+
−from __future__ import print_function
+
−
+
−try:
+
−    rtype, = __args__
+
−except ValueError:
+
−    print('USAGE: cubicweb-ctl shell <instance> detect_cycle.py -- <relation type>')
+
−    print()
+
−
+
−graph = {}
+
−for fromeid, toeid in rql('Any X,Y WHERE X %s Y' % rtype):
+
−    graph.setdefault(fromeid, []).append(toeid)
+
−
+
−from logilab.common.graph import get_cycles
+
−
+
−for cycle in get_cycles(graph):
+
−    print('cycle', '->'.join(str(n) for n in cycle))