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[Python-Dev] __new__ deprecation

Guido van Rossum guido at python.org
Wed Feb 13 23:47:53 CET 2008 
The message means just what it says. :-) There's no point in calling
object.__new__() with more than a class parameter, and any code that
did so was just dumping those args into a black hole.

The only time when it makes sense for object.__new__() to ignore extra
arguments is when it's not being overridden, but __init__ *is* being
overridden -- then you have a completely default __new__ and the
checking of constructor arguments is relegated to __init__.

The purpose of all this is to catch the error in a call like
object(42) which (again) passes an argument that is not used. This is
often a symptom of a bug in your program.

--Guido

On Feb 13, 2008 12:19 PM, Jeroen Ruigrok van der Werven
<asmodai at in-nomine.org> wrote:
> -On [20080213 21:02], Guido van Rossum (guido at python.org) wrote:
> >What __new__ deprecation warning?
>
> Yes, sorry, I realized after sending that it might be a bit obtuse.
>
> With 2.6:
>
> DeprecationWarning: object.__new__() takes no parameters
>   return object.__new__(cls, uri)
>
> --
> Jeroen Ruigrok van der Werven <asmodai(-at-)in-nomine.org> / asmodai
> $B%$%'%k!<%s(B $B%i%&%U%m%C%/(B $B%t%!%s(B $B%G%k(B $B%&%'%k%t%'%s(B
> http://www.in-nomine.org/ | http://www.rangaku.org/
> I am the impossibility...
>



-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)
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