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.) > > I was very surprised to find out that, in SLES and openSUSE, the symlink > /usr/bin/python -> /usr/bin/python2 will not be changed even when the > migration of the underlying distro to Python 3 is complete. > > But then my colleagues explained why that is, and I "saw the light". > Since every single script in the distro has to be audited for Python 3 > compatibility, anyway, it makes sense to have the shebang be an explicit > declaration of said compatibility. > > By retaining the symlink at it is, all scripts start out the migration > process with an explicit declaration that they are compatible with > Python 2. Compatibility with Python 3 is signalled not by saying "it's > OK with Python 3, we tried it". It's signalled by changing the shebang. > > And this isn't unique to SUSE. Fedora is treating the shebang in the > same way, apparently. [2] Seems that if you only have python3 installed in Fedora31 this is *not* the case. # python --version Python 3.7.5 # /usr/bin/python --version Python 3.7.5 # ls -l /usr/bin/python lrwxrwxrwx. 1 root root 9 Nov 18 00:57 /usr/bin/python -> ./python3 See https://lists.fedoraproject.org/archives/list/devel-announce@xxxxxxxxxxxxxxxxxxxxxxx/thread/NFMFRKHLPUEDXSADCNXJ2N5YHK2JG3PB/ and https://fedoraproject.org/wiki/Changes/RetirePython2#The_python27_package "there is no /usr/bin/python" So the two distros are quite divergent in their approach apparently? > > It may be true that a given script is fine with Python 3, but as long as > the shebang says "python" (i.e. python2), there's no way to really find > out, is there? (Barring things like Josh's suggestion of changing the > shebang on the fly via a teuthology task/workunit, which is fine if we > decide we need a transition period, which it looks like we will.) > > Nathan > > [1] > https://github.com/kubernetes-incubator/external-storage/blob/master/ceph/cephfs/cephfs_provisioner/cephfs_provisioner.py#L27 > [2] > https://fedoraproject.org/wiki/FinalizingFedoraSwitchtoPython3#.2Fusr.2Fbin.2Fpython > _______________________________________________ > Sepia mailing list > Sepia@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/sepia-ceph.com -- Cheers, Brad _______________________________________________ Dev mailing list -- dev@xxxxxxx To unsubscribe send an email to dev-leave@xxxxxxx
