Infinite Recursion Error (Catalog)
There is a "feature" in the catalog where you can acquire attributes for metadata and indexes. For instance if you want to index the MD5 for a body of a text document. You dont want to build this into the attribute of the object. So what you can do is create a Python Script with a ID of getMD5 and then create a FieldIndex called getMD5 (or that would be the indexed attributes). The same can happen with regards to the "metadata" tab in the Catalog ZMI. Which is the data that is available on a brain/result when you query a catalog. But, this can work against you.
Say I create a index or a metadata attribute I want to catalog on called
Materials which is a
attribute on some objects. But I have a folder in the root of the site called Materials. Well
when indexing a object that does not have Materials as a attribute will acquire the folder in the
portal site. This is a source of confusion for newbies.
One way to go around this is to prefix your indexed/metadata. That is usually ugly. Plone currently has a mechanism to ensure that you will not bite yourself - i.e. allowed IDs for objects
are not allowed to be the same as indexes/metadata in the catalog. But if you create a folder,
Materials then add a metadata or index in the catalog with the same name - it will bite you.