[XML-SIG] Finding _xmlplus in Python 2.3a2

Martijn Faassen faassen@vet.uu.nl
Tue, 4 Mar 2003 15:55:00 +0100

Martin v. L=F6wis wrote:
> John J Lee <jjl@pobox.com> writes:
> > > I bring up the bug reporting simply because I don't recall anyone r=
> > > that PyXML broke their Python installation until now.  The cases yo=
u mention
> > > are abstract, but without concrete details, I cannot reply otherwis=
> > [...]
> >=20
> > That argument makes sense only when applied to a feature to be introd=
> > in the future, in which case we can't know what effect it will have
> > without considering concrete details.  This discussion is about a fea=
> > already introduced (the _xmlplus hack), which we *know* causes proble=
> > (unless you don't believe your users). =20
> I think this is the case: We don't believe the users.


Do you think I and others are arguing about this for fun or something?
Could any other users please pipe in here?

> I know Martijn
> has coworkers who are confused by this (in the sense that they are
> unaware of the entire issue, or have the wrong mental model). This, in
> itself, is no problem: Everybody of us certainly is unaware of some
> things, and has wrong mental models of other things.

This setup positively *encourages* the development of a wrong mental
model though. This causes the waste of time and energy.

> The question is whether this has created real problems, in the sense
> of wasted time and energy. Martijn has reported that it did, in the
> case of using undocumented API for constructing nodes. I find this
> example inconvincing, as the next Python release will make the same
> change, and thus break this code even without PyXML being installed

> I haven't heard any other practical examples of real problems caused
> by the current setup.

I've also mentioned the case of the developer being confused where
his sax parser was coming from. Doing the obvious thing leads you to the
wrong place; you go to the Python core library and look at the 'xml' pack=
there, and find a sax parser. After much frustration you find out that it
is somewhere else entirely. Another example is looking for 'xpath', and
while you find sax and all, you don't find it in the 'xml' package. How
odd? Where is it? Developers do look at source code, but they are faced
with a huge decoy in this situation if PyXML is installed.

These *are* real problems.