Re: [Qemu-devel] Deprecation policy and build dependencies

[Eduardo Habkost]

On Wed, Jun 05, 2019 at 04:50:06PM +0100, Daniel P. Berrangé wrote:
> On Mon, Jun 03, 2019 at 02:26:49PM +0200, Markus Armbruster wrote:
> > John Snow <address@hidden> writes:
> > 
> > > On 5/31/19 3:24 PM, Eduardo Habkost wrote:
> > >> Long story short: I would really like to drop support for Python
> > >> 2 in QEMU 4.1.
> > 
> > The sooner, the better, as far as I'm concerned.
> > 
> > >> What exactly prevents us from doing this?  Does our deprecation
> > >> policy really apply to build dependencies?
> > >> 
> > >
> > > Normally I'd say it's only nice to also follow the depreciation policy
> > > for tooling as well to give people a chance to switch away, but with
> > > regards to Python2, I feel like we're in the clear to drop it for the
> > > first release that will happen after the Python2 doomsday clock.
> > >
> > > (So, probably 4.2.)
> > 
> > In addition to our feature deprecation policity, we have a "Supported
> > build platforms" policy (commit 45b47130f4b).  The most common holdback
> > is this one:
> > 
> >     For distributions with long-lifetime releases, the project will aim
> >     to support the most recent major version at all times. Support for
> >     the previous major version will be dropped 2 years after the new
> >     major version is released. For the purposes of identifying supported
> >     software versions, the project will look at RHEL, Debian, Ubuntu
> >     LTS, and SLES distros. Other long-lifetime distros will be assumed
> >     to ship similar software versions.
> > 
> > RHEL-7 has Python 3 only in EPEL.  RHEL-8 came out last month.  Unless
> > we interpret our policy to include EPEL, this means supporting Python 2
> > for some 16 months after upstream Python retires it.  My personal
> > opinion: nuts.
> 
> We've not said whether this refers to only base repos, or whether addon
> repos are accepted. IMHO, we are reasonably justified in saying RHEL-7
> as a build platform covers any repo provided by Red Hat, which would
> give us Python3 via software collections. I think it would be reasonable
> to also state it covers EPEL, since EPEL is such a commonly used repo
> with RHEL.
> 
> IOW, I don't think RHEL-7 support as a build platform blocks us from
> dropping py2. We merely need to tweak our build platforms doc to clarify
> our intent wrt add-on yum repos.

If we clarify the docs in QEMU 4.1, is there anything that
prevents us from removing Python 2 support in QEMU 4.1 too?

-- 
Eduardo