ManageIQ/manageiq-ui-classic

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

Checks for the presence of a return inside a begin..end block in assignment contexts. In this situation, the return will result in an exit from the current method, possibly leading to unexpected behavior.

Example:

# bad

@some_variable ||= begin
  return some_value if some_condition_is_met

  do_something
end

Example:

# good

@some_variable ||= begin
  if some_condition_is_met
    some_value
  else
    do_something
  end
end

# good

some_variable = if some_condition_is_met
                  return if another_condition_is_met

                  some_value
                else
                  do_something
                end