How to guard against bugs like this one?

[kj]

Let me preface everything by thanking you and all those who
replied for their comments.

I have only one follow-up question (or rather, set of related
questions) that I'm very keen about, plus a bit of a vent at the
end.

In <pan.2010.02.02.03.28.54 at REMOVE.THIS.cybersource.com.au> Steven D'Aprano <steven at REMOVE.THIS.cybersource.com.au> writes:

>As for fixing it, unfortunately it's not quite so simple to fix without 
>breaking backwards-compatibility. The opportunity to do so for Python 3.0 
>was missed.

This last point is to me the most befuddling of all.  Does anyone
know why this opportunity was missed for 3.0?  Anyone out there
with the inside scoop on this?  Was the fixing of this problem
discussed in some PEP or some mailing list thread?  (I've tried
Googling this but did not hit on the right keywords to bring up
the deliberations I'm looking for.)

~k

[NB: as I said before, what follows begins to slide into a vent,
and is quite unimportant; I've left it, for whatever grain of truth
it may contain, as an grossly overgrown PS; feel free to ignore
it, I'm *by far* most interested in the question stated in the
paragraph right above, because it will give me, I hope, a better
sense of where the biggest obstacles to fixing this problem lie.]

P.S. Yes, I see the backwards-compatibility problem, but that's
what rolling out a whole new versions is good for; it's a bit of
a fresh start.  I remember hearing GvR's Google Talk on the coming
Python 3, which was still in the works then, and being struck by
the sheer *modesty* of the proposed changes (while the developers
of the mythical Perl6 seemed to be on a quest for transcendence to
a Higher Plane of Programming, as they still are).  In particular
the business with print -> print() seemed truly bizarre to me: this
is a change that will break a *huge* volume of code, and yet,
judging by the rationale given for it, the change solves what are,
IMHO, a relatively minor annoyances.  Python's old print statement
is, I think, at most a tiny little zit invisible to all but those
obsessed with absolute perfection.  And I can't imagine that whatever
would be required to fix Python's import system could break more
code than redefining the rules for a workhorse like print.

In contrast, the Python import problem is a ticking bomb potentially
affecting all code that imports other modules.  All that needs to
happen is that, in a future release of Python, some new standard
module emerges (like numbers.py emerged in 2.6), and this module
is imported by some module your code imports.  Boom!  Note that it
was only coincidental that the bug I reported in this thread occurred
in a script I wrote recently.  I could have written both scripts
before 2.6 was released, and the new numbers.py along with it;
barring the uncanny clairvoyance of some responders, there would
have been, at the time, absolutely no plausible reason for not
naming one of the two scripts numbers.py.

To the argument that the import system can't be easily fixed because
it breaks existing code, one can reply that the *current* import
system already breaks existing code, as illustrated by the example
I've given in this thread: this could have easily been old pre-2.6
code that got broken just because Python decided to add numbers.py
to the distribution.  (Yes, Python can't guarantee that the names
of new standard modules won't clash with the names of existing
local modules, but this is true for Perl as well, and due to Perl's
module import scheme (and naming conventions), a scenario like the
one I presented in this thread would have been astronomically
improbable.  The Perl example shows that the design of the module
import scheme and naming conventions for standard modules can go
a long way to minimize the consequences of this unavoidable potential
for future name clashes.)