Absolutely agree that it's way too early to think about changing to P3.
"I see no real benefits at this point and migrating the half a million lines of python and C extension code in calibre is not to be lightly undertaken. "
But, maybe it's worth considering a plan to migrate over the next 2 to 3 years?
Eventually 2.x and support will peter out.
Ebooks are exploding (in popularity) now, so Calibre is becoming a critical resource. I can feel the commercial pressures building.... Good luck with that...
Although in IT, I am newish to Python and am enjoying learning. I fancy doing my own news recipes.
Calibre is unique in offering a development environment embedded together with a working program.
If you want Calibre to continue for several years, then (although daunting) there should be some longer term strategy to move to Python 3.
http://docs.python.org/dev/howto/pyporting.html talks about writing Python 2/3 source-compatible code (I'm too new to see if this could work). But of course there is the difficult external libraries issue to consider. Some may never make it across (e.g. BeautifulSoup)?
However, if the process is begun at least each of the issues can be taken one at a time. Several Calibre contributors can assist in the migration. With a new Sub-Group and Forum over the next few years. It can be Python 2to3 in 2to3 years (you see what I did there.....
).
Anyhow, enough already. Just a thought about considering a longer term strategy and utilising/exploiting/encouraging/growing/improving the loyal Calibre following/contributors.
Cheers,
Peter.