[Zope-dev] zope.security dependency on zope.exceptions

[Tres Seaver]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Fabio Tranchitella wrote:
> Happy New Year to everybody,
> 
> I'm working to isolate a core set of ZTK packages which are independent
> from Zope and reusable outside the Zope community. One of them is
> zope.security, which can be used (and it is useful, indeed) with non-zope
> frameworks too.
> 
> While doing it, I'm trying to remove dependencies which are zope-specific,
> to minimize the overhead for developers who are using the whole zope stack
> (like me :)).

I have such a subset in mind myself, which I call the "bicycle seat
repair kit":

 - zope.interface
 - zope.coponent
 - zope.configuration
 - their dependencies.

> zope.security depends on zope.exceptions because it imports this symbol in
> zope.security.checker:
> 
>     from zope.exceptions import DuplicationError
> 
> zope.exceptions defines DuplicationError as:
> 
>     class IDuplicationError(Interface):
>         pass
> 
>     class DuplicationError(Exception):
>         """A duplicate registration was attempted"""
>         implements(IDuplicationError)
> 
> The zope.exceptions package contains "exception interfaces and
> implementations which are so general purpose that they don't belong in Zope
> application-specific packages.", as stated by the README.
> 
> I propose to make the remove the dependency between zope.security and
> zope.exceptions with a conditional import:
> 
>  * if zope.exceptions is available, use DuplicationError from it;
> 
>  * if it is not available, define a zope.security-specific DuplicationError
>    (which inherits from ValueError, maybe).
> 
> As using zope.exceptions only make sense if you are checking the exception
> type importing its interface from the zope.exceptions package, and thus
> depending on it, I see no risk in such a change.
> 
> Thoughts? Comments?

+1.  I wouldn't have thought zope.security useful elsewhere, but I take
it you are using it in applications which don't use the rest of the stack.


Tres.
- --
===================================================================
Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEARECAAYFAktD2N8ACgkQ+gerLs4ltQ7G0wCfVu0KZAZ5xzUXarXUO2nT6bIm
LXQAoIYxT6lKDGgGeCq/ec7Xh+X+4WBo
=dErh
-----END PGP SIGNATURE-----