handle ViewNotCallableError as 404

[djay]

This can happen in Plone with spam/pentests hitting @@images without a further traversal.

ViewNotCallableError: __call__
  File "ZPublisher/WSGIPublisher.py", line 181, in transaction_pubevents
    yield
  File "ZPublisher/WSGIPublisher.py", line 391, in publish_module
    response = _publish(request, new_mod_info)
  File "ZPublisher/WSGIPublisher.py", line 269, in publish
    obj = request.traverse(path, validated_hook=validate_user)
  File "ZPublisher/BaseRequest.py", line 483, in traverse
    object, default_path = adapter.browserDefault(self)
  File "/app/eggs/zope.browserpage-4.4.0-py3.9.egg/zope/browserpage/metaconfigure.py", line 434, in browserDefault
    meth = getattr(self, attr)
  File "app/eggs/Zope-5.8.5-py3.9.egg/Products/Five/browser/metaconfigure.py", line 448, in __call__
    raise ViewNotCallableError('__call__')

[perrinjerome]

Would another approach of making ViewNotCallableError a subclass of zExceptions.NotFound work without any change to BaseRequest ? I was thinking that returning not found when a NotImplementedError is raised might be surprising during development.

[dataflake]

I have no idea how disruptive that may be.

[perrinjerome]

I don't know either, maybe it does not even translates to 404 response here, I suggested this as it seemed a possible easier implementation. In any case, the current approach seems OK.

[dataflake]

Go ahead and merge