[Zope-PAS] PlonePAS error handling

[Wichert Akkerman]

The error handling in PlonePAS for user registration is quite
suboptimal: for all errors it just says "The login name you selected is
already in use or is not valid".

For plone.org this causes us to get users that are only created
partially: they are created in a LDAP database, but since
LDAPMultiPlugins does not implement mutable property sheets yet setting
the user properties fails. So we have a new user, but without any
properties. The PlonePAS registry.cpy catches the exception raised by
the property setting code and tells the user that the login name is
already in use or invalid, which is not true.

I'm not sure what the best way to fix this is. Either we should rollback
user creation if it fails halfway (tricky) or add some new exception
types so we can distinguish between fatal errors and non-fatal ones.

Wichert.

-- 
Wichert Akkerman <wichert at wiggy.net>    It is simple to make things.
http://www.wiggy.net/                   It is hard to make things simple.