On 28.2.2017 12:31, Thomas Bechtold wrote:
Hi,
On Fri, 2017-02-17 at 18:31 +0100, jan matejek wrote:
7. If you are using update-alternatives, remove them. Instead mark the executable as %python3_only: %python3_only %{_bindir}/yourbinary In most cases, we only need one version of the executable. If the purpose of the tool is, e.g., reading EXIF metadata, we don't care if python 2 or 3 reads them. (And the library files are still installed for both.)
Why? What if I only want the py2 version (including only the py2 dependencies)? Having the "binary" only shipped in the py3 package means that I need all python3 packages installed.
Why would you want "only the py2 version?" if it's a tool for which python is an implementation detail, you *should not care* which version of python it is using. The point of this is gradually moving towards python3-as-default. This should mean that after enough packages are converted, the typical installation will only have a Python 3 stack, not a Python 2 one. In the meantime, you will need both, which is impractical, but it seems better than doing a big switch-flip and mass-changing every "python-*" to "python3-*". Also IIRC this (having both stacks) is already the case because of some stacks (KDE, also GNOME i think?) moving to python 3. OTOH, If it actually matters which python version you're using, then of course you keep both and optionally provide update-alternatives. That's what the addendum to this point says.
Best
Tom