[Python-Dev] [Python-3000] Warning for 2.6 and greater

[Anthony Baxter]

On Thursday 11 January 2007 05:13, Raymond Hettinger wrote:
> It is my strong preference that we not go down this path.
> Instead, the 2.6 vs 3.0 difference analysis should go in an
> external lint utility.

I don't see how an external utility can possibly catch everything 
that's going to break - it's going to be much much easier to catch 
things like use of has_key and the like from inside the 
interpreter. Additionally, catching things like C code extensions 
using a slot or a method or a function that's going away is just 
not going to be possible otherwise.

> The Py2.x series may live-on for some time and should do so
> as if Py3.x did not exist.  Burdening the 2.x code with loads
> of warnings will only clutter the source code and make
> maintenance more difficult.  There may also be some performance
> impact.

If it's a single check of a C int, the performance impact will be 
minimal. I agree that 2.x will live for a long time - but unless we 
provide the best possible upgrade path, we will be stuck 
maintaining both 2.x and 3.x for ever.

Additionally, without a 2.x<->3.x upgrade path 3.x is essentially a 
new language, having to build a new userbase from scratch. Worse 
yet, 2.x will suffer as people have the perception "Python 2? 
That's a dead/abandoned language"

> We should resolve that Py2.6 remain as clean as possible
> and that Py3.0 be kept in its own world.  Forging a new
> blade does not have to entail dulling the trusty old blade.

I completely disagree here. We cannot simply ignore 3.0 in the 2.x 
series. We need to provide (as much as possible) an upgrade path 
for people who write and use code in the language.

Anthony
-- 
Anthony Baxter     <anthony at interlink.com.au>
It's never too late to have a happy childhood.