class RuboCop::Cop::Lint::SafeNavigationChain

The safe navigation operator returns nil if the receiver is nil. If you chain an ordinary method call after a safe navigation operator, it raises NoMethodError. We should use a safe navigation operator after a safe navigation operator. This cop checks for the problem outlined above.

@example

# bad

x&.foo.bar
x&.foo + bar
x&.foo[bar]

@example

# good

x&.foo&.bar
x&.foo || bar

Constants

MSG

Public Instance Methods

on_send(node) click to toggle source
# File lib/rubocop/cop/lint/safe_navigation_chain.rb, line 39
def on_send(node)
  bad_method?(node) do |safe_nav, method|
    return if nil_methods.include?(method)

    method_chain = method_chain(node)
    location =
      Parser::Source::Range.new(node.loc.expression.source_buffer,
                                safe_nav.loc.expression.end_pos,
                                method_chain.loc.expression.end_pos)
    add_offense(node, location: location)
  end
end

Private Instance Methods

method_chain(node) click to toggle source
# File lib/rubocop/cop/lint/safe_navigation_chain.rb, line 54
def method_chain(node)
  chain = node
  while chain.send_type?
    chain = chain.parent if chain.parent &&
                            %i[send csend].include?(chain.parent.type)
    break
  end
  chain
end