composition: inherit from parent only if empty, so that a child can override

git-svn-id: https://svn.erp5.org/repos/public/erp5/sandbox/amount_generator@39534 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/mixin/composition.py

@@ -220,9 +220,15 @@ class CompositionMixin:
           effective_set.add(model)
           if 1: #model.test(self): # XXX
             effective_list.append(model)
+    # Inherit from parent only if empty, so that a child can override.
+    # This should not be an issue when a SO line is linked to transformation
+    # and the SO to a STC, because asComposedDocument should be called with
+    # different lists of portal types.
+    if _LEGACY_SIMULATION or not specialise_value_list:
       parent = self.getParentValue()
-    if hasattr(aq_base(parent), 'asComposedDocument'):
+      if getattr(aq_base(parent), 'asComposedDocument', None) is not None:
         parent = parent.asComposedDocument(specialise_type_list)
+        # return parent._effective_model_list, parent.getValueList('specialise')
         specialise_value_list += parent.getValueList('specialise')
         effective_list += [model for model in parent._effective_model_list
                                  if model not in effective_set]