UtilityRegistration Fails due to AdapterRegistration

[kevingill]

In zope.app.component

In the SiteManager, you can register Adapters and Utilities.

The default registration.html, (implemented in browser/registration.py) does not handle the case where an object may have an adapter registration.

The offending code is in RegistrationView.registrations:

     registrations = [
           component.getMultiAdapter((r, self.request), IRegistrationDisplay)
           for r in sorted(_registrations(self.context, self.context))
           ]

The result from _registrations may contain classes which do not have an IRegistrationDisplay adapter registered.

The following code resolves the problem:

     registrations = [
            component.getMultiAdapter((r, self.request), IRegistrationDisplay)
            for r in sorted(_registrations(self.context, self.context))
            if zope.component.interfaces.IUtilityRegistration.providedBy(r)
            ]

The resulting exception causes the registration.html view to fail to display after Adapter Registrations are made for a utility.