[Distutils] Deprecating little used file types/extensions on PyPI?

[Donald Stufft]

> On Aug 19, 2016, at 2:53 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> 
> Unilaterally turning the feature off would be extraordinarily hostile
> to current users - grace periods and sunset clauses are standard
> features of change management processes for a reason, even when they
> come at the cost of additional implementation complexity.


This wouldn’t be a new way of handling this, when we implemented PEP 470
new projects immediately got set to the “only files on PyPI mode” and had
no ability to change to a different mode (no reason to present an option
that was going away). Emails were sent to maintains on all projects that
had an existing external link and told that in X months all their external
links would be removed (which was implemented just as switching them to the
“only files on PyPI mode”.

Therefore, given what’s been discussed thus far, my proposal would be:

Add a hidden flag, “legacy file support” on a per project basis. All new projects
have this flag switched off, any existing project that has not ever uploaded a
file that would use this flag has it switched off, everyone else has it switched
on. Emails get sent out to maintainers of projects where it is still switched on
and they’re told “In 3 months you’ll no longer be able to upload legacy file types,
but all existing files uploaded will continue to exist”. 

Files that would fall under legacy file type:

* All types except sdist, bdist_wheel, and bdist_egg [1].
* All sdist extensions besides .tar.gz.


That prevents new (and existing) projects from getting to a point where they
depend on something that is going away when they previously didn’t and gives
existing projects a chance to update their automation and what not to handle
this scenario.


[1] We can tackle egg at a later point, when setuptools either has support for Wheels
    or is less needed.

—
Donald Stufft