[Python-Dev] PEP 3149 thoughts

[David Cournapeau]

On Mon, Sep 6, 2010 at 3:16 AM, Georg Brandl <g.brandl at gmx.net> wrote:
> Am 05.09.2010 19:22, schrieb "Martin v. Löwis":
>> I know the PEP is accepted, but I would still like to see some
>> changes/clarifications.
>>
>> 1. What is the effect of this PEP on Windows? Is this a Linux-only
>>    feature? If not, who is going to provide the changes for Windows?
>>    (More specifically: if this is indeed meant for Windows, and
>>    if no Windows implementation arrives before 3.2b1, I'd ask that
>>    the changes be rolled back, and integration is deferred until there
>>    is Windows support)
>
> I don't think Windows support is planned or necessary; after all, isn't the
> default installation mode on Windows to install every Python version into
> its own root direction (C:\PythonXY)?
>
>> 2. Why does the PEP recommend installing stuff into /usr/share/pyshared?
>>    According to the Linux FHS, /usr/share is for Architecture-
>>    independent data, see
>>
>> http://www.pathname.com/fhs/pub/fhs-2.3.html#USRSHAREARCHITECTUREINDEPENDENTDATA
>>    In particular, it's objective is that you can NFS-share it across,
>>    say, both SPARC Linux and x86 Linux. I believe the PEP would break
>>    this, as SPARC and x86 executables would override each other.
>
> Indeed.  I think this is probably just an oversight and should be corrected
> in the PEP.  However, it's the distributions' call anyway.

Reading the related paragraph in the PEP, it seems to me that the use
of package as in "these distributions install third party (i.e.
non-standard library) packages ..." is too vague. On Ubuntu at least,
the package content is spread out over different paths, and only
*some* files of the package are put into ...pyshared (namely, the ones
that can indeed be shared across different versions, that is onlythe
.py files in general, with the .so and the .pyc in /usr/lib/...). I
guess this is obvious for Barry and other people accustomed with
packaging on debian-like systems, but not so much for others.

Maybe the PEP would benefit from a stronger example (for example how
is a simple package with a C extension actually installed on the
system), but OTOH, this keeps changing between debian/ubuntu versions,
so a complete example may be more confusing.

cheers,

David