[XML-SIG] Re: Finding _xmlplus in Python 2.3a2

Martijn Faassen faassen@vet.uu.nl
Mon, 3 Mar 2003 11:38:47 +0100

Martin v. L=F6wis wrote:
> Martijn Faassen <faassen@vet.uu.nl> writes:
> > Or even weirder, you upgrade your Python but you
> > also have PyXML installed for it (or install it later), and now it ma=
y be
> > magically *degraded*.
> I'll write a separate response, but: This cannot happen. If you
> install a new Python release, it won't take over an existing PyXML
> installation - you will have to explicitly install PyXML again for
> that Python installation.
> Installing PyXML won't downgrade you XML libraries: The _xmlplus
> version check is designed to prevent that.

Ah right, I hadn't thought about that. (which is evidence the interaction
is actually more complicated; now I need to somehow magically know what
XML version my core Python version has and how this interacts with PyXML

> > No, I have witnessed several developers using this software not under=
> > the arrangment, which is obscure and confusing. In addition there are=
> > users who get confused as well. Dependency management would be a lot =
> > straightforward for everyone if PyXML had its own top level namespace.
> That would break a lot of existing code.

Of course, but it would also simplify matters in development and
deployment. And I hope there can be some discussion of migration=20
strategies. You could for instance abandon the scheme in the next
PyXML release, keep _xmlplus of the previous one installed if it's
there, and point out to people that in order to use PyXML from now on
they have to explicitly refer to the pyxml namespace. You could even
provide a migration hack where people can explicitly enable pyxml to
be picked up in the traditional way.