[Zope-PAS] maxlistusers and OverflowError

[Willi Langenberger]

Hi!


The class PluggableAuthService defines "maxlistusers = -1":

  class PluggableAuthService( Folder, Cacheable ):
      [...]
      maxlistusers = -1   # Don't allow local role form to try to list us!

However, the RoleManager method "get_valid_userids", has the following
lines in it:

  Zope-2.7.2/lib/python/AccessControl/Role.py:

  class RoleManager(ExtensionClass.Base, PermissionMapping.RoleManager):
      [...]

      def get_valid_userids(self):
          item=self
          dict={}
          _notfound = []
          while 1:
              aclu = getattr(aq_base(item), '__allow_groups__', _notfound)
              if aclu is not _notfound:
                  mlu = getattr(aclu, 'maxlistusers', _notfound)
                  if type(mlu) != type(1): mlu = DEFAULTMAXLISTUSERS
                  if mlu < 0: raise OverflowError
                     ^^^^^^^^

Thus, maxlistusers < 0 raises an OverflowError.

This seems to bite us, when we try to install Silva. Selecting "Silva
Root" from the Product Add Menu, gives the following errorpage:

  Exception Type    OverflowError
  Exception Value

  Traceback (innermost last):
    Module ZPublisher.Publish, line 98, in publish
    Module ZPublisher.mapply, line 88, in mapply
    Module ZPublisher.Publish, line 39, in call_object
    Module Products.Silva.Root, line 317, in manage_addRoot
    Module Products.Silva.install, line 96, in installFromScratch
    Module Products.Silva.install, line 625, in installSilvaDocument
    Module Products.Silva.Security, line 260, in sec_update_last_author_info
    Module Products.Silva.Security, line 227, in sec_get_member
    Module Products.Silva.SimpleMembership, line 191, in get_cached_member
    Module Products.Silva.SimpleMembership, line 177, in get_member
    Module Products.Silva.SimpleMembership, line 172, in is_user
    Module AccessControl.Role, line 314, in get_valid_userids
  OverflowError

So my questions are:

  - what is the rationale behind setting maxlistusers to -1?

  - could this prevent some (user-listing) functions from working
    correctily?

  - or, is it Silva's fault (should it catch the OverflowError)?

We got it to work by setting maxlistusers to 20, but i doubt this is
the right way to fix it...


Cheers,


\wlang{}

-- 
Willi.Langenberger at wu-wien.ac.at                Fax: +43/1/31336/9207
Zentrum fuer Informatikdienste, Wirtschaftsuniversitaet Wien, Austria