[Zope3-dev] Re: pydoc troubles

[Baiju M]

On 9/8/06, Michael Haubenwallner <michael at d2m.at> wrote:
> Michael Haubenwallner wrote:
> > Anyway, using the right paths i get back to where i initially started:
> > the package information is not displayed for several packages
> >
> > pydoc displays package information on zope.proxy, zope.component,
> > zope.interface for example like this:
> >
> > -----
> > Help on package zope.component in zope:
> >
> > zope.component = <module 'zope.component' from
> > '/path/to/Zope3/src/zope/component/__init__.pyc'
> > -----
> >
> > I'd really like to make Zope3 code look good and complete from pydoc.
> >
>
> Actually what makes pydoc display this instead of the package listing is
> an AttributeError thrown:
> AttributeError: 'Provides' object has no attribute '__name__'
>
> Adding the name attribute to zope.interface.declarations.Provides
> makes the Exception go away and renders the pydoc docs correctly.
>
> I wonder if this is the right way to go or if the __name__ attribute was
> omitted by design.

If Python's `isclass` function in `inspect` module is correct (I think, it is)
then instance of `zope.interface.declarations.ProvidesClass` should not have
`__bases__` attribute.

This is the `isclass` function from `inspect` module:

  def isclass(object):
      """Return true if the object is a class.

      Class objects provide these attributes:
          __doc__         documentation string
          __module__      name of module in which this class was defined"""
      return isinstance(object, types.ClassType) or hasattr(object, '__bases__')

This `inspect` module is used in `pydoc` to determine types of objects.

So, pydoc treats instance of `zope.interface.declarations.ProvidesClass`
as a class, and try to access `__name__` attribute, then it fails.

Here is a pseudo test case:

  >>> from zope.interface.declarations import ProvidesClass
  >>> ProvidesClass(()).__bases__
  ()
  >>> class C(object): pass
  ...
  >>> C().__bases__
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
  AttributeError: 'C' object has no attribute '__bases__'

Regards,
Baiju M