Method: Puppet::Graph::SimpleGraph#path_between

Defined in:

lib/puppet/graph/simple_graph.rb

#path_between(f, t) ⇒ Object

Return an array of the edge-sets between a series of n+1 vertices (f=v0,v1,v2…t=vn)

connecting the two given vertices.  The ith edge set is an array containing all the
edges between v(i) and v(i+1); these are (by definition) never empty.

  * if f == t, the list is empty
  * if they are adjacent the result is an array consisting of
    a single array (the edges from f to t)
  * and so on by induction on a vertex m between them
  * if there is no path from f to t, the result is nil

This implementation is not particularly efficient; it’s used in testing where clarity

is more important than last-mile efficiency.

# File 'lib/puppet/graph/simple_graph.rb', line 429

def path_between(f, t)
  if f == t
    []
  elsif direct_dependents_of(f).include?(t)
    [edges_between(f, t)]
  elsif dependents(f).include?(t)
    m = (dependents(f) & direct_dependencies_of(t)).first
    path_between(f, m) + path_between(m, t)
  else
    nil
  end
end