Re: [Qemu-devel] [PATCH] configure: Require python3 >= 3.5

[Daniel P . Berrangé]

On Thu, May 09, 2019 at 11:36:04AM +0200, Kevin Wolf wrote:
> Am 09.05.2019 um 11:24 hat Kevin Wolf geschrieben:
> > Am 09.05.2019 um 07:45 hat Markus Armbruster geschrieben:
> > > Eduardo Habkost <address@hidden> writes:
> > > > diff --git a/.travis.yml b/.travis.yml
> > > > index 66448d99d6..0f6986b3f1 100644
> > > > --- a/.travis.yml
> > > > +++ b/.travis.yml
> > > > @@ -211,7 +211,7 @@ matrix:
> > > >          - CONFIG="--target-list=x86_64-softmmu"
> > > >        language: python
> > > >        python:
> > > > -        - "3.4"
> > > > +        - "3.5"
> > > >  
> > > >  
> > > >      - env:
> > > 
> > > Easily missed, good work.
> > > 
> > > My grep for similar references to Python versions we don't support found
> > > a few 2.x, x < 7.  Not this patch's problem, of course, but let me show
> > > them anyway:
> > 
> > I'm sure that we have a few more instances of Python 2 compatibility
> > code in qemu-iotests that can be removed after this is merged. These are
> > what I could find quickly, but there are probably more:
> > 
> >     242:        # Read one byte in a way compatible with Python 2
> >     iotests.py:        # Python < 3.4 needs to know not to add whitespace 
> > when pretty-printing:
> > 
> >     149:from __future__ import print_function
> >     165:from __future__ import print_function
> >     iotests.py:from __future__ import print_function
> >     nbd-fault-injector.py:from __future__ import print_function
> >     qcow2.py:from __future__ import print_function
> >     qed.py:from __future__ import print_function
> > 
> >     044:if sys.version_info.major == 2:
> >     163:if sys.version_info.major == 2:
> >     iotests.py:    if sys.version_info.major >= 3:
> >     iotests.py:        if sys.version_info.major >= 3:
> >     nbd-fault-injector.py:if sys.version_info.major >= 3:
> > 
> > I'm planning to take care of the qemu-iotests ones.
> > 
> > Also, with Python 3.5 as the new minimum, I think I'd like to add type
> > hints to iotests.py and possibly the qemu package (for QEMUQtestMachine
> > and friends). The syntax isn't as nice as if we could go straight to
> > 3.6, but still, finally some type checking instead of running into
> > stupid runtime bugs!
> 
> Ah, sorry, I was getting too excited there. We only deprecate 2.x now
> (and not even in this patch), but don't remove it yet. So I guess this
> will have to wait until next year.

If you're happy using one of the comment based hinting syntax, that
will work, or at least not break, with python 2

https://www.bernat.tech/the-state-of-type-hints-in-python/

Regards,
Daniel
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