1 

     2 try:

     3     rtype, = __args__

     4 except ValueError:

     5     print 'USAGE: cubicweb-ctl shell <instance> detect_cycle.py -- <relation type>'

     6     print

     7 

     8 graph = {}

     9 for fromeid, toeid in rql('Any X,Y WHERE X %s Y' % rtype):

    10     graph.setdefault(fromeid, []).append(toeid)

    11 

    12 from logilab.common.graph import get_cycles

    13 

    14 for cycle in get_cycles(graph):

    15     print 'cycle', '->'.join(str(n) for n in cycle)