[Zope] bad ZCatalog behavior

[Andy Altepeter]

Hi there,

There seems to be a problem with my ZCatalog, and it seems to be getting worse 
as time goes by.  When my CatalogPathAware objects unindex themselves, 
sometimes I get an attribute error like:

AttributeError: 'str' object has no attribute 'append' 

Traceback (innermost last):
  Module ZPublisher.Publish, line 101, in publish
  Module ZPublisher.mapply, line 88, in mapply
  Module ZPublisher.Publish, line 39, in call_object
  Module Products.FileSystemSite.FSPythonScript, line 104, in __call__
  Module Shared.DC.Scripts.Bindings, line 306, in __call__
  Module Shared.DC.Scripts.Bindings, line 343, in _bindAndExec
  Module Products.FileSystemSite.FSPythonScript, line 160, in _exec
  Module None, line 33, in tab_status_approve
   - <FSPythonScript 
at /silva/service_views/Silva/edit/VersionedContent/tab_status_approve used 
for /silva/service_views/SilvaDocument/edit/VersionedContent/Document>
   - Line 33
  Module Products.Silva.Versioning, line 125, in approve_version
  Module Products.Silva.Versioning, line 512, in _update_publication_status
  Module Products.Silva.VersionedContent, line 334, in _unindex_version
  Module Products.Silva.Version, line 191, in unindex_object
  Module Products.ZCatalog.ZCatalog, line 558, in uncatalog_object
  Module Products.ZCatalog.Catalog, line 411, in uncatalogObject
  Module Products.ZCTextIndex.ZCTextIndex, line 181, in unindex_object
  Module Products.ZCTextIndex.OkapiIndex, line 68, in unindex_doc
  Module Products.ZCTextIndex.BaseIndex, line 176, in unindex_doc
  Module Products.ZCTextIndex.BaseIndex, line 303, in _del_wordinfo
  Module ZODB.Connection, line 562, in setstate
  Module ZODB.Connection, line 601, in _set_ghost_state
AttributeError: 'str' object has no attribute 'append'

In the logfile, the last line of code is shown in the traceback:
  File "/export1/Zope-2.7.2-0/lib/python/ZODB/Connection.py", line 601, in 
_set_ghost_state
    state = unpickler.load()

Perhaps this is a ZEO issue.  I'm using Zope-2.7.2-0 with ZEO.  Both the zeo 
server and the client are on the same box.  The zeo logfile reports no errors 
when this occurs.

Any ideas why this may be happening?