Re: [Qemu-devel] [PULL 0/8] Python queue, 2019-06-07

[Kevin Wolf <kwolf@redhat.com>]

Am 11.06.2019 um 19:12 hat Eduardo Habkost geschrieben:
> On Tue, Jun 11, 2019 at 05:07:55PM +0100, Peter Maydell wrote:
> > On Tue, 11 Jun 2019 at 17:03, Eduardo Habkost <ehabkost@redhat.com> wrote:
> > >
> > > On Tue, Jun 11, 2019 at 04:50:34PM +0100, Peter Maydell wrote:
> > > > On Mon, 10 Jun 2019 at 13:58, Peter Maydell <peter.maydell@linaro.org> wrote:
> > > > > Hi. This fails to build on one of my buildtest machines:
> > > > >
> > > > > ERROR: Cannot use 'python3', Python 2 >= 2.7 or Python 3 >= 3.5 is required.
> > > > >        Use --python=/path/to/python to specify a supported Python.
> > > > >
> > > > > The machine has python 2.7.6 and 3.4.3. (It's an Ubuntu trusty
> > > > > box; it's one of the gcc compile farm machines so upgrades to its
> > > > > OS are not really under my control.)
> > > >
> > > > Rereading this, I realise that either the check or the error
> > > > message is wrong here. The machine has 2.7.6, which satisfies
> > > > "python 2 >= 2.7", so we should be OK to build. The bug
> > > > seems to be that we say "prefer python3 over plain python
> > > > on python2" early, but don't revisit that decision if the
> > > > python3 we found isn't actually good enough for us.
> > >
> > > Right.  The error message is technically correct, but misleading.
> > > python3 is too old, but python2 would work.
> > >
> > > We can make configure not use python3 by default if it's too old,
> > > and fall back to python2 in this case.
> > 
> > Sounds good. Since I have now managed to get my alternate
> > aarch64 box set up, how about I apply this pullreq and you
> > send a followup patch which does the fallback to python/python2 ?
> 
> I will remove the python2/python3 patches and send a new pull
> request.

What is the plan forward with this? Are the patches dropped for good?

I think the plan was to drop Python 2 after QEMU 4.2, and then it
becomes really relevant what our minimum Python 3 version is. We've just
had another Python version discussion in the context of iotests (John
suggested using function annotations, but these are >= 3.5 only).

Also, the fallback to Python 2 obviously makes no sense any more then,
so maybe it's not that important to add for a single QEMU release?

As Peter seems to have indicated above that he found a replacement for
the test machine with an OS that isn't out of support, can we just
revive this patch as it is?

Kevin