A proposal from Javier Jardon has been published a few days ago on Gnome live about porting Gnome to Python 3. As of 2010, Python 2.7 is the last 2.x version that is available.
Python 3 is the future of the language and all the new features and additions concern the 3 branch, while 2.x is considered stagnated in term of development.
As most of applications and OSes are using Python 2.x and the compatibility with version 3 is not very good, it is still not very clear when the porting should begin, but this is something that is definitely going to happen sooner or later. Gnome has proven to be the pioneer in adopting new technologies so why not go for it once again?
As Javier explains:
Its much better for us to support only one version of the Python language.
Also, we can take advantage of the latest improvements in the language itself and make a cleanup of the affected modules when we are porting to the new code. We want to be closer to all upstreams, and all the current Python development is in the 3.x series
Right now the situation is pretty much incunabular with only one application that is Orca, and seven more modules using Python 3, so there is a lot of work to be done.
Let’s see if the developers will decide to do this on the road to Gnome 3.8. This would be another nice detail that under the hood is not a detail at all…