[Zope3-dev] Need help with JobBoardEx

[Guido van Rossum]

I haven't made much progress with this problem, except to rule out a
bunch of things.

The JobBoard code itself still works; however the configuration parser
doesn't want to believe that the JobBoard class is a factory.  Here's
the ZCML (slightly different from CVS, but it doesn't make a
difference):

<content class=".JobList.">
  <factory
      id="JobList"
      permission="Zope.ManageContent"
      title="Job List"
      description="A Job List" />
  <allow interface=".IJobList." />
  <implements interface="Zope.App.OFS.Container.IContainer.IItemContainer" />
</content>

It appears that the <factory> directive invokes the provideFactory()
method of the GlobalFactoryService class (in
Zope/ComponentArchitecture/GlobalFactoryService.py):

    def provideFactory(self, name, factory):
        """See IGlobalFactoryService interface"""
        verifyObject(IFactory, factory)
        self.__factories[name] = factory

If I comment out the call to verifyObject() everything works as
expected.  Adding some print statements (and a call to
trustedRemoveSecurityProxy) show that the factory object that causes
the failure is a security proxy for a ClassFactory instance whose
_class attribute is the JobList class.

But here's the mystery: look at the way the class
Zope.App.OFS.Content.Image.Image.Image is configured; it's very similar:

  <content class=".Image.">
    <factory
        id="Image"
        permission="Zope.ManageContent"
        title="Image"
        description="An Image" />
    <require
        permission="Zope.View"
        interface="Zope.App.OFS.Content.File.IFile.IReadFile" />
    <require
        permission="Zope.View"
        interface=".Image.IImage" />
    <require
        permission="Zope.ManageContent"
        interface="Zope.App.OFS.Content.File.IFile.IWriteFile" />
  </content>

The <factory> statement is almost identical.  I tried removing the
other differences in the <content> directive; these don't seem to make
a difference.

Looking in the Image class in the Image module, I see no further
clues.  I checked all the base classes and interfaces, and none of
them asserts the IFactory interface (or implements __call__); and even
if I add

    __class_implements__ = IFactory

to the JobList class, I still get the same error.

HEEEEEEEEEEEEEEEEEEEEEEEEEEELP!!!!!

--Guido van Rossum (home page: http://www.python.org/~guido/)