Hello Ben, What happens if one builds only python3 and the interpreter changes from 3.8 to 3.9. The stuff installed under ..python38/site-packages should then not be accessible anymore? Schöne Grüße Axel -- Written from cell phone - excuses for typos Am 19. Januar 2021 22:15:57 MEZ schrieb Ben Greiner :

Hello List subscribers,

people have been complaining that they missed some important messages because the previous mails were "buried" as answers in some sub threads and understandably not everyone reads every thread due to high mail volume. So here is some more volume for you, again posting to 3 mailinglists. Top post without any reference to other mails.

A major change of the python-rpm-macros and matching prjconf definitions has been introduced to Factory last Friday. Now is the time to fix your python-foo packages, or specfiles creating python3-foo subpackages.

Quoting the two relevant posts below. Refer to the actual threads for discussions and comments.

-------- Weitergeleitete Nachricht -------- Betreff: Re: Tumbleweed snapshot 20210115 - python can be bumpy Datum: Mon, 18 Jan 2021 13:10:21 +0100 Von: Dominique Leuenberger / DimStar An: factory@lists.opensuse.org

On Mon, 2021-01-18 at 12:00 +0000, Dominique Leuenberger wrote:

...

Packages changed:   python-rpm-macros (20200824.8fa42a7 -> 20210112.86f4d9d)

=== Details ===

==== python-rpm-macros ==== Version update (20200824.8fa42a7 -> 20210112.86f4d9d

This change has potential for quite some headaches - it was in Staging for a long time to get things sorted out 'reasonably well', BUT:

depending on your python-* modules installed, this can be a rough weekfor you.

There is a large number of packages that did not like the change (none of the ring packages, so 'most' users probably won't feel it)

If you are a python-* maintainer and see your packages newly fail, please try to help everybody to get your packages back on track. Benjamin Greiner has proven to be very helpful in those cases.

The main change is that the python-FOO spec files (when using the long established python-single-spec style, which we had already for py2/py3 in place) will produce python36-FOO and python38-FOO (the 38-FOO provides/obsoletes python3-FOO, helping for the migrationpath)

The 'not too distant'; future should see this concept further enhanced with python39 added to the mix. But that is not even staged. Let's first iron out glitches with the two python3.x variants.

Cheers, Dominique

-------- Weitergeleitete Nachricht -------- Betreff: Python 3 parallel install (Re: Tumbleweed - Review of the week 2020/52) Datum: Sat, 26 Dec 2020 16:01:42 +0100 Von: Ben Greiner An: factory@lists.opensuse.org, python@lists.opensuse.org, packaging@lists.opensuse.org

Hello,

my apologies in advance if this mail reaches you up to three times, but in my opinion the topic is relevant and important to reach people subscribed to all three mailing lists.

Am 25.12.20 um 18:34 schrieb Dominique Leuenberger / DimStar an factory@lists.opensuse.org:

...

* Multiple python 3 versions parallel installable. Adding to python 3.8, version 3.6 will be reintroduced. Python modules will be built for both versions.

This line sounds rather innocent, but it has severe implications:

Every package python-foo, which uses the so called singlespec macro %python_subpackages, will also try to build a python36-foo package. The whole build process will fail if a step in that particular flavor fails or if building for more than one flavor will create conflicts. We took care [1] of all the packages in Ring0 and Ring1, which popped up as problematic in the staging project. But there are many more packages, which will see the change the first time, when the staging project will be accepted into Factory. You can refer to the documented changes in [1] for examples how to fix a package. There are also some updates to the wiki [2] and the documentation of python-rpm-macros [3].

In particular, look out for:

- Packages already skipping Python 2 will start to produce more than one package. Avoid duplicate files by using update-alternatives (there are macros for it in python-rpm-macros), or put common files into unflavored subpackages.

- If you provide or require python3-foo, it will only do that for the primary python interpreter. Replace `BuildRequires python3-foo` by `BuildRequires %{python_module foo}` and let the %python_subpackages macro do the work for all Tags and macros where it can replace the unflavored variants e.g.:

  * `Requires: python-bar` instead of python3-bar.   * `%python_sitelib` instead of `%python3_sitelib` in `%files`

- Some packages need extra packages backporting stuff to Python 3.6, e.g. importlib-metadata or dataclasses. See black as an example how to deal with this [4]

- If upstream does not support python 3.6 anymore (Numpy already deprecates to support it in new releases, according to NEP 29 [5]) you can use `%define skip_python36 1`. All depending packages need to do the same. Alternatively a branched package can provide an older version for this flavor, e.g. python-ipython715 has been created to provide the last version which support Python 3.6.

- Python "apps" not following the flavored python-foo naming scheme, will only collect files for one (hopefully the primary python3 providing) flavor during the packaging phase. Remove %python_modules, %python_build, %python_install, %python_expand and the sort, as it unnecessarily pulls in packages for all python flavors and tries to build and install into multiple sitelib/sitearch directories. Replace by calling python3 directly or use the equivalent %python3_* macros.

- Some non-singlespec packages only create python3-foo. They will either need an update to include python36-foo, python38-foo (and python39-foo in the near future), or all depending packages must only build for the primary python3, too. `%define pythons python3` or skip all non-primary interpreters.

- The previous item is also true for many packages, which have a python bindings subpackage but are not Python only. We introduced %python_subpackage_only so that these packages now can take advantage of the singlespec macros as well. The tracker comment on GitHub [6] has links to a few examples how to use it.

- %ifpython3 and %python3_only are evil. They have been deprecated for some months already. Essentially, they fail to recognize the new flavors python36 and python38 which replace python3. OTOH, older distributions will continue to use the python3 flavor. We have introduced a new %python_provides macro, but did not modify %ifpython3 or %python3_only to incorporate this, because it is not automatically clear whether the conditioned code block shall apply to all flavors of Python3 packages or only to the primary interpreter. Replace by something like

  * `%if "%{python_flavor}" == "python3" || "%{?python_provides}" == "python3"` for sections only provided by the primary flavor.

  * `%if 0%{python_version_nodots} > 34` or `%if "%{python_flavor}" != "python2"` for section applicable to all Python 3 flavors.

Cheers and happy coding,

Ben

[1] https://github.com/openSUSE/python-rpm-macros/issues/66

[2] https://en.opensuse.org/openSUSE:Packaging_Python

[3] https://github.com/openSUSE/python-rpm-macros/blob/master/README.md

[4] https://build.opensuse.org/request/show/853412

[5] https://numpy.org/neps/nep-0029-deprecation_policy.html

[6] https://github.com/openSUSE/python-rpm-macros/issues/66#issuecomment-7155383...

Hi Axel, Am 19.01.21 um 22:33 schrieb Axel Braun:

Hello Ben, What happens if one builds only python3 and the interpreter changes from 3.8 to 3.9. The stuff installed under ..python38/site-packages should then not be accessible anymore? Schöne Grüße Axel

If I understand you correctly, you have the following situation for pkgA: - You either:   * explicitly `%define pythons python3`, or   * don't use %python_subpackages, %python_expand, unflavored      %python_build, %python_install, %pytest, %python_sitelib in %files,      and so on. If any, you literally specify (Build)Requires: python3-pkgB. - If any, you use %python3_xxxx macros. - You either produce a binary package python3-pkgA or have an app named   pkgA without the python prefix. By python3, you always refer to the primary interpreter. At the time the /usr/bin/python3 starts to point to /usr/bin/python3.9 (note the dot in between), all singlespec enabled packages python-pkgB will move the `Provides: python3-pkgB=%{version}-%{release}` and matching`Obsoletes:` from the python38-pkgB package to python39-pkgB. So for example at the time, when pkgA-1.0-1 was built, it built against python3-pkgB-0.9-1 provided by python38-pkgB-0.9-1. The change of the primary provider will trigger a rebuild for pkgA and it will now build against python3-pkgB-0.9-2 provided by python39-pkgB-0.9-2. At the very least, python-pkgB is python-base. So then pkgA moves from /usr/lib(64)/python3.8/site-packages/ to python3.9/site-packages. Cheers, Ben