--- a/migration.py	Fri Jun 17 18:51:01 2011 +0200
+++ b/migration.py	Sat Jun 18 23:27:23 2011 +0200
@@ -492,6 +492,8 @@
                         self.warnings.append(
                             'cube %s depends on %s but constraint badly '
                             'formatted: %s' % (cube, name, constraint))
+                else:
+                    self.reverse_dependencies[name].add( (None, None, cube) )
         # check consistency
         for cube, versions in sorted(self.reverse_dependencies.items()):
             oper, version, source = None, None, None
@@ -517,5 +519,7 @@
                 if oper in ('>=','='):
                     if lower_strict:
                         self.errors.append( ('update', cube, version, source) )
+                elif oper is None:
+                    pass # no constraint on version
                 else:
                     print 'unknown operator', oper