On 7/6/20 9:04 PM, Matthias Klose wrote: > Starting with Python 3.8, Python upstream changed to a time based yearly > release > schedule, targeting the first release of a major Python version (3.x) for > October of each year. For the transition to 3.8: > > - we add 3.8 as supported in November > - made 3.8 the default in March > - dropped 3.7 in April > > That's a little bit late looking at the Debian release schedule, so a little > speedup would be needed if we want to target the current Python release for > the > current Debian release. For 3.8 Ubuntu started to prepare the switch a bit > earlier, using the results for a better experience in Debian: > > - added 3.8 in mid October > - made 3.8 the default in mid December > > Technically it would be possible to do the defaults change before the Debian > freeze, however there's usually a tail of follow-up upstream releases required > to support a new major Python version, unless you opt for actively backporting > changes in various packages. Having the confidence, that the switch is > feasible > in another distro certainly helps doing the transition in Debian, however it > adds a delay. I don't think it's feasible to do the transition in > experimental > first, or doing a large test rebuild, because it requires keeping the whole > python stack in sync with testing/unstable. > > So what I'm proposing here is to aim to support 3.9 as early as possible as a > supported Python3 version, starting with the 3.9 upstream release, and fixing > stuff on the go. Then decide in November, if we can do the defaults change to > 3.9, or if we drop 3.9 again, or ship with two supported Python3 versions. > > Please note this will be a re-occuring situation with Python 3.11 and > bullseye+1, so we should find out how to handle this on a regular basis, > assuming that Debian release schedules won't change much.
3.9 was released last week and migrated to testing. I did a test rebuild with 3.9 as a supported Python3 version, however not for unstable, but for the current Ubuntu development version. Of course there is some version skew, but it should give an idea what still needs work. Bugs are filed at https://bugs.debian.org/cgi-bin/pkgreport.cgi?tag=python3.9;users=debian-python@lists.debian.org which definitely looks better than the addition of 3.8 last year. The PPAs used are based on groovy: https://launchpad.net/~pythoneers/+archive/ubuntu/python3.9 https://launchpad.net/~pythoneers/+archive/ubuntu/python3.9-fixes The first PPA just has no-change uploads, while the second one has some sourceful uploads. If you want to see some update in these PPAs, please ask Emmanuel Arias, Graham Inggs or myself. I'm planning to upload python3-defaults from experimental to unstable this Wednesday (Oct 14). We will see some days of instability as we are doing the binNMUs. Matthias
