Bug#839224: python-systemd: "undefined symbol" error on armhf

[Zbigniew Jędrzejewski-Szmek]

On Fri, Sep 30, 2016 at 02:24:57PM +0200, Michael Biebl wrote:
> Am 30.09.2016 um 12:39 schrieb Patrick Scharrenberg:
> > Package: python-systemd
> > Version: 232-1~bpo8+1
> > Severity: normal
> > 
> > Dear Maintainer,
> > 
> > when trying to import JournalHandler on arm architecture I get the following error:
> > 
> >   root at raspbian:~# python -c "from systemd.journal import JournalHandler"
> >   Traceback (most recent call last):
> >     File "<string>", line 1, in <module>
> >     File "/usr/lib/python2.7/dist-packages/systemd/journal.py", line 34, in <module>
> >       from ._reader import (_Reader, NOP, APPEND, INVALIDATE,
> >   ImportError: /usr/lib/python2.7/dist-packages/systemd/_reader.arm-linux-gnueabihf.so: undefined symbol: sd_journal_open_files_fd
> 
> ...
> 
> > Versions of packages python-systemd depends on:
> > ii  libc6        2.19-18+deb8u6
> > ii  libsystemd0  215-17+deb8u5
> 
> 
> 
> I guess we should bump the Build-Depends on libsystemd-dev to (>= 230)
> to ensure we build against a version with the new API. The version in
> stable was built against v215. Maybe we should build it against the bpo
> version.
> 
> I wonder if building against older versions, like v215, is supposed to
> work. Zbigniew?

There's is configuration code (based on libsystemd version as reported by
pkg-config), which decides which function calls can be used. It's most
likely that the libsystemd headers on the system on which compilation was
done were newer than the library on the target system. Other possibility
is that the configuration code is wrong. In the second case, there would
be warnings emitted during build that the function is not declared. It
would be interesting to see the logs.

Zbyszek