Re: public extension linked with libpython* vs. -Wl,-no-undefined
Understood, thanks!
I'll just ignore the warnings of the type
```
dpkg-shlibdeps: warning:
debian/python-pytrilinos/usr/lib/python2.7/dist-packages/PyTrilinos/NOX/_Abstract.so
contains an unresolvable reference to symbol PyString_FromFormat: it's
probably a plugin.
```
then.
Cheers,
Nico
On Mon, Mar 17, 2014 at 6:28 PM, Jakub Wilk <jwilk@debian.org> wrote:
> * Nico Schlömer <nico.schloemer@gmail.com>, 2014-03-17, 15:49:
>
>> I'm building a package with Python support and would like to reduce the
>> number of warnings that dh_python2 gives me.
>>
>> One of them is
>>
>> public extension linked with libpython2.7
>>
>> for a number of libraries. It is true that libpython2.7 is linked into
>> them,
>>
>> $ readelf -d /path/to/_ML.so
>> [...]
>> 0x0000000000000001 (NEEDED) Shared library:
>> [libpython2.7.so.1.0]
>> [...]
>>
>> but when I don't, builds with "-Wl,-no-undefined" will fail.
>>
>> What is the reason for discouraging explicit links with libpython*?
>
>
> The fundamental reason is that, except in unusual circumstances, this
> library won't be used. Python Policy §2.1 reads: "some distributions link
> extensions to libpython, but this is not the case in Debian as symbols might
> as well be resolved by '/usr/bin/python<X>.<Y>' which is not linked to
> libpython."
>
> In the past there used to be also a strong practical reason against linking
> to libpython: every ELF dependency on libpython2.X was translated by
> dpkg-shlibdeps to package dependency on python2.X, which typically meant
> that your package ended up depending on multiple different Python versions.
> But theses days there's only one supported Python (2.X) version, so this is
> not such a big deal.
>
> BTW, there's a greater chance to meet a Python expert on debian-python@ than
> here. :-P
>
> --
> Jakub Wilk
>
>
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