update_data use len(data) when size is None, which breaks this method (setData).

define size = 0 when data is None, will prevent len be use update_data and keep the consistency of getData() and setData().

Other alternative should monkey patch update_data or avoid his usage removing "if/else". 



git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@29036 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/Document.py

@@ -1416,11 +1416,17 @@ class Document(PermanentURLMixIn, XMLObject, UrlMixIn, ConversionCacheMixin, Sna
       be a interface for all classes which can act as a File.
     """
     size = None
+    # update_data use len(data) when size is None, which breaks this method.
+    # define size = 0 will prevent len be use and keep the consistency of 
+    # getData() and setData()
+    if data is None:
+      size = 0
     if not isinstance(data, Pdata) and data is not None:
       file = cStringIO.StringIO(data)
       data, size = self._read_data(file)
     if getattr(self, 'update_data', None) is not None:
-      self.update_data(data, size=size) # We call this method to make sure size is set and caches reset
+      # We call this method to make sure size is set and caches reset
+      self.update_data(data, size=size)
     else:
       self._baseSetData(data) # XXX - It would be better to always use this accessor
       self.size=size # Using accessor or caching method would be better