[Python-Dev] Deprecation warnings in Python 2.7

[Florent Xicluna]

Hello,

I would like to open a discussion on the meaning of deprecation warnings in 2.7.
I assume, but I may be wrong, that 2.7 will be the last version in the 2.x
branch.  With this assumption, we should not find many things deprecated in 2.7
final.

On the other hand, the list of py3k deprecation warnings is increasing a lot.
And more users will probably start to move from 2.7 to the 3.1 release.

While working on ticket #7092 and #7849, we started to discuss some proposals
to simplify the deprecation warnings for 2.7.

We discussed these 2 proposals:

 1) in 2.6 there's no distinction between py3k and normal deprecations: they
    share the same category, DeprecationWarning.  The "-3" switch enables the
    py3k DeprecationWarning and SyntaxWarning.
    Do we need to introduce a subclass Py3kDeprecationWarning in 2.7?  It will
    make it easier to separate both kinds of deprecations (2.x and 3.x), and
    to filter them.
    
 2) a different idea is to deprecate the "-3" switch and consider all py3k
    deprecations as normal deprecations.  They will be hidden by default
    thanks to #7309.  Since there's no future for the 2.x branch, it seems
    normal to consider the migration from 2.7 to 3.1 and show these warnings
    when the developer uses "-Wd" switch.

What do you expect as DeprecationWarning in 2.7?

I will post a list of the DeprecationWarnings in the python trunk, in a
followup message, for a review, and to help the discussion.

Best regards,

-- 
Florent Xicluna