[PyQt] Re: PyQt4 and Python 3.0

[Doug Bell]

Giovanni Bajo wrote:
> On 10/6/2008 7:27 PM, Joshua Kugler wrote:
>> Phil Thompson wrote:
>>
>>> On Fri, 3 Oct 2008 17:11:19 +0200, Detlev Offenbach
>>> <detlev at die-offenbachs.de> wrote:
>>>> Hi,
>>>>
>>>> will there be PyQt4 support for Python 3.0 once it goes final?
>>> Not straight away. I will take the opportunity to break backwards
>>> compatibility (eg. removing QVariant, QString, QChar, QByteArray etc), and
>>> those changes will be made over a period of time. So it may be a while
>>> before the API is stable enough for anything other than playing.
>>
>> Before you do that, please take into consideration Guido's advice:
>>
>> "Don't change your APIs incompatibly when porting to Py3k."
>>
>> http://www.artima.com/weblogs/viewpost.jsp?thread=227041
>
> I think the main collision here is that Guido is trying to help people  
> porting their applications to Python 3.0, while Phil seems to think that  
> it's better to rewrite them.
>
> IMO, PyQt shouldn't force its users to rewrite their code, especially  
> *not* tieing this to someone else's schedule (Qt4 release, Python 3  
> release). If an application grows unmaintainable, it will get eventually  
> rewritten but only when the programmer thinks so.
>
> Putting incompatible changes into PyQt and then telling people "*now*  
> it's time to rewrite" doesn't seem a good path forward to me.
>
> If there's agreement that we need to break backward compatibility on  
> PyQt (by changing the way QString or QVariant are mapped), I think it's  
> better to do so *independently* from any other changes (eg: Python 3).

I disagree, for several reasons:

  - Doing the changes separately means maintaining three separate
    versions of PyQt at once, taking more of Phil's time and promoting
    confusion.

  - Many Linux distros are unlikely to support all three versions at
    once.

  - The QString changes are somewhat related to Python 3's unicode
    string changes.  Both changes would affect the same portions of
    application code.

  - I agree that porting an application with both sets of changes is
    tougher than doing one change alone, but it's still easier to
    thoroughly test my applications once, rather than twice.

Doug.