[ldap] simplify connection handling
since we deleted ldapuser source, we don't need anymore the get_connection and
ConnectionWrapper stuff (that was used to put the ldap connection into the cnxset).
Also, we should simply let connection errors propagate so this is properly reported
to import logs.
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)