class RuboCop::Cop::Performance::RedundantMerge

This cop identifies places where `Hash#merge!` can be replaced by `Hash#[]=`.

@example

hash.merge!(a: 1)
hash.merge!({'key' => 'value'})
hash.merge!(a: 1, b: 2)

Constants

AREF_ASGN
MSG

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 41
def autocorrect(node)
  redundant_merge(node) do |receiver, pairs|
    lambda do |corrector|
      new_source = to_assignments(receiver, pairs).join("\n")

      parent = node.parent
      if parent && pairs.size > 1
        if modifier_flow_control(parent)
          new_source = rewrite_with_modifier(node, parent, new_source)
          node = parent
        else
          padding = "\n#{leading_spaces(node)}"
          new_source.gsub!(/\n/, padding)
        end
      end

      corrector.replace(node.source_range, new_source)
    end
  end
end
on_send(node) click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 23
def on_send(node)
  redundant_merge(node) do |receiver, pairs|
    if node.value_used?
      parent = node.parent
      grandparent = parent.parent if parent.begin_type?
      second_arg = each_with_object_node(grandparent || parent)
      next if second_arg.nil?
      next unless receiver.loc.name.source == second_arg.loc.name.source
    end
    next if pairs.size > 1 && !receiver.pure?
    next if pairs.size > max_key_value_pairs

    assignments = to_assignments(receiver, pairs).join('; ')
    message = format(MSG, assignments, node.source)
    add_offense(node, :expression, message)
  end
end

Private Instance Methods

indent_width() click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 90
def indent_width
  @config.for_cop('IndentationWidth')['Width'] || 2
end
leading_spaces(node) click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 86
def leading_spaces(node)
  node.source_range.source_line[/\A\s*/]
end
max_key_value_pairs() click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 98
def max_key_value_pairs
  cop_config['MaxKeyValuePairs'].to_i
end
modifier?(node) click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 94
def modifier?(node)
  node.loc.respond_to?(:end) && node.loc.end.nil?
end
rewrite_with_modifier(node, parent, new_source) click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 77
def rewrite_with_modifier(node, parent, new_source)
  cond, = *parent
  padding = "\n#{(' ' * indent_width) + leading_spaces(node)}"
  new_source.gsub!(/\n/, padding)

  parent.loc.keyword.source << ' ' << cond.source << padding <<
    new_source << "\n" << leading_spaces(node) << 'end'
end
to_assignments(receiver, pairs) click to toggle source
# File lib/rubocop/cop/performance/redundant_merge.rb, line 64
def to_assignments(receiver, pairs)
  pairs.map do |pair|
    key, value = *pair
    key_src = if key.sym_type? && !key.source.start_with?(':')
                ":#{key.source}"
              else
                key.source
              end

    format(AREF_ASGN, receiver.source, key_src, value.source)
  end
end