[Jython-dev] Jython3 deliberate incompatibilities

[<fwi...@gm...>]

So I'm all but certain that 2013 is the year that we will actually
seriously start on a Jython3. This will be our one chance to
acceptably cause some backwards incompatibilities without too much
screaming. As with CPython, my intention is to have 2.7 stay well
maintained for a very long time to allow people to migrate as slowly
as they want.

So off the top of my head (and aside from all the obvious stuff to
follow CPython like dropping old style classes, etc):

* os.name should point to the actual os.name and not be "java". We
currently have an os._name that does this, but there are plenty of
ways to detect that we are on the JVM and so we don't need to take up
this spot with another check.

* package caching should be off by default. It is not supported by the
JVM and so has lots of corner cases where it does not work. It's very
useful, especially in interactive mode, so it should still be
available, just not on by default.

* remove the name checking that we do to allow passing things like
"actionPerformed" to be converted into EventListeners automatically -
see all swing from Jython tutorials for examples. We could probably
replace these with some decorators to be more explicit. I don't like
the magic this requires in PyJavaType.

* delete a bunch of old stuff like pawt.py.

I'm sure I will think of others. Thoughts? I won't be seriously
starting on Jython3 until 2.7.0 final is out, but I'm hoping that
won't be too terribly much longer.

-Frank