Re: [Qemu-devel] [RFC] Require Python 3 for building QEMU

[Peter Maydell <peter.maydell@linaro.org>]

On 15 October 2018 at 10:32, Daniel P. Berrangé <berrange@redhat.com> wrote:
> On Sat, Oct 13, 2018 at 02:02:27AM -0300, Eduardo Habkost wrote:
>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>> ---
>> I'd like to do this in QEMU 3.1.  I think it's time to drop
>> support for old systems that have only Python 2.
>>
>> We still have a few scripts that are not required for building
>> QEMU that still work only with Python 2 (iotests being the most
>> relevant set).  Requiring Python 3 for building QEMU won't
>> prevent people from using those scripts with Python 2 until they
>> are finally ported.
>
> I think it is premature & unecessary to do this. We just got QEMU building
> with dual Python2/3 in 3.0 to give people leeway in the migration path to
> a fully v3 future. The code to support building 2/3 in parallel is not
> imposing a unreasonable maint burden. Dropping py2 suport would have
> negligible impact on the code, as there's no v3-only features we have
> used. IOW, I don't think there's a compelling reason to rush into forcing
> users onto v3.
>
> If we want to drop py2, we should give people a warning of such a planned
> change, especially since some of our targetted host OS[1] don't even
> include a py3 as standard without acquiring extra add-on repos. Devs in
> a typical corporate env will not have the freedom to install such extra
> repos on their machines.

I agree. I also think that dropping python 2 support before we've
even converted all our python scripts to handle python 3 is the
wrong order to do things. People interested in moving forward with
the transition to python-3-only should start by making sure everything
we have works with python 3...

thanks
-- PMM