[Python-Dev] versioned .so files for Python 3.2

[Barry Warsaw]

On Jul 16, 2010, at 12:16 AM, Amaury Forgeot d'Arc wrote:

>2010/7/15 Barry Warsaw <barry at python.org>:
>> The first draft of PEP 3149 is ready for review.
>
>I like it!

Cool!

>I think it could mention the case where packages are not installed
>in the canonical directory, but placed elsewhere along the PYTHONPATH.
>This is how I deploy applications, for example, and the differences
>between python versions makes this a pain.

Because of the way the results of ./configure are embodied in the Makefile's
$SO variable, and that variable is used unconditionally from sysconfig (and
thus distutils), once you've configured --with-so-abi-tag, that tag will be
used globally everywhere.

I've added a note about this.

>The specific case of Windows should be mentioned: each foo.pyd
>contains the name of the python library (Python27.dll) it has been
>linked with; It must be rebuilt for a major version change.
>IMO the Windows installers provided by python.org should be built with
>a tag that contains this major number.

The current version of the PEP and my implementation do not change the Windows
builds at all.  I don't feel qualified to integrate the ideas expressed in PEP
3149 for Windows builds, but I would be happy to accept patches to either the
PEP or implementation to export the same tagging feature for Windows.

>> Thus for example, an initial implementation of PEP 384, compiled with
>> `--with-so-abi-tag=cpython-xy` would search for the following file
>> names when extension module `foo` is imported (in this order)::
>>
>>    foo.abi3.so
>>    foo.cpython-xy.so
>>    foo.so
>
>Is this the correct order? IMO the so-abi-tag is more precise and the
>two first items should be swapped.

Good point, fixed.

>PyPy would also benefit from this patch: it can now use extension
>modules, but the ABI is slightly different.  By default, PyPy would
>load only modules containing the ABI tag, and refuse foo.so which is
>incompatible for sure. But the installations could still be shared
>between Python implementations.

Interesting.  I've added a note about this to the PEP.

Thanks for the feedback.
-Barry

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