[Python-ideas] PEP: Distributing a Subset of the Standard Library

[Tomas Orsava]

On 11/28/2016 03:32 PM, Paul Moore wrote:
> On 28 November 2016 at 13:28, Tomas Orsava <torsava at redhat.com> wrote:
>> The ``.missing.py`` extension will be added to the end of the list, and
>> configured to be handled by ``SourceFileLoader``.  Thus, if a module is not
>> found in its proper location, the ``XYZ.missing.py`` file is found and
>> executed, and further locations are not searched.
> Am I right to think that if a user had a file tkinter.missing.py in
> the current directory, then they'd get that in preference to the
> stdlib tkinter? Obviously this is no different from having a
> tkinter.py file in that directory, so it's not like this is a major
> problem, but it might be worth pointing out this minor
> incompatibility.

Correct, both tkinter.py and tkinter.missing.py in the current directory 
will take precedence. I will note this in the backwards compatibility 
section.

> Also, and possibly more of an issue, use of the ".missing.py" file
> will mean that a user can't provide their own implementation of the
> module later on sys.path. I don'rt know if this is a significant issue
> on Unix platforms. On Windows, there is a 3rd party implementation of
> the curses module which (as I understand it) can be user installed. If
> Python included a curses.missing.py, that would no longer work.
>
> Certainly these are only minor points, but worth considering.

I believe I may have found the Windows curses implementation, it's 
called PDCurses [0], and this website [1] appears to be distributing it 
under the name `curses`.

Could some Windows user please check if compiling Python with the 
current reference implementation [2] of this PEP indeed generates a 
`curses.missing.py` file among the stdlib files? If so, we might 
consider skipping the generation of the .missing.py file for the curses 
module on Windows.

[0] http://pdcurses.sourceforge.net/
[1] http://www.lfd.uci.edu/~gohlke/pythonlibs/#curses
[2] https://www.python.org/dev/peps/pep-0534/#reference-implementation


Thank you for the feedback!