[Zope-CMF] [dev] Unauthorized confusion and Zope 2.4 compatibility

[Yuppie]

Hi!


Zope has two different Unauthorized exceptions: 
AccessControl.Unauthorized is a subclass of zExceptions.Unauthorized. 
The usage of the two exceptions is more or less random.

See also this mail and thread: 
<http://mail.zope.org/pipermail/zope-coders/2003-November/004346.html>

This issue isn't resolved in Zope, but even if it would be resolved in 
Zope 2.7 we have to find a solution that works with older Zope versions.


I propose to use zExceptions.Unauthorized to catch Unauthorized (catches 
both) and AccessControl.Unauthorized to raise Unauthorized (can be 
catched by both).

CMFCoreExceptions.CMFUnauthorizedError is already a subclass of 
AccessControl.Unauthorized and could be used to raise Unauthorized.

CMFCoreExceptions.Unauthorized could become an alias of 
zExceptions.Unauthorized.

Any better ideas?


The issue becomes more complicated if we try to be Zope 2.4 compatible: 
In Zope 2.4 zExceptions.Unauthorized didn't exist and 
AccessControl.Unauthorized was a string exception.

Is there any good reason to maintain Zope 2.4 compatibility?

INSTALL.txt says:

   Requirements
     - Zope v. 2.5 and later
       o Note:  Zope v. 2.4.3 *may* work, but is no longer a supported
         version.

I don't like to care any longer about Zope 2.4. I propose to remove that 
note and import zExceptions.Unauthorized without handling an ImportError.

Comments are welcome!


Cheers,
	Yuppie