From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51704) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gKjew-00024N-7M for qemu-devel@nongnu.org; Thu, 08 Nov 2018 07:43:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gKjev-0007G0-7W for qemu-devel@nongnu.org; Thu, 08 Nov 2018 07:43:42 -0500 From: Markus Armbruster References: <20181031003120.26771-1-ehabkost@redhat.com> <20181031003120.26771-12-ehabkost@redhat.com> <20181106141302.GP12503@habkost.net> <87efbxxw1c.fsf@dusky.pond.sub.org> <8ecdbb0e-aaf8-ddc5-6442-87977585d9d8@redhat.com> <87y3a4ot3g.fsf@dusky.pond.sub.org> Date: Thu, 08 Nov 2018 13:43:28 +0100 In-Reply-To: ("Philippe =?utf-8?Q?Mathieu-Daud=C3=A9=22's?= message of "Thu, 8 Nov 2018 10:11:38 +0100") Message-ID: <8736sboi33.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] tests: Fix Python 3 detection on older GNU make versions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Cc: Kevin Wolf , Peter Maydell , Fam Zheng , Eduardo Habkost , Qemu-block , Alex =?utf-8?Q?Benn=C3=A9e?= , QEMU Developers , Max Reitz , Cleber Rosa , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Philippe Mathieu-Daud=C3=A9 writes: > Hi Markus, > > > Le jeu. 8 nov. 2018 09:46, Markus Armbruster a =C3=A9= crit : > >> Cleber Rosa writes: >> >> > On 11/7/18 1:05 AM, Markus Armbruster wrote: [...] >> >> PEP 394 recommends software distributions install Python 3 into the >> >> default path as python3, and users use that instead of python, except >> >> for programs that are source compatible with both 2 and 3. So, is >> >> finding out whether python is a Python 3 really appropriate? Why can= 't >> >> we just use python3 and be done with it? >> >> >> > >> > I mentioned that before, when you pointed out the issue you fix here, >> > that configure may be the best place to get the Python version (not on= ly >> > the major version) and make it available elsewhere. Even if not used >> > for other purposes, it is IMO important information to show on the >> > resulting "configure" output. >> > >> > I'm sending patches to do that in a few. >> > >> >> If we can't: isn't this a configure problem? >> >> >> > >> > I believe adhering to PEP394 is a good thing, but even that document >> > recognizes that the real world is not a perfect place: "however, end >> > users should be aware that python refers to python3 on at least Arch >> > Linux". And it only covers *nix systems, so if we hope to care for >> > non-*nix systems, we have to check the Python version manually. >> > >> > So, I guess the safest approach from QEMU's side is to check for the >> > version indeed. >> >> If somebody can point to a system people still use where python3 doesn't >> get you a Python 3, but python does, catering for such (crappy) systems >> in configure makes sense. Until then, it's a waste of brain waves and >> configure run time. >> >> PEP 394 mentions Arch Linux. It's been seven years. What's the most >> recent version of Arch Linux that's still crappy in this regard? >> > > Arch doesn't provide python2 by default, thus python points to python3. That's non-crappy as long as python3 also exists, as PEP 394 recommends. Does it? > I think what's crappy is scripts expecting python to be python2. No argument.