Do not try to create empty nodes with a negative ID.

Author: stefanseefeld

roundup/cgi/form_parser.py

@@ -563,11 +563,11 @@ def parse(self, create=0, num_re=re.compile('^\d+$')):
         # either have a non-empty content property or no property at all. In
         # the latter case, nothing will change.
         for (cn, id), props in all_props.items():
-            if id and id.startswith('-') and not props:
+            if id is not None and id.startswith('-') and not props:
                 # new item (any class) with no content - ignore
                 del all_props[(cn, id)]
             elif isinstance(self.db.classes[cn], hyperdb.FileClass):
-                if id and id.startswith('-'):
+                if id is not None and id.startswith('-'):
                     if not props.get('content', ''):
                         del all_props[(cn, id)]
                 elif props.has_key('content') and not props['content']: