Re: The python command in Debian
On 9/17/20 3:04 PM, Nicolas Dandrimont wrote:
> Hi Matthias, others,
>
> On Thu, Jul 9, 2020, at 15:26, Matthias Klose wrote:
>> As written in [1], bullseye will not see unversioned python packages and the
>> unversioned python command being built from the python-defaults package.
>>
>> It seems to be a little bit more controversial what should happen to the python
>> command in the long term. Some people argue that python should never point to
>> python3, because it's incompatible, however Debian will have difficulties to
>> explain that decision to users who start with Python3 and are not aware of the 2
>> to 3 transition. So yes, in the long term, Debian should have a python command
>> again.
>>
>> One solution could be not to ship the python command in bullseye, forcing users
>> to adjust their local installations. This has the advantage that the error of
>> an unknown interpreter should be pretty clear. But leaves users without a
>> python command for the next two years until bullseye+1.
>>
>> Describing here a solution which is implemented for Ubuntu focal (20.04 LTS). A
>> new source package what-is-python (-perl-dont-hurt-me) ships binary packages
>> python-is-python2, python-dev-is-python2, python-is-python3 and
>> python-dev-is-python3. The python-is-python2 package provides the python
>> package, such that packages that still depend on python are not removed on a
>> distro upgrade. On new installs, python-is-python3 is not installed by default,
>> but the user gets a hint from command-not-found to install the package if he
>> tries to run python. Package dependencies on the new four binary packages have
>> to be disallowed in the Python policy. Note that such a package including the
>> Provides should only be uploaded once all dependencies on the unversioned python
>> packages are gone.
>
> So I see that the removal of `/usr/bin/python`-shipped-by-python-defaults has happened as planned. Thanks!
>
> I've just got a friend ask me about what to do to get /usr/bin/python to point at python3; Do you have any plan of uploading what-is-python for use in bullseye, at least without the python-is-python2 Provides for python as a first step (to keep the current "breakage")?
>
> In any case I think the python packaging policy at https://www.debian.org/doc/packaging-manuals/python-policy/ch-python.html should get an update to match the current status quo related to /usr/bin/python; My friend looked at it and were confused not to find a /usr/bin/python anymore.
the what-is-python package is now in NEW. Yes, the policy needs an update.
I'll put that on my TODO list. If there is too much disagreement about the
python-is-python3 package, then I plan to run it via the CTTE, and ask for an
advice how to move on.
Matthias
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