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

[Daniel P . Berrangé]

On Sat, Oct 13, 2018 at 02:02:27AM -0300, Eduardo Habkost wrote:
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> 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.

Regards,
Daniel

[1] https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms
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