_calc_requirement is a set, not a tuple

tiramisu/config.py

@@ -669,6 +669,8 @@ def mandatory_warnings(config):
             include_groups=True):
         try:
             config._getattr(path, force_properties=frozenset(('mandatory',)))
+            # XXX raise Exception("ca passe ici")
+            # XXX depuis l'exterieur on donne un paht maintenant ! perturbant !
         except PropertiesOptionError, err:
             if err.proptype == ['mandatory']:
                 yield path

tiramisu/option.py

@@ -1009,4 +1009,4 @@ def validate_requires_arg(requires, name):
                                      require[5])
             ret_action.append(req)
         ret.append(tuple(ret_action))
-    return tuple(config_action.keys()), tuple(ret)
+    return frozenset(config_action.keys()), tuple(ret)