class RuboCop::Cop::Metrics::CyclomaticComplexity

Checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one. Blocks that are calls to builtin iteration methods (e.g. `ary.map{…}) also add one, others are ignored.

def each_child_node(*types)               # count begins: 1
  unless block_given?                     # unless: +1
    return to_enum(__method__, *types)

  children.each do |child|                # each{}: +1
    next unless child.is_a?(Node)         # unless: +1

    yield child if types.empty? ||        # if: +1, ||: +1
                   types.include?(child.type)
  end

  self
end                                       # total: 6

Constants

COUNTED_NODES
MSG

Private Instance Methods

complexity_score_for(node) click to toggle source
# File lib/rubocop/cop/metrics/cyclomatic_complexity.rb, line 42
def complexity_score_for(node)
  return 0 if iterating_block?(node) == false
  return 0 if node.csend_type? && discount_for_repeated_csend?(node)

  1
end
count_block?(block) click to toggle source
# File lib/rubocop/cop/metrics/cyclomatic_complexity.rb, line 49
def count_block?(block)
  KNOWN_ITERATING_METHODS.include? block.method_name
end