Is there a recommended way or example code somewhere for removing a utility registration from a persistent component registry, when that utility's module no longer exists? The use case is in Plone, which has a local zope.app.cache.ram.IRAMCache utility. Now that Hanno has factored out the RAM cache into zope.ramcache, we'd like the persistent utility to reference zope.ramcache, so that we can remove our zope.app.cache dependency. I've been trying to make this work using a temporary module alias (code below), but something strange is going on. In particular, unghosting the persistent utilities registry is affecting things somehow...before that happens, doing a repr of IRAMCache gives: (Pdb) zope.app.cache.interfaces.ram.IRAMCache <InterfaceClass zope.ramcache.interfaces.ram.IRAMCache> ...(what I'd expect, I guess, given my module alias)...but after the registry is unghosted, it gives: (Pdb) zope.app.cache.interfaces.ram.IRAMCache <InterfaceClass zope.app.cache.interfaces.ram.IRAMCache> ...(which is what I'm actually hoping for, in order to unregister the old utility)...but then I also get: (Pdb) zope.ramcache.interfaces.ram.IRAMCache <InterfaceClass zope.app.cache.interfaces.ram.IRAMCache> ...(e.g., now accessing it via the new module gives a class that thinks its in the old module) Sorry for the rather muddled description, but I haven't been able to really understand what's going on there yet. So what am I missing or doing wrong? Is there a better way to go about this? def relocateRamCacheUtility(portal): # temporary module alias try: import zope.app.cache old_zope_app_cache = zope.app.cache except ImportError: old_zope_app_cache = None import zope.ramcache zope.app.cache = sys.modules['zope.app.cache'] = zope.ramcache sm = getSiteManager(context=portal) # make sure the persistent utilities registry is unghosted before we # reference the old interface name, as it seems to make a difference in # whether it can be unregistered (WTF?) sm.utilities.changed component = sm.getUtility(zope.app.cache.interfaces.ram.IRAMCache) sm.unregisterUtility(component=component, provided=zope.app.cache.interfaces.ram.IRAMCache) import zope.ramcache import pdb; pdb.set_trace( ) sm.registerUtility(factory=zope.ramcache.ram.RAMCache, provided=zope.ramcache.interfaces.ram.IRAMCache) logger.info('Updated the import location of the local IRAMCache utility.') # reset the module alias zope.app.cache = sys.modules['zope.app.cache'] = old_zope_app_cache thanks, David Glick Web Developer ONE/Northwest New tools and strategies for engaging people in protecting the environment http://www.onenw.org davidglick@onenw.org work: (206) 286-1235 x32 mobile: (206) 679-3833 Subscribe to ONEList, our email newsletter! Practical advice for effective online engagement http://www.onenw.org/full_signup