[Twisted-Python] Helping the Python 3 port

[exarkun at twistedmatrix.com]

On 09:04 am, jon at multani.info wrote:
>On Wed, May 08, 2013 at 05:40:56PM -0700, Glyph wrote:
>>
>>On May 8, 2013, at 4:03 PM, Jonathan Ballet <jon at multani.info> wrote:
>>
>> > On Wed, May 08, 2013 at 09:36:14AM -0600, Tom Prince wrote:
>> >> Have you seen https://twistedmatrix.com/trac/wiki/Plan/Python3 ?
>> >>
>> >> That is the plan for porting to python3.
>> >
>> > What about "importing" code from other librairies?
>> >
>> > I have this specific case where I need to support metaclass for both
>> > Python 2.x and Python 3.x which have different syntax (__metaclass__ 
>>and
>> > class XXX(.., metaclass=...)), which `six` addresses with a function
>> > called `with_metaclass()` [1]
>>
>>Within Twisted?  Which case is that?
>
>I was referring to twisted.python.reflect.PropertyAccessor which uses a
>metaclass to manage access to its properties. It is marked as 
>deprecated
>since Twisted 12.1.0, so I guess there still need to support it on both
>Python 2.x and Python 3, which is why I was looking for this
>compatibility layer.

Eh.  Strongly consider not porting deprecated things. :) 
PropertyAccessor could even be deleted for the next release, Twisted 
13.1 (this would be a relatively quick deprecation/removal cycle, but it 
just fits within the defined policy), if it is a maintenance burden - 
and forcing us to solve the metaclass issue sounds like a bit of a 
burden.

Jean-Paul
>> > Twisted is not depending on this kind of library, how those things
>> > should be deal with then? I can include this specific snippet (which 
>>is
>> > actually a two-liner)in t.python.compat but what about the license?
>>
>>Most of the logic in six is pretty trivial, and we already have our 
>>own Python-version-compatibility code (in twisted.python.compat) so 
>>thus far we have gone with just replicating whatever functionality we 
>>need.
>
>Granted, the code is trivial. So it's OK to replicate it in t.p.compat
>then? If there's a need for this code at all, of course :)
>
>Jonathan
>
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