments.source_range
  add_offense(location, message: MSG_MISSING) do |corrector|
    add_parentheses(node.arguments, corrector)
    unexpected_style_detected 'require_no_parentheses'
  end
end

def on_def(node) 

def on_def(node)
  return if forced_parentheses?(node)
  args = node.arguments
  if require_parentheses?(args)
    if arguments_without_parentheses?(node)
      missing_parentheses(node)
    else
      correct_style_detected
    end
  elsif parentheses?(args)
    unwanted_parentheses(args)
  else
    correct_style_detected
  end
end

def require_parentheses?(args) 

def require_parentheses?(args)
  style == :require_parentheses ||
    (style == :require_no_parentheses_except_multiline && args.multiline?)
end

def unwanted_parentheses(args) 

def unwanted_parentheses(args)
  add_offense(args, message: MSG_PRESENT) do |corrector|
    # offense is registered on args node when parentheses are unwanted
    correct_arguments(args, corrector)
    unexpected_style_detected 'require_parentheses'
  end
end