Peter Maydell <peter.mayd...@linaro.org> writes: > On Wed, 16 Sep 2020 at 08:43, Markus Armbruster <arm...@redhat.com> wrote: >> We require Python 3.5. It will reach its "end of life" at the end of >> September 2020[*]. Any reason not to require 3.6 for 5.2? qemu-iotests >> already does for its Python parts. > > I think these things really ought to start with the converse question: > what is the important new thing that 3.6 brings to the table that > makes it worth moving our minimum requirement forward ?
I'm chiefly after PEP 526 "Syntax for Variable Annotations" for much saner type hints. John's "[PATCH 00/37] qapi: static typing conversion pt1" already uses it, because not using it results in illegible code. Nice to have: PEP 498 "Literal String Interpolation" may let us improve QAPI code geneator readability. I haven't tried, yet. <https://www.python.org/dev/peps/pep-0494/#features-for-3-6> has the full list of new features. > If our code still works on 3.5 and there's nothing we really want to > do to the code that would be awkward to do without insisting on > 3.6, why should we irritate users by arbitrarily bumping the version > requirement ? > > Also as Dan notes upstream's EOL policies aren't very relevant, > because our policy is based on what distros ship. > > My broader point of view: C does not have any kind of infrastructure > like Rust's cargo or node's npm that makes it easy for a project to > say "we depend on these versions of these other packages" and > have them be satisified in a fairly painless-to-the-end-user/distro > way. So I prefer to take the approach of being as conservative as > possible about what we depend on, because the alternative tends > to be either pain for the person trying to compile QEMU (when they > have to scrabble around finding and building dependencies they > don't have conveniently to hand) or pain for us (when we have > to ship a dependency as a submodule). The default should be > "leave the version dependency where it is", not "bump the version > dependency as soon as we can". Understood. Anyone writing Python code in QEMU has paid a price for this policy. I certainly did. I'm okay with that as long as it helps more than it hurts. Lack of sane type hints is hurting QAPI developement. I believe requiring 3.6 will hurt QEMU less than hobbled QAPI development.
