revert r9679, which was a mistake, and add better comments.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@10644 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/ERP5Type.py

@@ -458,14 +458,21 @@ class ERP5TypeInformation( FactoryTypeInformation,
                       ' base categories : %s' % (base_category_script_id,
                                             ', '.join(dynamic_base_category_list))
           else:
+            # no base_category needs to be retrieved using the script, we use
+            # a list containing an empty dict to trick the system into
+            # creating one category_value_dict (which will only use statically
+            # defined categories)
             category_result = [{}]
-          # add the result to role_category_list_dict, aggregated with
-          # category_order and statically defined categories
+
           for role in role_text.split(';'):
+            # category_result is a list of dicts that represents the resolved
+            # categories we create a category_value_dict from each of these
+            # dicts aggregated with category_order and statically defined
+            # categories
             role = role.strip()
             role_category_list = role_category_list_dict.setdefault(role, [])
-            category_value_dict = {'category_order':category_order_list}
             for category_dict in category_result:
+              category_value_dict = {'category_order':category_order_list}
               category_value_dict.update(category_dict)
               for c in definition['category']:
                 bc, value = c.split('/', 1)