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Violators will be prosecuted for from ; Mon, 15 Oct 2018 19:19:25 +0100 References: <20181013050227.17022-1-ehabkost@redhat.com> <20181015093243.GE6785@redhat.com> <20181015101309.GD10459@localhost.localdomain> <87woqjw4o3.fsf@dusky.pond.sub.org> From: Christian Borntraeger Date: Mon, 15 Oct 2018 20:19:18 +0200 MIME-Version: 1.0 In-Reply-To: <87woqjw4o3.fsf@dusky.pond.sub.org> Content-Language: en-US Message-Id: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC] Require Python 3 for building QEMU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster , Kevin Wolf Cc: Peter Maydell , Fam Zheng , Eduardo Habkost , Qemu-block , QEMU Developers , Max Reitz , Stefan Hajnoczi , Cleber Rosa , =?UTF-8?Q?Alex_Benn=c3=a9e?= , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= On 10/15/2018 06:33 PM, Markus Armbruster wrote: > Kevin Wolf writes: >=20 >> Am 15.10.2018 um 12:02 hat Peter Maydell geschrieben: >>> On 15 October 2018 at 10:32, Daniel P. Berrang=C3=A9 wrote: >>>> On Sat, Oct 13, 2018 at 02:02:27AM -0300, Eduardo Habkost wrote: >>>>> Signed-off-by: Eduardo Habkost >>>>> --- >>>>> 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 bu= ilding >>>> with dual Python2/3 in 3.0 to give people leeway in the migration pa= th to >>>> a fully v3 future. The code to support building 2/3 in parallel is n= ot >>>> imposing a unreasonable maint burden. Dropping py2 suport would have >>>> negligible impact on the code, as there's no v3-only features we hav= e >>>> used. IOW, I don't think there's a compelling reason to rush into fo= rcing >>>> users onto v3. >>>> >>>> If we want to drop py2, we should give people a warning of such a pl= anned >>>> 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 ex= tra >>>> 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 everythin= g >>> we have works with python 3... >> >> It's easier to port stuff to Python 3 though than making them work wit= h >> both. I think Eduardo's RFC is in part motivated by a patch from >> Philippe that converted something in iotests to work with Python 3, >> passed review and then turned out to break Python 2. >=20 > Seconded. This is not about the cost of maintaining existing > compatibility gunk, it's about the extra effort to first get the > remainder to work with 2 and 3, only to throw away 2 a few months later. >=20 > I propose we permit ourselves to port stuff that isn't essential to > building QEMU straight to 3 instead. This includes iotests. >=20 >> Having to test every iotests patch twice with different Python version= s >> isn't something I would like to do for extended periods of time. >=20 > It's worth doing only if the benefits of doing it outweigh the costs. = I > don't think they do. FWIW, I do not care about python 2 vs 3. I just want to emphasize that I=20 consider the qemu iotest a very valuable part of the qemu test suite as i= t has detected a lot of regressions over the past years. So as long as we k= eep that running I am fine. >=20