for a multi mandatory, allow [] with allow_empty_list attribut

tiramisu/storage/dictionary/option.py

@@ -32,7 +32,8 @@ class StorageBase(object):
                  '_multi',
                  '_extra',
                  '_warnings_only',
-                 #valeur
+                 '_allow_empty_list',
+                 #value
                  '_default',
                  '_default_multi',
                  #calcul
@@ -41,10 +42,7 @@ class StorageBase(object):
                  '_properties',
                  '_calc_properties',
                  '_val_call',
-                 #'_validator',
-                 #'_validator_params',
-                 #'_callback',
-                 #'_callback_params',
+                 #
                  '_consistencies',
                  '_master_slaves',
                  '_choice_values',
@@ -62,7 +60,7 @@ class StorageBase(object):
                  )
 
     def __init__(self, name, multi, warnings_only, doc, extra, calc_properties,
-                 requires, properties, opt=undefined):
+                 requires, properties, allow_empty_list, opt=undefined):
         self._name = name
         if doc is not undefined:
             self._informations = {'doc': doc}
@@ -81,6 +79,8 @@ class StorageBase(object):
             self._properties = properties
         if opt is not undefined:
             self._opt = opt
+        if allow_empty_list is not False:
+            self._allow_empty_list = allow_empty_list
 
     def _set_default_values(self, default, default_multi):
         if ((self.impl_is_multi() and default != tuple()) or
@@ -298,6 +298,13 @@ class StorageBase(object):
             _multi = 1
         return _multi == 2
 
+    def impl_allow_empty_list(self):
+        try:
+            return self._allow_empty_list
+        except AttributeError:
+            return False
+
+
     def _get_extra(self, key):
         extra = self._extra
         if isinstance(extra, tuple):
@@ -308,7 +315,7 @@ class StorageBase(object):
     def _is_warnings_only(self):
         try:
             return self._warnings_only
-        except:
+        except AttributeError:
             return False
 
     def impl_getdefault(self):