[login] redirect to real instance root if no postlogin_path is provided When not postlogin_path is provided, the login form issue a redirect to "/". The instance root may not be at "/" on the server. Then issuing a redirect to "/" send the user to the wrong location. We now redirect to "." which works fine because the "login" controller a direct children of instance root (http://babar.com/instance/login). All other redirection of the login controller use relative path too and then rely on this relative path from the login controleur to the instance root. This mechanism may be considered fragile and may deserve a proper fix. but this is to be discussed and implemented in another changeset.

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)