[Catalog-sig] PEP 345 Update

[Fred Drake]

On Mon, Aug 23, 2010 at 7:05 PM, P.J. Eby <pje at telecommunity.com> wrote:
> Hm.  Come to think of it, if all Conflicts is saying is, "I have modules of
> the same names as...", then couldn't any installer worth its salt figure
> this out for itself?  (Even PEP 376 already has a way to detect conflicting
> files before installing.)

This is not the only case that's interesting for Conflicts.  Certain
refactoring patterns can cause incompatibilities as well, and those
can be much harder to track down.

A new package which provides an interface that was once provided
elsewhere should generally be declared in conflict with older versions
of the package where the interface was originally provided (though not
in conflict with newer versions that pull the interface from the new
package).

This pattern has occurred frequently as the Zope community has worked
to reduce the dependencies on the zope.app packages, and there's been
no way to declare the conflicts.


  -Fred

--
Fred L. Drake, Jr.    <fdrake at gmail.com>
"A storm broke loose in my mind."  --Albert Einstein