transitive_deps.rb

#! /usr/bin/env ruby

$deps = {
  :network => [ :foo, :bar, :baz],
  :foo => [:testsuite, :yast2],
  :bar => [:yast2, :testsuite],
  :baz => [:yast2, :testsuite],
  :yast2 => [:testsuite],
  :testsuite => []
}

class Array
  # For debugging, let's "mute" uniq.
  # I cannot think of a reasonable implementation that would keep
  # other element than the first occurring.
  def evil_uniq
#    uniq
    dup
  end
end

def transitive_deps0(target)
  deps_of_deps = $deps[target].map { |d| transitive_deps0(d) }
  (deps_of_deps.reduce([], :+) + $deps[target]).evil_uniq
end

def transitive_deps1(target)
  deps_of_deps = $deps[target].map { |d| transitive_deps1(d) }
  deps_of_deps.reduce($deps[target], :+).evil_uniq
end

puts "original"
p transitive_deps0(:network)
puts "reduced"
p transitive_deps1(:network)