[Python-3000] PEP 3002 (Procedure for Backwards-Incompatible Changes)

[Steven Bethard]

On 4/27/06, Guido van Rossum <guido at python.org> wrote:
> I just read PEP 3002 and while I like most of what I see (thanks
> Steven Bethard!) there's one section that stands out as problematic.
[snip]
> Rather than a version of Python
> 3000, I suggest to add such warning code to Python 2.x, and not as a
> branch, but as a permanent feature (that is however only enabled by a
> command-line flag).

Yes, I think it definitely makes more sense to make the modifications
on 2.x.  I was hesitant to require integrating it into the main-line
Python 2.x code because I was worried about affecting performance. 
But of course with a command-line flag, that point is moot.  So
basically python3warn.py could be become "python -SOME_OPTION" where
SOME_OPTION would enable all the Python 3.0 checks.

So I guess the question then is what the option should enable.  Should
it try to implement the Python 3.0 behavior?  Or should it just warn
when the behavior is changed?  The former requires much more Python
3.0 code to be back-ported to Python 2.X, but would presumably give
much better error reporting.  I'd love to require that, but I'm afraid
of the work it would take.

Steve

P.S. I have commit access to the PEPs now, so I can update PEP 3002
with whatever we decide.
--
Grammar am for people who can't think for myself.
        --- Bucky Katt, Get Fuzzy