1 from __future__ import print_function

     2 

     3 try:

     4     rtype, = __args__

     5 except ValueError:

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

     7     print()

     8 

     9 graph = {}

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

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

    12 

    13 from logilab.common.graph import get_cycles

    14 

    15 for cycle in get_cycles(graph):

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