On Sun, Nov 17, 2019 at 9:17 PM Kaleb Keithley <kkeithle@xxxxxxxxxx> wrote: > > On Sun, Nov 17, 2019 at 8:09 PM Brad Hubbard <bhubbard@xxxxxxxxxx> wrote: >> >> On Wed, Apr 18, 2018 at 6:27 AM Nathan Cutler <ncutler@xxxxxxx> wrote: >> > > That would be at odds to what Nathan is suggesting though, which is a >> > > hard change to Python 3. >> >> > >> > Hm, not sure what hard/soft means in this context. For any given script, >> > either it runs with Python 3, or it doesn't. And this is determined by >> > the shebang. (Unless the shebang is omitted, of course.) > > > Apologies if this has already been mentioned, but FYI, Fedora (and RHEL and CentOS by extension) do not allow ambiguous python shebangs – they _require_ explicit versioned shebangs. > > I presume that is what is meant by a hard change to Python3. > > things like: > #!/usr/bin/env python > #!/usr/bin/python > are not permitted. > > (Also not #!/usr/bin/env $anything) > > Shebangs – if there is one – in .py files must be either > #!/usr/bin/python3 > or > #!/usr/bin/python2 > > AFAIK Fedora is enforcing it, kinda. Package builds in fedora run rpmlint which checks for these kinds of things, although I'm not sure this is a test yet or if there is a test that it scores high enough to fail a build. (Ditto for package builds in the OpenSUSE OBS, i.e. they also run rpmlint, although I haven't noticed python shebang tests there either.) > I can speak somewhat authoritatively on the Fedora situation, as I've helped with implementing it. In Fedora 31, we have transitioned all "unversioned" binaries from the Python stack from Python 2 to Python 3. All "unversioned" package names have also transitioned. See https://fedoraproject.org/wiki/Changes/Python_means_Python3 In Fedora 32, the aim is to retire nearly all of the Python 2 stack. The interpreter will remain and small selection of module packages will exist too (probably in the order of dozens). See https://fedoraproject.org/wiki/Changes/RetirePython2 We have enforced packages to pick either Python 2 or Python 3 for shebangs since Fedora 30 through a build-root policy script: https://fedoraproject.org/wiki/Changes/Make_ambiguous_python_shebangs_error Somewhat relatedly, we automatically generate Python distribution dependencies by default since Fedora 30: https://fedoraproject.org/wiki/Changes/EnablingPythonGeneratorsByDefault Also related, this generator can be manually activated for EL7 and EL8 by adding the following to the top of a spec: # Enable Python dependency generation %{?python_enable_dependency_generator} You can see an example of that here: https://src.fedoraproject.org/rpms/python-hvac/blob/51406e2c7383bf15303ecf5cfa2eba3bf5116dbd/f/python-hvac.spec openSUSE is orders of magnitude behind Fedora on this. All packages are still being built dual-stack, and the preference has not been switched from Python 2 to Python 3. There is no dependency generator for Python module dependencies, so getting a clear picture of the dependency web is much more complex. My understanding is that openSUSE will break the world on this only after Python 2 is retired from Factory in January 2020. It's going to be hard and painful, and it's because openSUSE is taking a *really* slow path to get there. -- 真実はいつも一つ！/ Always, there's only one truth! _______________________________________________ Dev mailing list -- dev@xxxxxxx To unsubscribe send an email to dev-leave@xxxxxxx
