Re: Proposed Modules, My Take

[Murray Cumming <murrayc murrayc com>]

On Wed, 2005-01-19 at 15:14 -0500, Sean Middleditch wrote:
> On Wed, 2005-01-19 at 21:07 +0100, Murray Cumming wrote:
> > On Wed, 2005-01-19 at 14:58 -0500, Sean Middleditch wrote:
> > > New versions must not break ABI.  While PyGTK itself does not break, it
> > > does heavily depend on the ABI of Python and that *does* break.  It's
> > > like saying it's alright if GTK+ is stable but glib can be unstable.
> > > Unless each release of GNOME has a standard Python version that must be
> > > available with that release, PyGTK would be breaking the spirit of the
> > > rules, if not the exact letter of the rules.
> > 
> > The application must specify the version of python. If not then the
> > application is choosing not to use a stable ABI.
> 
> Right.  The problem is that the application has no idea _which_ version
> of Python to specify.

The application developer knows by 
a) Reading the pygtk documentation, which says what versions of Python
work with pygtk. 
b) Seeing what works.

>   Two systems both running the same version of
> GNOME and the same version of PyGTK could have different versions of
> Python installed.

Yes, but it's up to the installer/package-management to make sure that
the correct version is there. If it's not, then the application will not
even start to run. That has nothing to do with pygtk.

>   Or one system could have two versions of Python, with
> only one of them having the PyGTK stuff.

Again, the installer/package-management must ensure that pygtk is
installed.

>   How does an application know
> which one to pick?  It knows it's developed against GNOME/PyGTK 2.10,
> and that's it.  If you specify, "GNOME 2.10 shall use Python 2.2," then
> the application author also knows which version of Python to specify and
> the app will work on all GNOME 2.10-compliant boxes.
> 
> If GNOME does not specify a version of Python than the entire existence
> of PyGTK in the Bindings becomes quite useless as a developer can't
> reliably use them.  Why even bother putting PyGTK in Bindings if
> developers can't rely on their app actually working?  They're still
> going to rely on individual distros, which is the exact same situation
> you had before putting PyGTK in Bindings.

You can't force distros to install python x.y, just because we say that
it's what GNOME wants them to install, much as I wish that distros cared
more about offering stable development platforms.

Different applications do use different versions of python. I don't
think there's any way for a non-broken distro to avoid managing those
dependencies properly.
 
-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com