[Python-Dev] public visibility of python-dev decisions "before it's too late"

"Martin v. Löwis" martin at v.loewis.de
Tue Mar 15 17:02:59 CET 2011


>> Python 2.6's API wasn't removed in 2.7. It remains available.
>
> But not in 3.2. And the new API appeared in 2.7.

No, it didn't. It first appeared in 3.1.

> That is a deprecation period of seven and a half months.

Not true. It's a deprecation period of 19 months and two
releases (3.1 and 2.7).

>> If you go from 2.7 to 3.2, you should expect things to break. That's
>> why the major version changed.
>
> And 3.1 to 3.2? There is no major version break there.

Right. So for things to be removed there, they have to be deprecated
first (and that's what happened).

>> For 3.x, as Reid points out, the API was deprecated in 3.1, so the
>> deprecation period was rather 19 months, not 7.
>
> Yes, but we are now in a period of parallell support for Python 2 and
> Python 3. So it doesn't work like that. We need to support both Python
> 2 and Python 3 at the same time. Therefore, the deprecation period was
> seven and a half month, because it was impossible to support the new
> API before, and impossible to support the new API after, if you need
> to support both Python 2 and Python 3.

If you actually had been supporting 2.x and 3.x in parallel for the last 
two years, you would have had a deprecation period of 19 months
and two releases. It's only if you are now migrating from 2 to 3
that you notice the breakage for the first time.

Regards,
Martin


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