[Python-Dev] Bug #537450 Improper object initialization for type.__new__

[Guido van Rossum]

> Python 2.2.2 beta 1 is coming out, and I was hoping to float a final
> request to have the fix for bug #537450 applied to the 2.2 maint
> branch (it is a trivial backport, since the 2.3 patch applies just
> fine).  A back-port was originally passed over, because it changes
> semantics from Python 2.2.1.  I argue that the changed semantics are
> desirable and constitute a clear bug fix, which closes holes that
> can allow very obscure errors.  It would be very surprising to me if
> this change breaks any extant code, since it is virtually impossible
> to take meaningful or safe advantage of the original semantics.
[...]
> I assert that no sensible developer would ever write code that
> relied on the pre-2.3 CVS semantics.  I've done a survey of much of
> the meta-class code posted to or discussed on Python-dev and
> comp.lang.python, and none rely on this behavior.  Plus, even if
> they did, we have already decided they will have to change it when
> 2.3 comes out.
> 
> If you are not entirely convinced by the above argument, please
> consider a compromise solution: put the fix in for 2.2.1 Beta 1.  If
> anyone has complaints based on extant code, then we can always back
> it out for Beta 2, or the final release.

OK, that's a deal.  It's in 2.2.2b1.  If there are problems with it I
may back it out before 2.2.2final though.

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