[Python-Dev] PEP 399: Pure Python/C Accelerator Module Compatibiilty Requirements

[R. David Murray]

On Tue, 19 Apr 2011 07:06:09 +0200, Stefan Behnel <stefan_ml at behnel.de> wrote:
> That's what makes the PEP feel so unfair to CPython developers, because 
> they are the ones who carry most of the burden of maintaining the stdlib in 
> the first place, and who will most likely continue to carry it, because 
> other implementations will continue to be occupied with their own core 
> development for another while or two. It is nice to read that other 
> implementations are contributing back patches that simplify their own reuse 
> of the stdlib code. However, that does not yet make them equal contributors 
> to the development and the maintenance of the stdlib, and is of very little 
> worth to the CPython project. It often even runs counter to the interest of 
> CPython itself.

So, the PEP makes the burden worse in that it requires that someone who
works on a module with a C accelerator must make sure that any existing
Python version and the C version stay in sync, and that *anyone* who wants
to introduce a new module into the stdlib must make sure it has a Python
version if that is practical.  IMO both of these are policies that make
sense for CPython even aside from the existence of other implementations:
Python is easier to read and understand, so where practical we should
provide a Python version of any module in the stdlib, for the benefit
of CPython users.

It doesn't sound like a great burden to me, but I'm not really qualified
to judge, since I don't generally work on C code.

Also, could you expand on "It often even runs counter to the interest of
CPython itself"?  I'm not seeing that, unless you are talking about
the parameter-binding micro-optimization, which I think we discourage
these days anyway.

> I think this social problem of the PEP can only be solved if the CPython 
> project stops doing the major share of the stdlib maintenance, thus freeing 
> its own developer capacities to focus on CPython related improvements and 
> optimisations, just like the other implementations currently do. I'm not 
> sure we want that at this point.

Personally, I consider myself an stdlib maintainer:  I only occasionally
dabble in C code when fixing bugs that annoy me for some reason.
I suppose that's why I'm one of the people backing this PEP.  I think
there are other CPython developers who might say the same thing.

--
R. David Murray           http://www.bitdance.com