[Python-Dev] PEP 594: Removing dead batteries from the standard library

Neil Schemenauer nas-python at arctrix.com
Tue May 21 15:59:48 EDT 2019

On 2019-05-21, Terry Reedy wrote:
> The problem with this argument, taken by itself, it that it would argue for
> adding to the stdlib 100s or 1000s of modules or packages that would be
> useful to many more people than the modules proposed to be dropped.

I don't think it does.  We are not talking about 100s or 1000s of
modules.  We are talking about modules which have been in Python's
stdlib for years or decades.  If I have a script that uses one of
these modules and it gets removed, my script breaks.

Installing it from PyPI is not really a great solution.  We are
going to be breaking working scripts just like if we add new
language keywords, etc.  I think we need to be extremely careful
with trying to maintain backwards compatibility, at least as far as
we reasonably can.

The problem I have with this PEP is that I think it both too
aggressive and too conservative at the same time.  For almost all
modules on the list, I'm sure there will be many people who are
harmed by its removal.  OTOH, having to maintain all of the modules
in the stdlib is a heavy burden.  Also, new users can be lured into
using a module that is not really the best solution anymore.

Here is an alternative, straw man, proposal.  Split the CPython repo
into two parts:

    - core Python: minimal possible stdlib
    - everything else

When Python is released, provide installers for a Python that only
includes the "core" part and a second installer that includes
everything else.  I realize this is more work for the release team.
Hopefully with some scripting, it will not be too labour intensive.

The core Python installer should become the recommended installer.
People who need backwards compability with older versions of Python
can download the big installer package.

To help the people who need 100s or 1000s of extra PyPI packages, we
could develop a tool that creates a "sumo" Python installer,
grabbing packages from PyPI and building a installer package.  To
install that package, you would not need network access.  That
doesn't need to happen right away.  Also, maybe other Python
distributions can fill that need if core Python devs don't want to
build it.



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