[Bug 1862537] Re: No /usr/bin/python or `python` package is provided on focal

[Kai Kasurinen]

*** This bug is a duplicate of bug 1869447 ***
    https://bugs.launchpad.net/bugs/1869447

https://wiki.ubuntu.com/FocalFossa/ReleaseNotes#Python3_by_default

** Bug watch added: Debian Bug tracker #901512
   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=901512

** Also affects: python3-defaults (Debian) via
   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=901512
   Importance: Unknown
       Status: Unknown

** Changed in: python-defaults (Ubuntu)
       Status: Confirmed => Invalid

** Changed in: python-defaults (Ubuntu)
       Status: Invalid => Opinion

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to python-defaults in Ubuntu.
https://bugs.launchpad.net/bugs/1862537

Title:
  No /usr/bin/python or `python` package is provided on focal

Status in python-defaults package in Ubuntu:
  Opinion
Status in python3-defaults package in Debian:
  Unknown

Bug description:
  After upgrading to focal, there is no `/usr/bin/python` executable and
  no `python` package that can installed.

  As are result:
  - 3rd party packages that require a `python` package fail to install or are removed during upgrade or `apt --fix-broken install`
  - software installed using `pip install --user` does not function after an upgrade to focal

  The python runtime packages (`python2.7-minimal` and
  `python3.7-minimal`) should provider a `/usr/bin/python` alternative
  using the standard `update-alternatives` mechanisms, similar to how
  other compilers and interpreters, such as gcc, php or java are doing
  it.

  Workarounds:

  1. Create a dummy package to provide the `python` requirement so that
  3rd party packages will not be deemed broken and removed (for example,
  slack-desktop), by running

  equivs-build <(echo "Section: misc
  Priority: optional
  Standards-Version: 3.9.2

  Package: python-dummy
  Version: 1.0
  Provides: python
  Architecture: all
  Description: Transitional package to provide the `python` requirement for 3rd party packages
  ") && sudo dpkg -i python-dummy_1.0_all.deb

  2. Create a update-alternative configuration for /usr/bin/python that
  can be configured by the local admin to use python2 or python3, but
  defaults to python3, by running:

  update-alternatives --install /usr/bin/python python /usr/bin/python2.7 2070 \
              --slave /usr/share/man/man1/python.1.gz python.1.gz /usr/share/man/man1/python3.8.1.gz
  update-alternatives --install /usr/bin/python python /usr/bin/python3.7 3070 \
              --slave /usr/share/man/man1/python.1.gz python.1.gz /usr/share/man/man1/python3.7.1.gz
  update-alternatives --install /usr/bin/python python /usr/bin/python3.8 3080 \
              --slave /usr/share/man/man1/python.1.gz python.1.gz /usr/share/man/man1/python3.8.1.gz

  (this assumes both python2.7, python3.7 and python3.8 - which was the
  setup on my system after upgrading from eoan to focal)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/python-defaults/+bug/1862537/+subscriptions